ANIMA WG                                                     M. Pritikin
Internet-Draft                                                     Cisco
Intended status: Standards Track                           M. Richardson
Expires: January 22, February 13, 2020                                     Sandelman
                                                               T. Eckert
                                                           Futurewei USA
                                                            M. Behringer

                                                               K. Watsen
                                                         Watsen Networks
                                                           July 21,
                                                         August 12, 2019

        Bootstrapping Remote Secure Key Infrastructures (BRSKI)
               draft-ietf-anima-bootstrapping-keyinfra-24
               draft-ietf-anima-bootstrapping-keyinfra-25

Abstract

   This document specifies automated bootstrapping of an Autonomic
   Control Plane.  To do this a remote secure key infrastructure Remote Secure Key Infrastructure (BRSKI)
   is created using manufacturer installed X.509 certificates, in
   combination with a manufacturer's authorizing service, both online
   and offline.  Bootstrapping a new device can occur using a routable
   address and a cloud service, or using only link-local connectivity,
   or on limited/disconnected networks.  Support for lower security
   models, including devices with minimal identity, is described for
   legacy reasons but not encouraged.  Bootstrapping to is complete when
   the cryptographic identity of the new key infrastructure is
   successfully deployed to the device but the device.  The established secure
   connection can be used to deploy a locally issued certificate to the
   device as well.

Status of This Memo

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   This Internet-Draft will expire on January 22, February 13, 2020.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4   5
     1.1.  Prior Bootstrapping Approaches  . . . . . . . . . . . . .   6
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   7
     1.3.  Scope of solution . . . . . . . . . . . . . . . . . . . .  10
       1.3.1.  Support environment . . . . . . . . . . . . . . . . .  10
       1.3.2.  Constrained environments  . . . . . . . . . . . . . .  10  11
       1.3.3.  Network Access Controls . . . . . . . . . . . . . . .  11
       1.3.4.  Bootstrapping is not Booting  . . . . . . . . . . . .  11  12
     1.4.  Leveraging the new key infrastructure / next steps  . . .  11  12
     1.5.  Requirements for Autonomic Network Infrastructure (ANI)
           devices . . . . . . . . . . . . . . . . . . . . . . . . .  12
   2.  Architectural Overview  . . . . . . . . . . . . . . . . . . .  12  13
     2.1.  Behavior of a Pledge  . . . . . . . . . . . . . . . . . .  14  15
     2.2.  Secure Imprinting using Vouchers  . . . . . . . . . . . .  15  16
     2.3.  Initial Device Identifier . . . . . . . . . . . . . . . .  16  17
       2.3.1.  Identification of the Pledge  . . . . . . . . . . . .  16  17
       2.3.2.  MASA URI extension  . . . . . . . . . . . . . . . . .  17  18
     2.4.  Protocol Flow . . . . . . . . . . . . . . . . . . . . . .  19  20
     2.5.  Architectural Components  . . . . . . . . . . . . . . . .  21  23
       2.5.1.  Pledge  . . . . . . . . . . . . . . . . . . . . . . .  21  23
       2.5.2.  Join Proxy  . . . . . . . . . . . . . . . . . . . . .  21  23
       2.5.3.  Domain Registrar  . . . . . . . . . . . . . . . . . .  21  23
       2.5.4.  Manufacturer Service  . . . . . . . . . . . . . . . .  21  23
       2.5.5.  Public Key Infrastructure (PKI) . . . . . . . . . . .  21  23
     2.6.  Certificate Time Validation . . . . . . . . . . . . . . .  22  24
       2.6.1.  Lack of realtime clock  . . . . . . . . . . . . . . .  22  24
       2.6.2.  Infinite Lifetime of IDevID . . . . . . . . . . . . .  22  24
     2.7.  Cloud Registrar . . . . . . . . . . . . . . . . . . . . .  22  24
     2.8.  Determining the MASA to contact . . . . . . . . . . . . .  23  25
   3.  Voucher-Request artifact  . . . . . . . . . . . . . . . . . .  23  26
     3.1.  Nonceless Voucher Requests  . . . . . . . . . . . . . . .  24  26
     3.2.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .  24  26
     3.3.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  25  27
     3.4.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  26  28
   4.  Proxying details (Pledge - Proxy -
       Registrar)  . . . . . . . .  29 . . . . . . . . . . . . . . . . .  32
     4.1.  Pledge discovery of Proxy . . . . . . . . . . . . . . . .  30  33
       4.1.1.  Proxy GRASP announcements . . . . . . . . . . . . . .  32  34
     4.2.  CoAP connection to Registrar  . . . . . . . . . . . . . .  33  35
     4.3.  Proxy discovery and communication of Registrar  . . . . .  33  36
   5.  Protocol Details (Pledge - Registrar - MASA)  . . . . . . . .  34  37
     5.1.  BRSKI-EST TLS establishment details . . . . . . . . . . .  36  39
     5.2.  Pledge Requests Voucher from the Registrar  . . . . . . .  37  40
     5.3.  Registrar Authorization of
           Pledge  . . . . . . . . . . . . . . . . . . . . . . . . .  38  41
     5.4.  BRSKI-MASA TLS establishment details  . . . . . . . . . .  38  42
       5.4.1.  MASA authentication of
               customer Registrar  . . . . . . . . . . . . . . . . .  42
     5.5.  Registrar Requests Voucher from MASA  . . . . . . . . . .  39  43
       5.5.1.  MASA renewal of expired vouchers  . . . . . . . . . .  41  45
       5.5.2.  MASA verification of voucher-request signature
               consistency . . . . . . . . . . . . . . . . . . . . .  41  45
       5.5.3.  MASA authentication of registrar (certificate)  . . .  41  45
       5.5.4.  MASA revocation checking of registrar (certificate) .  42  45
       5.5.5.  MASA verification of pledge prior-signed-voucher-
               request . . . . . . . . . . . . . . . . . . . . . . .  42  46
       5.5.6.  MASA pinning of registrar . . . . . . . . . . . . . .  42  46
       5.5.7.  MASA nonce handling . . . . . . . . . . . . . . . . .  42  46
     5.6.  MASA and Registrar Voucher Response . . . . . . . . . . .  43  46
       5.6.1.  Pledge voucher verification . . . . . . . . . . . . .  45  49
       5.6.2.  Pledge authentication of provisional TLS connection .  46  50
     5.7.  Pledge BRSKI Status Telemetry . . . . . . . . . . . . . .  47  51
     5.8.  Registrar audit log request . . . . . . . . . . . . . . .  48  52
       5.8.1.  MASA audit log response . . . . . . . . . . . . . . .  49  53
       5.8.2.  Registrar audit log verification  . . . . . . . . . .  50  54
     5.9.  EST Integration for PKI bootstrapping . . . . . . . . . .  51  56
       5.9.1.  EST Distribution of CA Certificates . . . . . . . . .  52  56
       5.9.2.  EST CSR Attributes  . . . . . . . . . . . . . . . . .  52  56
       5.9.3.  EST Client Certificate Request  . . . . . . . . . . .  53  57
       5.9.4.  Enrollment Status Telemetry . . . . . . . . . . . . .  53  57
       5.9.5.  Multiple certificates . . . . . . . . . . . . . . . .  54  58
       5.9.6.  EST over CoAP . . . . . . . . . . . . . . . . . . . .  54  59
   6.  Clarification of transfer-encoding  . . . . . . . . . . . . .  55  59
   7.  Reduced security operational modes  . . . . . . . . . . . . .  55  59
     7.1.  Trust Model . . . . . . . . . . . . . . . . . . . . . . .  55  59
     7.2.  Pledge security reductions  . . . . . . . . . . . . . . .  56  60
     7.3.  Registrar security reductions . . . . . . . . . . . . . .  57  61
     7.4.  MASA security reductions  . . . . . . . . . . . . . . . .  58  62
       7.4.1.  Issuing Nonceless vouchers  . . . . . . . . . . . . .  62
       7.4.2.  Trusting Owners on First Use  . . . . . . . . . . . .  63
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  59  63
     8.1.  The IETF XML Registry . . . . . . . . . . . . . . . . . .  64
     8.2.  Well-known EST registration . . . . . . . . . . . . . . .  59
     8.2.  64
     8.3.  PKIX Registry . . . . . . . . . . . . . . . . . . . . . .  59
     8.3.  64
     8.4.  Pledge BRSKI Status Telemetry . . . . . . . . . . . . . .  59
     8.4.  64
     8.5.  DNS Service Names . . . . . . . . . . . . . . . . . . . .  59
     8.5.  65
     8.6.  MUD File Extension for the MASA . . . . . . . . . . . . .  60  65
   9.  Applicability to the Autonomic
       Control Plane . . . . . . . . . . . . . . . . . . . . . . . .  60  65
   10. Privacy Considerations  . . . . . . . . . . . . . . . . . . .  61  66
     10.1.  MASA audit log . . . . . . . . . . . . . . . . . . . . .  61  66
     10.2.  What BRSKI-MASA reveals to the manufacturer  . . . . . .  62  67
     10.3.  Manufacturers and Used or Stolen Equipment . . . . . . .  63  69
     10.4.  Manufacturers and Grey market equipment  . . . . . . . .  64  70
     10.5.  Some mitigations for meddling by manufacturers . . . . .  65  70
   11. Security Considerations . . . . . . . . . . . . . . . . . . .  66  71
     11.1.  DoS  Denial of Service (DoS) against MASA . . . . . . . . . . . . . . . . . . . .  67  72
     11.2.  Freshness in Voucher-Requests  . . . . . . . . . . . . .  68  73
     11.3.  Trusting manufacturers . . . . . . . . . . . . . . . . .  69  74
     11.4.  Manufacturer Maintenance of trust anchors  . . . . . . .  70  75
       11.4.1.  Compromise of Manufacturer IDevID signing keys . . .  77
       11.4.2.  Compromise of MASA signing keys  . . . . . . . . . .  77
       11.4.3.  Compromise of MASA web service . . . . . . . . . . .  79
   12. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  71  80
   13. References  . . . . . . . . . . . . . . . . . . . . . . . . .  71  80
     13.1.  Normative References . . . . . . . . . . . . . . . . . .  72  80
     13.2.  Informative References . . . . . . . . . . . . . . . . .  74  83
   Appendix A.  IPv4 and non-ANI operations  . . . . . . . . . . . .  77  86
     A.1.  IPv4 Link Local addresses . . . . . . . . . . . . . . . .  78  87
     A.2.  Use of DHCPv4 . . . . . . . . . . . . . . . . . . . . . .  78  87
   Appendix B.  mDNS / DNSSD proxy discovery options . . . . . . . .  78  87
   Appendix C.  MUD Extension  . . . . . . . . . . . . . . . . . . .  79  88
   Appendix D.  Example Vouchers . . . . . . . . . . . . . . . . . .  81  90
     D.1.  Keys involved . . . . . . . . . . . . . . . . . . . . . .  81  90
       D.1.1.  MASA key pair for voucher signatures  . . . . . . . .  81  90
       D.1.2.  Manufacturer key pair for IDevID signatures . . . . .  81  90
       D.1.3.  Registrar key pair  . . . . . . . . . . . . . . . . .  82  91
       D.1.4.  Pledge key pair . . . . . . . . . . . . . . . . . . .  84  93
     D.2.  Example process . . . . . . . . . . . . . . . . . . . . .  85  94
       D.2.1.  Pledge to Registrar . . . . . . . . . . . . . . . . .  86  95
       D.2.2.  Registrar to MASA . . . . . . . . . . . . . . . . . .  89  98
       D.2.3.  MASA to Registrar . . . . . . . . . . . . . . . . . .  94 103
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  98 107

1.  Introduction

   BRSKI provides a solution for secure zero-touch (automated) bootstrap
   of new (unconfigured) devices that are called pledges in this
   document.

   This document primarily provides for the needs of the ISP and
   Enterprise focused ANIMA Autonomic Control Plane (ACP)
   [I-D.ietf-anima-autonomic-control-plane].  This bootstrap process
   satisfies the [RFC7575] section 3.3 of making all operations secure
   by default.  Other users of the BRSKI protocol will need to provide
   separate applicability statements that include privacy and security
   considerations appropriate to that deployment.  Section 9 explains
   the details applicability for this the ACP usage.

   This document describes how pledges discover (or are discovered by)
   an element of the network domain to which the pledge belongs to that
   will perform the bootstrap.  This element (device) is called the
   registrar.  Before any other operation, pledge and registrar need to
   establish mutual trust:

   1.  Registrar authenticating the pledge: "Who is this device?  What
       is its identity?"

   2.  Registrar authorizing the pledge: "Is it mine?  Do I want it?
       What are the chances it has been compromised?"

   3.  Pledge authenticating the registrar: "What is this registrar's
       identity?"

   4.  Pledge authorizing the registrar: "Should I join it?" this network?"

   This document details protocols and messages to answer the above
   questions.  It uses a TLS connection and an PKIX PKIX-shaped (X.509v3)
   certificate (an IEEE 802.1AR [IDevID] LDevID) IDevID) of the pledge to answer
   points 1 and 2.  It uses a new artifact called a "voucher" that the
   registrar receives from a "Manufacturer Authorized Signing Authority"
   (MASA) and passes to the pledge to answer points 3 and 4.

   A proxy provides very limited connectivity between the pledge and the
   registrar.

   The syntactic details of vouchers are described in detail in
   [RFC8366].  This document details automated protocol mechanisms to
   obtain vouchers, including the definition of a 'voucher-request'
   message that is a minor extension to the voucher format (see
   Section 3) defined by [RFC8366].

   BRSKI results in the pledge storing an X.509 root certificate
   sufficient for verifying the registrar identity.  In the process a
   TLS connection is established that can be directly used for
   Enrollment over Secure Transport (EST).  In effect BRSKI provides an
   automated mechanism for the "Bootstrap Distribution of CA
   Certificates" described in [RFC7030] Section 4.1.1 wherein the pledge
   "MUST [...] engage a human user to authorize the CA certificate using
   out-of-band" information".  With BRSKI the pledge now can automate
   this process using the voucher.  Integration with a complete EST
   enrollment is optional but trivial.

   BRSKI is agile enough to support bootstrapping alternative key
   infrastructures, such as a symmetric key solutions, but no such
   system is described in this document.

1.1.  Prior Bootstrapping Approaches

   To literally "pull yourself up by the bootstraps" is an impossible
   action.  Similarly the secure establishment of a key infrastructure
   without external help is also an impossibility.  Today it is commonly
   accepted that the initial connections between nodes are insecure,
   until key distribution is complete, or that domain-specific keying
   material (often pre-shared keys, including mechanisms like SIM cards)
   is pre-provisioned on each new device in a costly and non-scalable
   manner.  Existing automated mechanisms are known as non-secured
   'Trust on First Use' (TOFU) [RFC7435], 'resurrecting duckling'
   [Stajano99theresurrecting] or 'pre-staging'.

   Another prior approach has been to try and minimize user actions
   during bootstrapping, but not eliminate all user-actions.  The
   original EST protocol [RFC7030] does reduce user actions during
   bootstrap but does not provide solutions for how the following
   protocol steps can be made autonomic (not involving user actions):

   o  using the Implicit Trust Anchor [RFC7030] database to authenticate
      an owner specific service (not an autonomic solution because the
      URL must be securely distributed),

   o  engaging a human user to authorize the CA certificate using out-
      of-band data (not an autonomic solution because the human user is
      involved),

   o  using a configured Explicit TA database (not an autonomic solution
      because the distribution of an explicit TA database is not
      autonomic),

   o  and using a Certificate-Less TLS mutual authentication method (not
      an autonomic solution because the distribution of symmetric key
      material is not autonomic).

   These "touch" methods do not meet the requirements for zero-touch.

   There are "call home" technologies where the pledge first establishes
   a connection to a well known manufacturer service using a common
   client-server authentication model.  After mutual authentication,
   appropriate credentials to authenticate the target domain are
   transferred to the pledge.  This creates several problems and
   limitations:

   o  the pledge requires realtime connectivity to the manufacturer
      service,

   o  the domain identity is exposed to the manufacturer service (this
      is a privacy concern),

   o  the manufacturer is responsible for making the authorization
      decisions (this is a liability concern),

   BRSKI addresses these issues by defining extensions to the EST
   protocol for the automated distribution of vouchers.

1.2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   The following terms are defined for clarity:

   domainID:  The domain IDentity is the 160-bit SHA-1 a unique hash of based upon a
      Registrar's certificate.  If the BIT
      STRING of certificate includes the subjectPublicKey of
      SubjectKeyIdentifier (Section 4.2.1.2 [RFC5280]), then it is to be
      used as the pinned-domain-cert leaf,
      i.e. domainID.  If not, then the Registrars' certificate.  This 160-bit SHA-1 hash as
      described in that section is consistent with to be used.  This value needs to be
      calculated by both MASA (to populate the
      subject key identifier (Section 4.2.1.2 [RFC5280]). audit log), and by the
      Registrar (to recognize itself).

   drop-ship:  The physical distribution of equipment containing the
      "factory default" configuration to a final destination.  In zero-
      touch scenarios there is no staging or pre-configuration during
      drop-ship.

   imprint:  The process where a device obtains the cryptographic key
      material to identify and trust future interactions with a network.
      This term is taken from Konrad Lorenz's work in biology with new
      ducklings: during a critical period, the duckling would assume
      that anything that looks like a mother duck is in fact their
      mother.  An equivalent for a device is to obtain the fingerprint
      of the network's root certification authority certificate.  A
      device that imprints on an attacker suffers a similar fate to a
      duckling that imprints on a hungry wolf.  Securely imprinting is a
      primary focus of this document [imprinting].  The analogy to
      Lorenz's work was first noted in [Stajano99theresurrecting].

   enrollment:  The process where a device presents key material to a
      network and acquires a network specific network-specific identity.  For example
      when a certificate signing request is presented to a certification
      authority and a certificate is obtained in response.

   Pledge:  The prospective device, which has an identity installed at
      the factory.

   Voucher:  A signed artifact from the MASA that indicates to a pledge
      the cryptographic identity of the registrar it should trust.
      There are different types of vouchers depending on how that trust
      is asserted.  Multiple voucher types are defined in [RFC8366]

   Domain:  The set of entities that share a common local trust anchor.
      This includes the proxy, registrar, Domain Certificate Authority,
      Management components and any existing entity that is already a
      member of the domain.

   Domain CA:  The domain Certification Authority (CA) provides
      certification functionalities to the domain.  At a minimum it
      provides certification functionalities to a registrar and manages
      the private key that defines the domain.  Optionally, it certifies
      all elements.

   Join Registrar (and Coordinator):  A representative of the domain
      that is configured, perhaps autonomically, to decide whether a new
      device is allowed to join the domain.  The administrator of the
      domain interfaces with a "join registrar (and coordinator)" to
      control this process.  Typically a join registrar is "inside" its
      domain.  For simplicity this document often refers to this as just
      "registrar".  Within [I-D.ietf-anima-reference-model] this is
      referred to as the "join registrar autonomic service agent".
      Other communities use the abbreviation "JRC".

   (Public) Key Infrastructure:  The collection of systems and processes
      that sustain the activities of a public key system.  The registrar
      acts as an [RFC5280] and [RFC5272] (see section 7) "Registration
      Authority".

   Join Proxy:  A domain entity that helps the pledge join the domain.
      A join proxy facilitates communication for devices that find
      themselves in an environment where they are not provided
      connectivity until after they are validated as members of the
      domain.  For simplicity this document sometimes uses the term of
      'proxy' to indicate the join proxy.  The pledge is unaware that
      they are communicating with a proxy rather than directly with a
      registrar.

   Circuit Proxy:  A stateful implementation of the join proxy.  This is
      the assumed type of proxy.

   IPIP Proxy:  A stateless proxy alternative.

   MASA Service:  A third-party Manufacturer Authorized Signing
      Authority (MASA) service on the global Internet.  The MASA signs
      vouchers.  It also provides a repository for audit log information
      of privacy protected bootstrapping events.  It does not track
      ownership.

   MASA Audit Log:  A list of previous owners maintained by the MASA on
      a per device (per pledge) basis.  Described in Section 5.8.1.

   Ownership Tracker:  An Ownership Tracker service on the global
      Internet.  The Ownership Tracker uses business processes to
      accurately track ownership of all devices shipped against domains
      that have purchased them.  Although optional, this component
      allows vendors to provide additional value in cases where their
      sales and distribution channels allow for accurately tracking of
      such ownership.  Ownership tracking information is indicated in
      vouchers as described in [RFC8366]

   IDevID:  An Initial Device Identity X.509 certificate installed by
      the vendor on new equipment.

   TOFU:  Trust on First Use. Used similarly to [RFC7435].  This is
      where a pledge device makes no security decisions but rather
      simply trusts the first registrar it is contacted by.  This is
      also known as the "resurrecting duckling" model.

   nonced:  a voucher (or request) that contains a nonce (the normal
      case).

   nonceless:  a voucher (or request) that does not contain a nonce,
      relying upon accurate clocks for expiration, or which does not
      expire.

   manufacturer:  the term manufacturer is used throughout this document
      to be the entity that created the device.  This is typically the
      "original equipment manufacturer" or OEM, but in more complex
      situations it could be a "value added retailer" (VAR), or possibly
      even a systems integrator.  In general, it a goal of BRSKI to
      eliminate small distinctions between different sales channels.
      The reason for this is that it permits a single device, with a
      uniform firmware load, to be shipped directly to all customers.
      This eliminates costs for the manufacturer.  This also reduces the
      number of products supported in the field increasing the chance
      that firmware will be more up to date.

   ANI:  The Autonomic Network Infrastructure as defined by
      [I-D.ietf-anima-reference-model].  This document details specific
      requirements for pledges, proxies and registrars when they are
      part of an ANI.

   offline:  When an architectural component cannot perform realtime
      communications with a peer, either due to network connectivity or
      because the peer is turned off, the operation is said to be
      occurring offline.

1.3.  Scope of solution

1.3.1.  Support environment

   This solution (BRSKI) can support large router platforms with multi-
   gigabit inter-connections, mounted in controlled access data centers.
   But this solution is not exclusive to large equipment: it is intended
   to scale to thousands of devices located in hostile environments,
   such as ISP provided CPE devices which are drop-shipped to the end
   user.  The situation where an order is fulfilled from distributed
   warehouse from a common stock and shipped directly to the target
   location at the request of a domain owner is explicitly supported.
   That stock ("SKU") could be provided to a number of potential domain
   owners, and the eventual domain owner will not know a-priori which
   device will go to which location.

   The bootstrapping process can take minutes to complete depending on
   the network infrastructure and device processing speed.  The network
   communication itself is not optimized for speed; for privacy reasons,
   the discovery process allows for the pledge to avoid announcing its
   presence through broadcasting.

   Nomadic or mobile devices often need to acquire credentials to access
   the network at the new location.  An example of this is mobile phone
   roaming among network operators, or even between cell towers.  This
   is usually called handoff.  BRSKI does not provide a low-latency
   handoff which is usually a requirement in such situations.  For these
   solutions BRSKI can be used to create a relationship (an LDevID) with
   the "home" domain owner.  The resulting credentials are then used to
   provide credentials more appropriate for a low-latency handoff.

1.3.2.  Constrained environments

   Questions have been posed as to whether this solution is suitable in
   general for Internet of Things (IoT) networks.  This depends on the
   capabilities of the devices in question.  The terminology of
   [RFC7228] is best used to describe the boundaries.

   The solution described in this document is aimed in general at non-
   constrained (i.e., class 2+ [RFC7228]) devices operating on a non-
   Challenged network.  The entire solution as described here is not
   intended to be useable as-is by constrained devices operating on
   challenged networks (such as 802.15.4 LLNs).

   Specifically, there are protocol aspects described here that might
   result in congestion collapse or energy-exhaustion of intermediate
   battery powered routers in an LLN.  Those types of networks SHOULD
   NOT use this solution.  These limitations are predominately related
   to the large credential and key sizes required for device
   authentication.  Defining symmetric key techniques that meet the
   operational requirements is out-of-scope but the underlying protocol
   operations (TLS handshake and signing structures) have sufficient
   algorithm agility to support such techniques when defined.

   The imprint protocol described here could, however, be used by non-
   energy constrained devices joining a non-constrained network (for
   instance, smart light bulbs are usually mains powered, and speak
   802.11).  It could also be used by non-constrained devices across a
   non-energy constrained, but challenged network (such as 802.15.4).
   The certificate contents, and the process by which the four questions
   above are resolved do apply to constrained devices.  It is simply the
   actual on-the-wire imprint protocol that could be inappropriate.

1.3.3.  Network Access Controls

   This document presumes that network access control has either already
   occurred, is not required, or is integrated by the proxy and
   registrar in such a way that the device itself does not need to be
   aware of the details.  Although the use of an X.509 Initial Device
   Identity is consistent with IEEE 802.1AR [IDevID], and allows for
   alignment with 802.1X network access control methods, its use here is
   for pledge authentication rather than network access control.
   Integrating this protocol with network access control, perhaps as an
   Extensible Authentication Protocol (EAP) method (see [RFC3748]), is
   out-of-scope.

1.3.4.  Bootstrapping is not Booting

   This document describes "bootstrapping" as the protocol used to
   obtain a local trust anchor.  It is expected that this trust anchor,
   along with any additional configuration information subsequently
   installed, is persisted on the device across system restarts
   ("booting").  Bootstrapping occurs only infrequently such as when a
   device is transferred to a new owner or has been reset to factory
   default settings.

1.4.  Leveraging the new key infrastructure / next steps

   As a result of the protocol described herein, the bootstrapped
   devices have the Domain CA trust anchor in common.  An end entity
   certificate has optionally been issued from the Domain CA.  This
   makes it possible to securely deploy functionalities across the
   domain, e.g:

   o  Device management.

   o  Routing authentication.

   o  Service discovery.

   The major intended beneficiary is that it possible to use the
   credentials deployed by this protocol to secure the Autonomic Control
   Plane (ACP) ([I-D.ietf-anima-autonomic-control-plane]).

1.5.  Requirements for Autonomic Network Infrastructure (ANI) devices

   The BRSKI protocol can be used in a number of environments.  Some of
   the options in this document are the result of requirements that are
   out of the ANI scope.  This section defines the base requirements for
   ANI devices.

   For devices that intend to become part of an Autonomic Network
   Infrastructure (ANI) ([I-D.ietf-anima-reference-model]) that includes
   an Autonomic Control Plane
   ([I-D.ietf-anima-autonomic-control-plane]), the BRSKI protocol MUST
   be implemented.

   The pledge must perform discovery of the proxy as described in
   Section 4.1 using GRASP DULL [I-D.ietf-anima-grasp] M_FLOOD
   announcements.

   Upon successfully validating a voucher artifact, a status telemetry
   MUST be returned.  See Section 5.7.

   An ANIMA ANI pledge MUST implement the EST automation extensions
   described in Section 5.9.  They supplement the [RFC7030] EST to
   better support automated devices that do not have an end user.

   The ANI Join Registrar ASA Autonomic Service Agent (ASA) MUST support all
   the BRSKI and above listed EST operations.

   All ANI devices SHOULD support the BRSKI proxy function, using
   circuit proxies over the ACP.  (See Section 4.3)

2.  Architectural Overview

   The logical elements of the bootstrapping framework are described in
   this section.  Figure 1 provides a simplified overview of the
   components.

                                              +------------------------+
      +--------------Drop Ship--------------->| Vendor Service         |
      |                                       +------------------------+
      |                                       | M anufacturer|         |
      |                                       | A uthorized  |Ownership|
      |                                       | S igning     |Tracker  |
      |                                       | A uthority   |         |
      |                                       +--------------+---------+
      |                                                      ^
      |                                                      |  BRSKI-
      V                                                      |   MASA
   +-------+     ............................................|...
   |       |     .                                           |  .
   |       |     .  +------------+       +-----------+       |  .
   |       |     .  |            |       |           |       |  .
   |Pledge |     .  |   Join     |       | Domain    <-------+  .
   |       |     .  |   Proxy    |       | Registrar |          .
   |       <-------->............<-------> (PKI RA)  |          .
   |       |        |        BRSKI-EST   |           |          .
   |       |     .  |            |       +-----+-----+          .
   |IDevID |     .  +------------+             | e.g. RFC7030   .
   |       |     .           +-----------------+----------+     .
   |       |     .           | Key Infrastructure         |     .
   |       |     .           | (e.g., PKI Certificate     |     .
   +-------+     .           |       Authority)           |     .
                 .           +----------------------------+     .
                 .                                              .
                 ................................................
                               "Domain" components

                      Figure 1 1: Architecture Overview

   We assume a multi-vendor network.  In such an environment there could
   be a Manufacturer Service for each manufacturer that supports devices
   following this document's specification, or an integrator could
   provide a generic service authorized by multiple manufacturers.  It
   is unlikely that an integrator could provide Ownership Tracking
   services for multiple manufacturers due to the required sales channel
   integrations necessary to track ownership.

   The domain is the managed network infrastructure with a Key
   Infrastructure the pledge is joining.  The domain provides initial
   device connectivity sufficient for bootstrapping through a proxy.
   The domain registrar authenticates the pledge, makes authorization
   decisions, and distributes vouchers obtained from the Manufacturer
   Service.  Optionally the registrar also acts as a PKI Registration Certification
   Authority.

2.1.  Behavior of a Pledge

   The pledge goes through a series of steps, which are outlined here at
   a high level.

                  ------------
                 /  Factory   \
                 \  default   /
                  -----+------
                       |
                +------v-------+
                | (1) Discover |
   +------------>              |
   |            +------+-------+
   |                   |
   |            +------v-------+
   |            | (2) Identity |
   ^------------+              |
   | rejected   +------+-------+
   |                   |
   |            +------v-------+
   |            | (3) Request  |
   |            |     Join     |
   |            +------+-------+
   |                   |
   |            +------v-------+
   |            | (4) Imprint  |
   ^------------+              |
   | Bad MASA   +------+-------+
   | response          |  send Voucher Status Telemetry
   |            +------v-------+
   |            | (5) Enroll   |<---+ (non-error HTTP codes  )
   ^------------+              |\___/ (e.g. 202 'Retry-After')
   | Enroll     +------+-------+
   | Failure           |
   |              -----v------
   |             /  Enrolled  \
   ^------------+             |
    Factory      \------------/
    reset

                      Figure 2: pledge state diagram Pledge State Diagram

   State descriptions for the pledge are as follows:

   1.  Discover a communication channel to a registrar.

   2.  Identify itself.  This is done by presenting an X.509 IDevID
       credential to the discovered registrar (via the proxy) in a TLS
       handshake.  (The registrar credentials are only provisionally
       accepted at this time).

   3.  Request to join the discovered registrar.  A unique nonce is
       included ensuring that any responses can be associated with this
       particular bootstrapping attempt.

   4.  Imprint on the registrar.  This requires verification of the
       manufacturer service provided voucher.  A voucher contains
       sufficient information for the pledge to complete authentication
       of a registrar.  This document details this step in depth.

   5.  Enroll.  After imprint an authenticated TLS (HTTPS) connection
       exists between pledge and registrar.  Enrollment over Secure
       Transport (EST) [RFC7030] is can then used to obtain a domain
       certificate from a registrar.

   The pledge is now a member of, and can be managed by, the domain and
   will only repeat the discovery aspects of bootstrapping if it is
   returned to factory default settings.

   This specification details integration with EST enrollment so that
   pledges can optionally obtain a locally issued certificate, although
   any REST interface could be integrated in future work.

2.2.  Secure Imprinting using Vouchers

   A voucher is a cryptographically protected artifact (a (using a digital
   signature) to the pledge device authorizing a zero-touch imprint on
   the registrar domain.

   The format and cryptographic mechanism of vouchers is described in
   detail in [RFC8366].

   Vouchers provide a flexible mechanism to secure imprinting: the
   pledge device only imprints when a voucher can be validated.  At the
   lowest security levels the MASA can indiscriminately issue vouchers
   and log claims of ownership by domains.  At the highest security
   levels issuance of vouchers can be integrated with complex sales
   channel integrations that are beyond the scope of this document.  The
   sales channel integration would verify actual (legal) ownership of
   the pledge by the domain.  This provides the flexibility for a number
   of use cases via a single common protocol mechanism on the pledge and
   registrar devices that are to be widely deployed in the field.  The
   MASA services have the flexibility to leverage either the currently
   defined claim mechanisms or to experiment with higher or lower
   security levels.

   Vouchers provide a signed but non-encrypted communication channel
   among the pledge, the MASA, and the registrar.  The registrar
   maintains control over the transport and policy decisions decisions, allowing
   the local security policy of the domain network to be enforced.

2.3.  Initial Device Identifier

   Pledge authentication and pledge voucher-request signing is via a
   PKIX
   PKIX-shaped certificate installed during the manufacturing process.
   This is the 802.1AR Initial Device Identifier (IDevID), and it
   provides a basis for authenticating the pledge during the protocol
   exchanges described here.  There is no requirement for a common root
   PKI hierarchy.  Each device manufacturer can generate its own root
   certificate.  Specifically, the IDevID enables:

   1.  Uniquely identifying the pledge by the Distinguished Name (DN)
       and subjectAltName (SAN) parameters in the IDevID.  The unique
       identification of a pledge in the voucher objects are derived
       from those parameters as described below.  Section 10.2 discussed
       privacy implications.

   2.  Provides a cryptographic authentication of the pledge to the
       Registrar (see Section 5.3).

   3.  Secure auto-discovery of the pledge's MASA by the registrar (see
       Section 2.8).

   4.  Signing of voucher-request by the pledge's IDevID (see
       Section 3).

   5.  Provides a cryptographic authentication of the pledge to the MASA
       (see Section 5.5.5).

   Section 7.2.13 of [IDevID] discusses keyUsage and extendedKeyUsage
   extensions in the IDevID certificate.  Any restrictions included
   reduce the utility of the IDevID and so this specification RECOMMENDS
   that no key usage restrictions be included.  Additionally, [RFC5280]
   section 4.2.1.3 does not require key usage restrictions for end
   entity certificates.

2.3.1.  Identification of the Pledge

   In the context of BRSKI, pledges are uniquely identified by a
   "serial-number".  This serial-number is used both in the "serial-
   number" field of voucher or voucher-requests (see Section 3) and in
   local policies on registrar or MASA (see Section 5).

   The following fields are defined in [IDevID] and [RFC5280]:

   o  The subject field's DN encoding MUST include the "serialNumber"
      attribute with the device's unique serial number.  (from [IDevID]
      section 7.2.8, and [RFC5280] section 4.1.2.4's list of standard
      attributes)

   o  The subject-alt field's encoding MAY include a non-critical
      version of the RFC4108 defined HardwareModuleName.  (from [IDevID]
      section 7.2.9) If the IDevID is stored in a Trusted Platform
      Module (TPM), then this field MAY contain the TPM identification
      rather than the device's serial number.  If both fields are
      present, then the subject field takes precedence.

   and they are used as follows by the pledge to build the "serial-
   number" that is placed in the voucher-request.  In order to build it,
   the fields need to be converted into a serial-number of "type
   string".  The following methods are used depending on the first
   available IDevID certificate field (attempted in this order):

   1.  [RFC4519] section 2.31 provides an example ("WI-3005") of the
       Distinguished Name "serialNumber" attribute.  [RFC4514] indicates
       this is a printable string so no encoding is necessary.

   2.  The HardwareModuleName hwSerialNum OCTET STRING.  This value is
       base64 encoded to convert it to a printable string format.

   The above process to locate the serial-number MUST be performed by
   the pledge when filling out the voucher-request.  Signed voucher-
   requests are always passed up to the MASA.

   As explained in Section 5.5 the Registrar MUST extract the serial-
   number again itself from the pledge's TLS certificate.  It can
   consult the serial-number in the pledge-request if there are any
   possible confusion about the source of the serial-number (hwSerialNum
   vs serialNumber).

2.3.2.  MASA URI extension

   This document defines a new PKIX non-critical certificate extension
   to carry the MASA URI.  This extension is intended to be used in the
   IDevID certificate.  The URI is represented as described in
   Section 7.4 of [RFC5280].

   Any Internationalized Resource Identifiers (IRIs) MUST be mapped to
   URIs as specified in Section 3.1 of [RFC3987] before they are placed
   in the certificate extension.

   The IRI URI provides the authority information.  The BRSKI "/.well-known"
   tree ([RFC5785]) is described in Section 5.

   As explained in [RFC5280] section 7.4, a

   A complete IRI SHOULD URI MAY be in this extension, including the scheme, iauthority, 'scheme',
   'authority', and ipath.  As a 'path', The complete URI will typically be used in
   diagnostic or experimental situations.  Typically, (and in
   consideration to constrained systems, systems), this MAY SHOULD be reduced to only
   the
   iauthority, 'authority', in which case a scheme of "https://" ([RFC7230]
   section 2.7.3) and ipath 'path' of "/.well-known/est" is to be assumed, as
   explained in Section 5.

   The registrar can assume that only the iauthority 'authority' is present in the
   extension, if there are no slash ("/") characters in the extension.

   Section 7.4 of [RFC5280] calls out various schemes that MUST be
   supported, including LDAP, HTTP and FTP.  However, the registrar MUST
   use HTTPS for the BRSKI-MASA connection.

   The new extension is identified as follows:

   <CODE BEGINS>

   MASAURLExtnModule-2016 { iso(1) identified-organization(3) dod(6)
   internet(1) security(5) mechanisms(5) pkix(7)
   id-mod(0) id-mod-MASAURLExtn2016(TBD) }

   DEFINITIONS IMPLICIT TAGS ::= BEGIN

   -- EXPORTS ALL --

   IMPORTS
   EXTENSION
   FROM PKIX-CommonTypes-2009
     { iso(1) identified-organization(3) dod(6) internet(1)
       security(5) mechanisms(5) pkix(7) id-mod(0)
       id-mod-pkixCommon-02(57) }

   id-pe FROM PKIX1Explicit-2009
     { iso(1) identified-organization(3) dod(6) internet(1)
        security(5) mechanisms(5) pkix(7) id-mod(0)
        id-mod-pkix1-explicit-02(51) } ;

   MASACertExtensions EXTENSION ::= { ext-MASAURL, ... }
   ext-MASAURL EXTENSION ::= { SYNTAX MASAURLSyntax
   IDENTIFIED BY id-pe-masa-url }

   id-pe-masa-url OBJECT IDENTIFIER ::= { id-pe TBD }

   MASAURLSyntax ::= IA5String

   END

   <CODE ENDS>

                      Figure 3: MASAURL ASN.1 Module

   The choice of id-pe is based on guidance found in Section 4.2.2 of
   [RFC5280], "These extensions may be used to direct applications to
   on-line information about the issuer or the subject".  The MASA URL
   is precisely that: online information about the particular subject.

2.4.  Protocol Flow

   A representative flow is shown in Figure 3: 4
   +--------+         +---------+    +------------+     +------------+
   | Pledge |         | Circuit |    | Domain     |     | Vendor     |
   |        |         | Join    |    | Registrar  |     | Service    |
   |        |         | Proxy   |    |  (JRC)     |     | (MASA)     |
   +--------+         +---------+    +------------+     +------------+
     |                     |                   |           Internet |
   [discover]              |                   |                    |
     |<-RFC4862 IPv6 addr  |                   |                    |
     |<-RFC3927 IPv4 addr  | Appendix A        |  Legend            |
     |-------------------->|                   |  C - circuit       |
     | optional: mDNS query| Appendix B        |      join proxy    |
     | RFC6763/RFC6762     |                   |  P - provisional   |
     |<--------------------|                   |    TLS connection  |
     | GRASP M_FLOOD       |                   |                    |
     |   periodic broadcast|                   |                    |
   [identity]              |                   |                    |
     |<------------------->C<----------------->|                    |
     |         TLS via the Join Proxy          |                    |
     |<--Registrar TLS server authentication---|                    |
   [PROVISIONAL accept of server cert]         |                    |
     P---X.509 client authentication---------->|                    |
   [request join]                              |                    |
     P---Voucher Request(w/nonce for voucher)->|                    |
     P                  /-------------------   |                    |
     P                  |                 [accept device?]          |
     P                  |                 [contact Vendor]          |
     P                  |                      |--Pledge ID-------->|
     P                  |                      |--Domain ID-------->|
     P                  |                      |--optional:nonce--->|
     P              optional:                  |     [extract DomainID]
     P        can occur in advance             |     [update audit log]
     P            if nonceleess                |                    |
     P                  |                      |<- voucher ---------|
     P                  \-------------------   | w/nonce if provided|
     P<------voucher---------------------------|                    |
   [imprint]                                   |                    |
     |-------voucher status telemetry--------->|                    |
     |                                         |<-device audit log--|
     |                             [verify audit log and voucher]   |
     |<--------------------------------------->|                    |
   [enroll]                                    |                    |
     | Continue with RFC7030 enrollment        |                    |
     | using now bidirectionally authenticated |                    |
     | TLS session.                            |                    |
   [enrolled]                                  |                    |

                 Figure 3

2.5.  Architectural Components

2.5.1.  Pledge

   The pledge is the 4: Protocol Time Sequence Diagram

   On initial bootstrap, a new device that is attempting to join.  Until the
   pledge completes the enrollment process, it has link-local network
   connectivity only (the pledge) uses a local service
   autodiscovery (GRASP or mDNS) to the locate a join proxy.

2.5.2.  Join Proxy  The join proxy provides HTTPS connectivity between
   connects the pledge and to a local registrar (the JRC).

   Having found a candidate registrar, the
   registrar.  A circuit proxy mechanism is described in Section 4.
   Additional mechanisms, fledgling pledge sends some
   information about itself to the registrar, including its serial
   number in the form of a CoAP mechanism voucher request and a stateless
   IPIP mechanism are the subject its device identity
   certificate (IDevID) as part of future work.

2.5.3.  Domain Registrar the TLS session.

   The domain's registrar operates as can determine whether it expected such a device to
   appear, and locates a MASA.  The location of the BRSKI-MASA client when
   requesting vouchers from MASA is usually
   found in an extension in the IDevID.  Having determined that the MASA (see Section 5.4).  The registrar
   operates as
   is suitable, the BRSKI-EST server when pledges entire information from the initial voucher request vouchers (see
   Section 5.1).  The registrar operates as
   (including device serial number) is transmitted over the BRSKI-EST server
   "Registration Authority" if internet in
   a TLS protected channel to the pledge requests an end entity
   certificate over manufacturer, along with information
   about the BRSKI-EST connection (see Section 5.9). registrar/owner.

   The registrar uses an Implicit Trust Anchor database for
   authenticating manufacturer can then apply policy based on the provided
   information, as well as other sources of information (such as sales
   records), to decide whether to approve the claim by the BRSKI-MASA TLS connection MASA certificate.  The registrar uses a different Implicit Trust Anchor database for
   authenticating to
   own the BRSKI-EST TLS connection pledge client
   certificate.  Configuration or distribution of these trust anchor
   databases device; if the claim is out-of-scope of this specification.

2.5.4.  Manufacturer Service accepted, a voucher is issued that
   directs the device to accept its new owner.

   The Manufacturer Service provides two logically separate functions: voucher is returned to the Manufacturer Authorized Signing Authority (MASA) described in
   Section 5.5 and Section 5.6, and registrar, but not immediately to the
   device -- the registrar has an ownership tracking/auditing
   function described in Section 5.7 and Section 5.8.

2.5.5.  Public Key Infrastructure (PKI)

   The Public Key Infrastructure (PKI) administers certificates for opportunity to examine the
   domain of concerns, providing voucher,
   the trust anchor(s) for it MASA's audit logs, and allowing
   enrollment of pledges with domain certificates.

   The voucher provides a method for the distribution other sources of a single PKI
   trust anchor (as information to determine
   whether the "pinned-domain-cert").  A distribution of device has been tampered with, and whether the
   full set bootstrap
   should be accepted.

   No filtering of current trust anchors information is possible using in the signed voucher, so
   this is a binary yes-or-no decision.  If the optional EST
   integration.

   The domain's registrar acts accepts the
   voucher as an [RFC5272] Registration Authority,
   requesting certificates a proper one for pledges from its device, the Key Infrastructure. voucher is returned to
   the pledge for imprinting.

   The expectations of voucher also includes a trust anchor that the PKI are unchanged from EST [[RFC7030]]. pledge uses as
   representing the owner.  This
   document does not place any additional architectural requirements on is used to successfully bootstrap from
   an environment where only the Public Key Infrastructure.

2.6.  Certificate Time Validation

2.6.1.  Lack of realtime clock

   Many devices when bootstrapping do not have knowledge of manufacturer has built-in trust by the current
   time.  Mechanisms such as Network Time Protocols cannot be secured
   until bootstrapping is complete.  Therefore bootstrapping is defined
   in
   device into an environment where the owner now has a method that does not require knowledge of PKI footprint on
   the current time.  A
   pledge MAY ignore all time stamps in device.

   When BRSKI is followed with EST this single footprint is further
   leveraged into the voucher full owner's PKI and in a LDevID for the
   certificate validity periods if it does not know device.
   Subsequent reporting steps provide flows of information to indicate
   success/failure of the current time. process.

2.5.  Architectural Components

2.5.1.  Pledge

   The pledge is exposed to dates in the following five places:
   registrar certificate notBefore, registrar certificate notAfter,
   voucher created-on, and voucher expires-on.  Additionally, CMS
   signatures contain a signingTime.

   If the voucher contains a nonce then device that is attempting to join.  Until the
   pledge MUST confirm completes the
   nonce matches enrollment process, it has link-local network
   connectivity only to the proxy.

2.5.2.  Join Proxy

   The join proxy provides HTTPS connectivity between the original pledge voucher-request.  This ensures and the
   voucher
   registrar.  A circuit proxy mechanism is fresh.  See described in Section 5.2.

2.6.2.  Infinite Lifetime of IDevID

   [RFC5280] explains that long lived pledge certificates "SHOULD be
   assigned 4.
   Additional mechanisms, including a CoAP mechanism and a stateless
   IPIP mechanism are the GeneralizedTime value subject of 99991231235959Z".  Registrars
   MUST support such lifetimes and SHOULD support ignoring pledge
   lifetimes if they did not follow the RFC5280 recommendations.

   For example, IDevID may have incorrect lifetime of N <= 3 years,
   rendering replacement pledges from storage useless after N years
   unless registrars support ignoring such a lifetime.

2.7.  Cloud future work.

2.5.3.  Domain Registrar

   There exist operationally open network wherein devices gain
   unauthenticated access to

   The domain's registrar operates as the Internet at large.  In these use cases BRSKI-MASA client when
   requesting vouchers from the management domain for MASA (see Section 5.4).  The registrar
   operates as the device needs to be discovered within BRSKI-EST server when pledges request vouchers (see
   Section 5.1).  The registrar operates as the larger Internet.  These are less likely within BRSKI-EST server
   "Registration Authority" if the anima scope
   but may be more important in pledge requests an end entity
   certificate over the future.

   There are additionally some greenfield situations involving BRSKI-EST connection (see Section 5.9).

   The registrar uses an
   entirely new installation where a device may have some kind of
   management uplink that it can use (such as via 3G network Implicit Trust Anchor database for
   instance).  In such a future situation, the device might use this
   management interface to learn that it should configure itself to
   become the local registrar.

   In order to support these scenarios,
   authenticating the pledge MAY contact a well
   known URI of a cloud registrar if a local BRSKI-MASA TLS connection MASA certificate.  The
   registrar cannot be
   discovered or if the pledge's target use cases do not include a local
   registrar.

   If the pledge uses a well known URI for contacting a cloud registrar
   an different Implicit Trust Anchor database (see [RFC7030]) MUST be used to
   authenticate service as described in [RFC6125].  This is consistent
   with for
   authenticating the human user configuration BRSKI-EST TLS connection pledge client
   certificate.  Configuration or distribution of an EST server URI in [RFC7030]
   which also depends on RFC6125.

2.8.  Determining the MASA to contact

   The registrar needs to be able to contact a MASA that these trust anchor
   databases is trusted by
   the pledge in order to obtain vouchers.  There are three mechanisms
   described: out-of-scope of this specification.

2.5.4.  Manufacturer Service

   The device's Initial Device Identifier (IDevID) will normally contain Manufacturer Service provides two logically separate functions:
   the MASA URL as detailed Manufacturer Authorized Signing Authority (MASA) described in
   Section 2.3.  This is 5.5 and Section 5.6, and an ownership tracking/auditing
   function described in Section 5.7 and Section 5.8.

2.5.5.  Public Key Infrastructure (PKI)

   The Public Key Infrastructure (PKI) administers certificates for the RECOMMENDED
   mechanism.

   If
   domain of concern, providing the registrar is integrated with [I-D.ietf-opsawg-mud] trust anchor(s) for it and allowing
   enrollment of pledges with domain certificates.

   The voucher provides a method for the
   pledge IDevID contains the id-pe-mud-url then distribution of a single PKI
   trust anchor (as the registrar MAY
   attempt to obtain "pinned-domain-cert").  A distribution of the MASA URL from
   full set of current trust anchors is possible using the MUD file. optional EST
   integration.

   The MUD file
   extension domain's registrar acts as an [RFC5272] Registration Authority,
   requesting certificates for pledges from the MASA URL is defined in Appendix C.

   It can be operationally difficult to ensure Key Infrastructure.

   The expectations of the necessary X.509
   extensions PKI are in unchanged from EST [[RFC7030]].  This
   document does not place any additional architectural requirements on
   the pledge's IDevID due to the difficulty Public Key Infrastructure.

2.6.  Certificate Time Validation

2.6.1.  Lack of realtime clock

   Many devices when bootstrapping do not have knowledge of
   aligning current pledge manufacturing with software releases and
   development.  As a final fallback the registrar MAY current
   time.  Mechanisms such as Network Time Protocols cannot be manually
   configured or distributed secured
   until bootstrapping is complete.  Therefore bootstrapping is defined
   with a MASA URL for each manufacturer.
   Note framework that the registrar can only select the configured MASA URL based
   on the trust anchor -- so manufacturers can only leverage this
   approach if they ensure a single MASA URL works for all pledge's
   associated with each trust anchor.

3.  Voucher-Request artifact

   Voucher-requests are how vouchers are requested.  The semantics does not require knowledge of the vouchers are described below, in the YANG model. current time.
   A pledge forms MAY ignore all time stamps in the "pledge voucher-request" voucher and submits in the
   certificate validity periods if it to does not know the
   registrar. current time.

   The registrar pledge is exposed to dates in turn forms the "registrar voucher-request", following five places:
   registrar certificate notBefore, registrar certificate notAfter,
   voucher created-on, and
   submits voucher expires-on.  Additionally, CMS
   signatures contain a signingTime.

   A pledge with a real time clock in which it to has confidence in, MUST
   check the MASA.

   The "proximity-registrar-cert" leaf is used above time fields in all certificates and signatures that
   ir processes.

   If the pledge voucher-
   requests.  This provides voucher contains a method for nonce then the pledge to assert MUST confirm the
   registrar's proximity.

   The "prior-signed-voucher-request" leaf is used in registrar voucher-
   requests.  If present, it is
   nonce matches the signed original pledge voucher-request.  This
   provides a method for the registrar to forward ensures the pledge's signed
   request to
   voucher is fresh.  See Section 5.2.

2.6.2.  Infinite Lifetime of IDevID

   [RFC5280] explains that long lived pledge certificates "SHOULD be
   assigned the MASA.  This completes transmission GeneralizedTime value of 99991231235959Z".  Registrars
   MUST support such lifetimes and SHOULD support ignoring pledge
   lifetimes if they did not follow the signed
   "proximity-registrar-cert" leaf.

   Unless otherwise signaled (outside RFC5280 recommendations.

   For example, IDevID may have incorrect lifetime of N <= 3 years,
   rendering replacement pledges from storage useless after N years
   unless registrars support ignoring such a lifetime.

2.7.  Cloud Registrar

   There exist operationally open networks wherein devices gain
   unauthenticated access to the voucher-request artifact), Internet at large.  In these use cases
   the
   signing structure is as defined management domain for vouchers, see [RFC8366].

3.1.  Nonceless Voucher Requests

   A registrar MAY also retrieve nonceless vouchers by sending nonceless
   voucher-requests to the MASA in order device needs to obtain vouchers for use when be discovered within
   the registrar does not have connectivity larger Internet.  The case where a device can boot and get access
   to larger Internet are less likely within the MASA.  No "prior-
   signed-voucher-request" leaf would ANIMA ACP scope but may
   be included.  The registrar will
   also need to know more important in the serial number of future.  In the pledge.  This document
   does not provide ANIMA ACP scope, new devices
   will be quarantined behind a mechanism Join Proxy.

   There are additionally some greenfield situations involving an
   entirely new installation where a device may have some kind of
   management uplink that it can use (such as via 3G network for
   instance).  In such a future situation, the registrar device might use this
   management interface to learn that in an
   automated fashion.  Typically this will be done via scanning of bar-
   code or QR-code on packaging, or via some sales channel integration.

3.2.  Tree Diagram

   The following tree diagram illustrates it should configure itself to
   become the local registrar.

   In order to support these scenarios, the pledge MAY contact a high-level view well
   known URI of a
   voucher-request document.  The voucher-request builds upon cloud registrar if a local registrar cannot be
   discovered or if the
   voucher artifact pledge's target use cases do not include a local
   registrar.

   If the pledge uses a well known URI for contacting a cloud registrar
   an Implicit Trust Anchor database (see [RFC7030]) MUST be used to
   authenticate that service as described in [RFC8366].  The tree diagram [RFC6125].  This is
   described in [RFC8340].  Each node
   consistent with the human user configuration of an EST server URI in
   [RFC7030] which also depends on RFC6125.

2.8.  Determining the diagram MASA to contact

   The registrar needs to be able to contact a MASA that is fully described trusted by
   the YANG module pledge in Section 3.4.  Please review the YANG module for
   a detailed description of the voucher-request format.

   module: ietf-voucher-request

     grouping voucher-request-grouping
       +-- voucher
          +-- created-on?                      yang:date-and-time
          +-- expires-on?                      yang:date-and-time
          +-- assertion?                       enumeration
          +-- serial-number                    string
          +-- idevid-issuer?                   binary
          +-- pinned-domain-cert?              binary
          +-- domain-cert-revocation-checks?   boolean
          +-- nonce?                           binary
          +-- last-renewal-date?               yang:date-and-time
          +-- prior-signed-voucher-request?    binary
          +-- proximity-registrar-cert?        binary

3.3.  Examples

   This section provides voucher-request examples for illustration
   purposes. order to obtain vouchers.  There are three mechanisms
   described:

   The contents of device's Initial Device Identifier (IDevID) will normally contain
   the certificate have been elided to save
   space.  For MASA URL as detailed examples, see Appendix D.2.  These examples
   conform to the encoding rules defined in [RFC7951].

   Example (1)  The following example illustrates a pledge voucher-
                request.  The assertion leaf Section 2.3.  This is indicated as 'proximity'
                and the registrar's TLS server certificate is included
                in RECOMMENDED
   mechanism.

   If the 'proximity-registrar-cert' leaf.  See
                Section 5.2.

   {
       "ietf-voucher-request:voucher": {
           "nonce": "62a2e7693d82fcda2624de58fb6722e5",
           "serial-number" : "JADA123456789",
           "created-on": "2017-01-01T00:00:00.000Z",
           "proximity-registrar-cert": "base64encodedvalue=="
       }
   }

   Example (2)  The following example illustrates a registrar voucher-
                request.  The 'prior-signed-voucher-request' leaf is
                populated integrated with [RFC8520] and the pledge's voucher-request (such as pledge IDevID
   contains the
                prior example).  The pledge's voucher-request is a
                binary object.  In id-pe-mud-url then the JSON encoding used here it must
                be base64 encoded.  The nonce, created-on and assertion
                is carried forward.  The serial-number is extracted from registrar MAY attempt to obtain
   the pledge's Client Certificate MASA URL from the TLS connection.
                See Section 5.5.

   {
       "ietf-voucher-request:voucher": {
           "nonce": "62a2e7693d82fcda2624de58fb6722e5",
           "created-on": "2017-01-01T00:00:02.000Z",
           "idevid-issuer": "base64encodedvalue=="
           "serial-number": "JADA123456789"
           "prior-signed-voucher-request": "base64encodedvalue=="
       }
   }

   Example (3)  The following example illustrates a registrar voucher-
                request. MUD file.  The 'prior-signed-voucher-request' leaf is not
                populated with MUD file extension for the pledge's voucher-request nor MASA
   URL is the
                nonce leaf.  This form might defined in Appendix C.

   It can be used by a registrar
                requesting a voucher when operationally difficult to ensure the necessary X.509
   extensions are in the pledge's IDevID due to the difficulty of
   aligning current pledge can not communicate manufacturing with the registrar (such as when it is powered down, or
                still in packaging), software releases and therefore could not submit
   development.  As a
                nonce.  This scenario is most useful when final fallback the registrar
                is aware that it will not MAY be able to reach the manually
   configured or distributed with a MASA
                during deployment.  See Section 5.5.

   {
       "ietf-voucher-request:voucher": {
           "created-on":    "2017-01-01T00:00:02.000Z",
           "idevid-issuer": "base64encodedvalue=="
           "serial-number": "JADA123456789"
       }
   }

3.4.  YANG Module

   Following is URL for each manufacturer.
   Note that the registrar can only select the configured MASA URL based
   on the trust anchor -- so manufacturers can only leverage this
   approach if they ensure a single MASA URL works for all pledge's
   associated with each trust anchor.

3.  Voucher-Request artifact

   Voucher-requests are how vouchers are requested.  The semantics of
   the vouchers are described below, in the YANG [RFC7950] module formally extending model.

   A pledge forms the [RFC8366]
   voucher into a voucher-request.

<CODE BEGINS> file "ietf-voucher-request@2018-02-14.yang"
module ietf-voucher-request {
  yang-version 1.1;

  namespace
    "urn:ietf:params:xml:ns:yang:ietf-voucher-request";
  prefix "vch";

  import ietf-restconf {
    prefix rc;
    description "This import statement is only present "pledge voucher-request", signs it with it's
   IDevID and submits it to access the yang-data extension defined registrar.

   The registrar in RFC 8040.";
    reference "RFC 8040: RESTCONF Protocol";
  }
  import ietf-voucher {
    prefix v;
    description "This module defines turn forms the format for a voucher,
        which is produced by a pledge's manufacturer or
        delegate (MASA) "registrar voucher-request", signs it
   with it's Registrar keypair and submits it to securely assign the MASA.

   The "proximity-registrar-cert" leaf is used in the pledge voucher-
   requests.  This provides a method for the pledge to
        an 'owner', so that assert the
   registrar's proximity.

   The "prior-signed-voucher-request" leaf is used in registrar voucher-
   requests.  If present, it is the signed pledge may establish voucher-request
   artifact.  This provides a secure
        connection method for the registrar to forward the owner's network infrastructure";

    reference "RFC 8366: Voucher Profile for Bootstrapping Protocols";
  }

  organization
   "IETF ANIMA Working Group";

  contact
   "WG Web:   <http://tools.ietf.org/wg/anima/>
    WG List:  <mailto:anima@ietf.org>
    Author:   Kent Watsen
              <mailto:kwatsen@juniper.net>
    Author:   Michael H. Behringer
              <mailto:Michael.H.Behringer@gmail.com>
    Author:   Steinthor Bjarnason
              <mailto:sbjarnason@arbor.net>
    Author:   Max Pritikin
              <mailto:pritikin@cisco.com>
    Author:   Michael Richardson
              <mailto:mcr+ietf@sandelman.ca>";

  description
   "This module defines
   pledge's signed request to the format for a voucher request.
    It is a superset MASA.  This completes transmission of
   the voucher itself.
    It provides content signed "proximity-registrar-cert" leaf.

   Unless otherwise signaled (outside the voucher-request artifact), the
   signing structure is as defined for vouchers, see [RFC8366].

3.1.  Nonceless Voucher Requests

   A registrar MAY also retrieve nonceless vouchers by sending nonceless
   voucher-requests to the MASA for consideration
    during a voucher request.

    The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
    'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
    'MAY', and 'OPTIONAL' in this document are order to be interpreted as
    described in BCP 14 RFC2119 RFC8174 when, and only when, they
    appear in all capitals, as shown here.

    Copyright (c) 2017 IETF Trust and the persons identified as
    authors of the code. All rights reserved.

    Redistribution and obtain vouchers for use in source and binary forms, with or without
    modification, is permitted pursuant to, and subject when
   the registrar does not have connectivity to the license
    terms contained in, MASA.  No "prior-
   signed-voucher-request" leaf would be included.  The registrar will
   also need to know the Simplified BSD License set forth in Section
    4.c serial number of the IETF Trust's Legal Provisions Relating to IETF Documents
    (http://trustee.ietf.org/license-info). pledge.  This version of document
   does not provide a mechanism for the registrar to learn that in an
   automated fashion.  Typically this YANG module is part will be done via scanning of RFC XXXX; see the RFC
    itself for full legal notices.";

  revision "2018-02-14" {
    description
     "Initial version";
    reference
     "RFC XXXX: Voucher Profile for Bootstrapping Protocols";
  }

  // Top-level statement
  rc:yang-data voucher-request-artifact {
    uses voucher-request-grouping;
  }

  // Grouping defined for future usage
  grouping voucher-request-grouping {
    description
      "Grouping to allow reuse/extensions in future work.";

    uses v:voucher-artifact-grouping {
      refine "voucher/created-on" {
        mandatory false;
      }

      refine "voucher/pinned-domain-cert" {
        mandatory false;
      }

      refine "voucher/domain-cert-revocation-checks" {
        description "The domain-cert-revocation-checks field
                     is not valid in a voucher request, and
                     any occurence MUST be ignored";
      }

      refine "voucher/assertion" {
        mandatory false;
        description "Any assertion included in voucher
              requests SHOULD be ignored by the MASA.";
      }

      augment "voucher"  {
        description
          "Adds leaf nodes appropriate for requesting vouchers.";

        leaf prior-signed-voucher-request {
          type binary;
          description
            "If it is necessary to change a voucher, bar-
   code or re-sign and
             forward QR-code on packaging, or via some sales channel integration.

3.2.  Tree Diagram

   The following tree diagram illustrates a voucher that was previously provided along high-level view of a
             protocol path, then
   voucher-request document.  The voucher-request builds upon the previously signed
   voucher SHOULD be
             included artifact described in this field.

             For example, a pledge might sign a voucher request
             with a proximity-registrar-cert, and the registrar
             then includes it [RFC8366].  The tree diagram is
   described in [RFC8340].  Each node in the prior-signed-voucher-request field.
             This diagram is a simple mechanism fully described
   by the YANG module in Section 3.4.  Please review the YANG module for
   a chain detailed description of trusted
             parties to change a voucher request, while
             maintaining the prior signature information.

             The Registrar and MASA MAY examine the prior signed
             voucher information for the
             purposes of policy decisions. For example this information
             could be useful to a MASA to determine that both pledge and
             registrar agree on proximity assertions. The MASA SHOULD
             remove all prior-signed-voucher-request information when
             signing a voucher-request format.

   module: ietf-voucher-request

     grouping voucher-request-grouping
       +---- voucher
          +---- created-on?                      yang:date-and-time
          +---- expires-on?                      yang:date-and-time
          +---- assertion?                       enumeration
          +---- serial-number                    string
          +---- idevid-issuer?                   binary
          +---- pinned-domain-cert?              binary
          +---- domain-cert-revocation-checks?   boolean
          +---- nonce?                           binary
          +---- last-renewal-date?               yang:date-and-time
          +---- prior-signed-voucher-request?    binary
          +---- proximity-registrar-cert?        binary

              Figure 5: YANG Tree diagram for imprinting so as to minimize Voucher-Request

3.3.  Examples

   This section provides voucher-request examples for illustration
   purposes.  The contents of the
             final voucher size.";
        }

        leaf proximity-registrar-cert {
          type binary;
          description
            "An X.509 v3 certificate structure as specified by RFC 5280,
             Section 4 encoded using have been elided to save
   space.  For detailed examples, see Appendix D.2.  These examples
   conform to the ASN.1 distinguished encoding rules (DER), as specified defined in ITU-T X.690. [RFC7951].

   Example (1)  The first certificate in following example illustrates a pledge voucher-
                request.  The assertion leaf is indicated as 'proximity'
                and the Registrar registrar's TLS server
             certificate_list sequence  (see [RFC5246]) presented by
             the Registrar to the Pledge. This MUST be populated in a
             Pledge's voucher request if a proximity assertion certificate is
             requested.";
        }
      }
    } included
                in the 'proximity-registrar-cert' leaf.  See
                Section 5.2.

   {
       "ietf-voucher-request:voucher": {
           "assertion": "proximity",
           "nonce": "62a2e7693d82fcda2624de58fb6722e5",
           "serial-number" : "JADA123456789",
           "created-on": "2017-01-01T00:00:00.000Z",
           "proximity-registrar-cert": "base64encodedvalue=="
       }
   }

<CODE ENDS>

4.  Proxying details (Pledge - Proxy - Registrar)

   The role

         Figure 6: JSON representation of the proxy is to facilitate communications. example Voucher-Request

   Example (2)  The proxy
   forwards packets between the pledge and following example illustrates a registrar that has been
   provisioned to the proxy via GRASP discovery.

   This section defines a stateful proxy mechanism which is referred to
   as a "circuit" proxy. voucher-
                request.  The proxy does not terminate the TLS handshake: it passes streams of
   bytes onward without examination.  A proxy MUST NOT assume any
   specific TLS version.

   A Registrar can directly provide the proxy announcements described
   below, in which case 'prior-signed-voucher-request' leaf is
                populated with the announced port can point directly to pledge's voucher-request (such as the
   Registrar itself.
                prior example).  The pledge's voucher-request is a
                binary CMS signed object.  In this scenario the pledge is unaware that there JSON encoding used
                here it must be base64 encoded.  The nonce, created-on
                and assertion is no proxing occurring.  This carried forward.  The serial-number is useful for Registrars servicing
   pledges on directly connected networks.

   As a result of the proxy Discovery process in Section 4.1.1,
                extracted from the port
   number exposed by pledge's Client Certificate from the proxy does
                TLS connection.  See Section 5.5.

   {
       "ietf-voucher-request:voucher": {
           "assertion" : "proximity",
           "nonce": "62a2e7693d82fcda2624de58fb6722e5",
           "created-on": "2017-01-01T00:00:02.000Z",
           "idevid-issuer": "base64encodedvalue=="
           "serial-number": "JADA123456789"
           "prior-signed-voucher-request": "base64encodedvalue=="
       }
   }

   Figure 7: JSON representation of example Prior-Signed Voucher-Request

   Example (3)  The following example illustrates a registrar voucher-
                request.  The 'prior-signed-voucher-request' leaf is not need to be well known, or
   require an IANA allocation.

   During
                populated with the discovery of pledge's voucher-request nor is the Registrar
                nonce leaf.  This form might be used by a registrar
                requesting a voucher when the Join Proxy, pledge can not communicate
                with the Join
   Proxy will also learn which kinds of proxy mechanisms are available. registrar (such as when it is powered down, or
                still in packaging), and therefore could not submit a
                nonce.  This will allow scenario is most useful when the Join Proxy registrar
                is aware that it will not be able to use reach the lowest impact mechanism
   which the Join Proxy and Registrar have in common.

   In order to permit the proxy functionality to be implemented on the
   maximum variety of devices the chosen mechanism should use the
   minimum amount MASA
                during deployment.  See Section 5.5.

   {
       "ietf-voucher-request:voucher": {
           "created-on":    "2017-01-01T00:00:02.000Z",
           "idevid-issuer": "base64encodedvalue=="
           "serial-number": "JADA123456789"
       }
   }

         Figure 8: JSON representation of state on the proxy device.  While many devices in
   the ANIMA target space will be rather large routers, Offline Voucher-Request

3.4.  YANG Module

   Following is a YANG [RFC7950] module formally extending the proxy
   function [RFC8366]
   voucher into a voucher-request.

<CODE BEGINS> file "ietf-voucher-request@2018-02-14.yang"
module ietf-voucher-request {
  yang-version 1.1;
  namespace
    "urn:ietf:params:xml:ns:yang:ietf-voucher-request";
  prefix "vch";

  import ietf-restconf {
    prefix rc;
    description "This import statement is likely only present to be implemented access
       the yang-data extension defined in RFC 8040.";
    reference "RFC 8040: RESTCONF Protocol";
  }

  import ietf-voucher {
    prefix v;
    description "This module defines the control plane CPU of such
   a device, with available capabilities format for the proxy function similar
   to many class 2 IoT devices.

   The document [I-D.richardson-anima-state-for-joinrouter] provides a
   more extensive analysis and background of the alternative proxy
   methods.

4.1.  Pledge discovery of Proxy

   The result of discovery voucher,
        which is produced by a logical communication with a registrar,
   through a proxy.  The proxy is transparent pledge's manufacturer or
        delegate (MASA) to the pledge.  The
   communication between the securely assign a pledge is over IPv6 Link-Local addresses.

   To discover the proxy to
        an 'owner', so that the pledge performs the following actions:

   1.  MUST: Obtains may establish a local address using IPv6 methods as described in
       [RFC4862] IPv6 Stateless Address AutoConfiguration.  Use of
       [RFC4941] temporary addresses is encouraged.  To limit pervasive
       monitoring ( [RFC7258]), a new temporary address MAY use a short
       lifetime (that is, set TEMP_PREFERRED_LIFETIME secure
        connection to be short).
       Pledges will generally prefer use of IPv6 Link-Local addresses,
       and discovery of proxy will be by Link-Local mechanisms.  IPv4
       methods are described in Appendix A

   2.  MUST: Listen for GRASP M_FLOOD ([I-D.ietf-anima-grasp])
       announcements of the objective: "AN_Proxy".  See section
       Section 4.1.1 owner's network infrastructure";

    reference "RFC 8366: Voucher Profile for Bootstrapping Protocols";
  }

  organization
   "IETF ANIMA Working Group";

  contact
   "WG Web:   <http://tools.ietf.org/wg/anima/>
    WG List:  <mailto:anima@ietf.org>
    Author:   Kent Watsen
              <mailto:kwatsen@juniper.net>
    Author:   Michael H. Behringer
              <mailto:Michael.H.Behringer@gmail.com>
    Author:   Toerless Eckert
              <mailto:ttef@cs.fau.de>
    Author:   Max Pritikin
              <mailto:pritikin@cisco.com>
    Author:   Michael Richardson
              <mailto:mcr+ietf@sandelman.ca>";

  description
   "This module defines the details of the objective.  The pledge MAY
       listen concurrently format for other sources of information, see
       Appendix B.

   Once a proxy voucher request.
    It is discovered the pledge communicates with a registrar
   through the proxy using superset of the bootstrapping protocol defined in
   Section 5.

   While voucher itself.
    It provides content to the GRASP M_FLOOD mechanism is passive MASA for the pledge, the
   optional other methods (mDNS, and IPv4 methods) are active. consideration
    during a voucher request.

    The
   pledge SHOULD run those methods key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
    'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
    'MAY', and 'OPTIONAL' in parallel with listening this document are to for be interpreted as
    described in BCP 14 RFC2119 RFC8174 when, and only when, they
    appear in all capitals, as shown here.

    Copyright (c) 2019 IETF Trust and the
   M_FLOOD.  The active methods SHOULD exponentially back-off to a
   maximum persons identified as
    authors of one hour to avoid overloading the network code. All rights reserved.

    Redistribution and use in source and binary forms, with discovery
   attempts.  Detection of change or without
    modification, is permitted pursuant to, and subject to the license
    terms contained in, the Simplified BSD License set forth in Section
    4.c of physical link status (Ethernet
   carrier for instance) SHOULD reset the exponential back off.

   The pledge could discover more than one proxy on a given physical
   interface.  The pledge can have a multitude IETF Trust's Legal Provisions Relating to IETF Documents
    (http://trustee.ietf.org/license-info).

    This version of physical interfaces as
   well: a layer-2/3 Ethernet switch may have hundreds this YANG module is part of physical
   ports.

   Each possible proxy offer SHOULD be attempted up to RFC XXXX; see the point where RFC
    itself for full legal notices.";

  revision "2018-02-14" {
    description
     "Initial version";
    reference
     "RFC XXXX: Voucher Profile for Bootstrapping Protocols";
  }

  // Top-level statement
  rc:yang-data voucher-request-artifact {
    uses voucher-request-grouping;
  }

  // Grouping defined for future usage
  grouping voucher-request-grouping {
    description
      "Grouping to allow reuse/extensions in future work.";

    uses v:voucher-artifact-grouping {
      refine "voucher/created-on" {
        mandatory false;
      }

      refine "voucher/pinned-domain-cert" {
        mandatory false;
      }

      refine "voucher/domain-cert-revocation-checks" {
        description "The domain-cert-revocation-checks field
                     is not valid in a voucher is received: while there are many ways request, and
                     any occurence MUST be ignored";
      }

      refine "voucher/assertion" {
        mandatory false;
        description "Any assertion included in which the attempt
   may fail, it does not succeed until the voucher has been validated.

   The connection attempts via a single proxy
              requests SHOULD exponentially back-
   off to a maximum of one hour to avoid overloading the network
   infrastructure.  The back-off timer for each MUST be independent of
   other connection attempts.

   Connection attempts SHOULD be run in parallel ignored by the MASA.";
      }

      augment "voucher"  {
        description
          "Adds leaf nodes appropriate for requesting vouchers.";

        leaf prior-signed-voucher-request {
          type binary;
          description
            "If it is necessary to avoid head of queue
   problems wherein an attacker running change a fake proxy voucher, or registrar could
   perform re-sign and
             forward a voucher that was previously provided along a
             protocol actions intentionally slowly.  Connection attempts
   to different proxies path, then the previously signed voucher SHOULD be sent with an interval of 3 to 5s.  The
             included in this field.

             For example, a pledge SHOULD continue to listen to for additional GRASP M_FLOOD
   messages during the connection attempts.

   Once might sign a connection to voucher request
             with a proximity-registrar-cert, and the registrar
             then includes it as the prior-signed-voucher-request field.
             This is established (e.g. establishment
   of a TLS session key) there are expectations simple mechanism for a chain of more timely
   responses, see Section 5.2.

   Once all discovered services are attempted (assuming that none
   succeeded) the device MUST return trusted
             parties to listening for GRASP M_FLOOD.  It
   SHOULD periodically retry change a voucher request, while
             maintaining the manufacturer specific mechanisms. prior signature information.

             The
   pledge Registrar and MASA MAY prioritize selection order as appropriate for examine the
   anticipated environment.

4.1.1.  Proxy GRASP announcements

   A proxy uses prior signed
             voucher information for the DULL GRASP M_FLOOD mechanism to announce itself.
   This announcement can
             purposes of policy decisions. For example this information
             could be within the same message as the ACP
   announcement detailed in [I-D.ietf-anima-autonomic-control-plane]. useful to a MASA to determine that both pledge and
             registrar agree on proximity assertions. The M_FLOOD is formatted MASA SHOULD
             remove all prior-signed-voucher-request information when
             signing a voucher for imprinting so as follows:

  [M_FLOOD, 12340815, h'fe800000000000000000000000000001', 180000,
              ["AN_Proxy", 4, 1, ""],
              [O_IPv6_LOCATOR,
                h'fe800000000000000000000000000001', IPPROTO_TCP, 4443]]

   Figure 6b: Proxy Discovery

   The formal CDDL [I-D.ietf-cbor-cddl] definition is:

 flood-message = [M_FLOOD, session-id, initiator, ttl,
                  +[objective, (locator-option / [])]]

 objective = ["AN_Proxy", objective-flags, loop-count,
                                        objective-value]

 ttl             = 180000     ; 180,000 ms (3 minutes)
 initiator = ACP address to contact Registrar
 objective-flags   = sync-only  ; minimize the
             final voucher size.";
        }

        leaf proximity-registrar-cert {
          type binary;
          description
            "An X.509 v3 certificate structure as in GRASP spec
 sync-only         = specified by RFC 5280,
             Section 4         ; M_FLOOD only requires synchronization
 loop-count        =  1         ; one hop only
 objective-value   =  any       ; none

 locator-option    = [ O_IPv6_LOCATOR, ipv6-address,
                     transport-proto, port-number ]
 ipv6-address      = the v6 LL of the Proxy
 $transport-proto /= IPPROTO_TCP   ; note this can be any value from encoded using the
                                  ; IANA protocol registry, ASN.1 distinguished encoding
             rules (DER), as per
                                  ; [GRASP] section 2.9.5.1, note 3.
 port-number      = selected by Proxy

   Figure 6c: AN_Proxy CDDL

   On a small network specified in ITU-T X.690.

             The first certificate in the Registrar MAY include TLS server
             certificate_list sequence  (the end-entity TLS certificate,
             see [RFC8446]) presented by the GRASP M_FLOOD
   announcements Registrar to locally connected networks.

   The $transport-proto above indicates the method that the pledge-
   proxy-registrar will use.  The TCP method described here is
   mandatory, and other proxy methods, such as CoAP methods not defined
   in this document are optional.  Other methods Pledge.
             This MUST NOT be enabled
   unless the Join Registrar ASA indicates support for them populated in it's own
   announcement.

4.2.  CoAP connection to Registrar

   The use of CoAP to connect from pledge to registrar a Pledge's voucher request when a
             proximity assertion is out of scope requested.";
        }
      }

    }
  }

}

<CODE ENDS>

                 Figure 9: YANG module for this document, and is described in future work.  See
   [I-D.ietf-anima-constrained-voucher].

4.3. Voucher-Request

4.  Proxying details (Pledge - Proxy discovery - Registrar)

   This section applies is normative for uses with an ANIMA ACP.  The
   use of GRASP mechanism part of the ACP.  Other users of BRSKI will
   need to define an equivalent proxy mechanism, and communication an equivalent
   mechanism to configure the proxy.

   The role of Registrar the proxy is to facilitate communications.  The proxy
   forwards packets between the pledge and a registrar SHOULD announce itself so that proxies can find it and
   determine what kind has been
   provisioned to the proxy via full GRASP ACP discovery.

   This section defines a stateful proxy mechanism which is referred to
   as a "circuit" proxy.  This is a form of connections can be terminated. Application Level Gateway
   ([RFC2663] section 2.9).

   The registrar announces itself using ACP instance proxy does not terminate the TLS handshake: it passes streams of GRASP using
   M_FLOOD messages.
   bytes onward without examination.  A registrar may announce proxy MUST NOT assume any convenient port
   number, including using a stock
   specific TLS version.  Please see {{RFC8446}} section 9.3 for details
   on TLS invariants.

   A Registrar can directly provide the proxy announcements described
   below, in which case the announced port 443.  ANI proxies MUST support
   GRASP discovery of registrars.

   The M_FLOOD is formatted as follows:

  [M_FLOOD, 12340815, h'fda379a6f6ee00000200000064000001', 180000,
              ["AN_join_registrar", 4, 255, "EST-TLS"],
              [O_IPv6_LOCATOR,
                h'fda379a6f6ee00000200000064000001', IPPROTO_TCP, 8443]]

   Figure 7a: can point directly to the
   Registrar Discovery

   The formal CDDL definition is:

   flood-message = [M_FLOOD, session-id, initiator, ttl,
                    +[objective, (locator-option / [])]]

   objective = ["AN_join_registrar", objective-flags, loop-count,
                                          objective-value]

   initiator = ACP address to contact Registrar
   objective-flags = sync-only  ; as in GRASP spec
   sync-only =  4               ; M_FLOOD only requires synchronization
   loop-count      = 255        ; mandatory maximum
   objective-value = text       ; name of itself.  In this scenario the (list of) of supported
                                ; protocols: "EST-TLS" pledge is unaware that there
   is no proxing occurring.  This is useful for RFC7030.

   Figure 7: AN_join_registrar CDDL
   The M_FLOOD message MUST be sent periodically.  The default SHOULD be
   60 seconds, Registrars which are
   servicing pledges on directly connected networks.

   As a result of the value SHOULD be operator configurable but SHOULD be proxy Discovery process in Section 4.1.1, the port
   number exposed by the proxy does not smaller than 60 seconds.  The frequency of sending MUST need to be such
   that well known, or
   require an IANA allocation.

   During the aggregate amount discovery of periodic M_FLOODs from all flooding
   sources cause only negligible traffic across the ACP.

   Here are some examples Registrar by the Join Proxy, the Join
   Proxy will also learn which kinds of locators for illustrative purposes.  Only proxy mechanisms are available.
   This will allow the first one ($transport-protocol = 6, TCP) is defined in this
   document and is mandatory Join Proxy to implement.

   locator1  = [O_IPv6_LOCATOR, fd45:1345::6789, 6,  443]
   locator2  = [O_IPv6_LOCATOR, fd45:1345::6789, 17, 5683]
   locator3  = [O_IPv6_LOCATOR, fe80::1234, 41, nil]

   A protocol of 6 indicates that TCP proxying on use the indicated port is
   desired.

   Registrars MUST announce lowest impact mechanism
   which the set of protocols that they support.
   They MUST support TCP traffic.

   Registrars MUST accept HTTPS/EST traffic on the TCP ports indicated.

   Registrars MUST support ANI TLS circuit proxy Join Proxy and therefore BRSKI
   across HTTPS/TLS native across the ACP. Registrar have in common.

   In order to permit the ANI, the Autonomic Control Plane (ACP) secured instance of
   GRASP ([I-D.ietf-anima-grasp]) MUST proxy functionality to be used for discovery implemented on the
   maximum variety of ANI
   registrar ACP addresses and ports by ANI proxies.  The TCP leg devices the chosen mechanism should use the
   minimum amount of state on the proxy connection between ANI proxy and ANI registrar therefore also
   runs across device.  While many devices in
   the ACP.

5.  Protocol Details (Pledge - Registrar - MASA)

   The pledge MUST initiate BRSKI after boot if it is unconfigured.  The
   pledge MUST NOT automatically initiate BRSKI if it has been
   configured or ANIMA target space will be rather large routers, the proxy
   function is likely to be implemented in the process control plane CPU of being configured.

   BRSKI is described as extensions such
   a device, with available capabilities for the proxy function similar
   to EST [RFC7030]. many class 2 IoT devices.

   The goal document [I-D.richardson-anima-state-for-joinrouter] provides a
   more extensive analysis and background of these
   extensions is to reduce the number alternative proxy
   methods.

4.1.  Pledge discovery of TLS connections and crypto
   operations required on the pledge. Proxy

   The registrar implements the
   BRSKI REST interface within the same "/.well-known" URI tree as result of discovery is a logical communication with a registrar,
   through a proxy.  The proxy is transparent to the
   existing EST URIs as described in EST [RFC7030] section 3.2.2. pledge.  The
   communication channel between the pledge and the registrar Join Proxy is
   referred to as "BRSKI-EST" (see Figure 1).

   The communication channel between over IPv6 Link-
   Local addresses.

   To discover the registrar and MASA is similarly
   described as extensions to EST within proxy the same "/.well-known" tree.

   For clarity this channel is referred to pledge performs the following actions:

   1.  MUST: Obtains a local address using IPv6 methods as "BRSKI-MASA".  (See
   Figure 1).

   MASA URI described in
       [RFC4862] IPv6 Stateless Address AutoConfiguration.  Use of
       [RFC4941] temporary addresses is "https://" iauthority "/.well-known/est".

   BRSKI uses existing CMS message formats for existing EST operations.
   BRSKI uses JSON [RFC8259] for all encouraged.  To limit pervasive
       monitoring ( [RFC7258]), a new operations defined here, and
   voucher formats.

   While EST section 3.2 does not insist upon temporary address MAY use of HTTP 1.1 persistent
   connections, ([RFC7230] section 6.3) BRSKI-EST connections SHOULD a short
       lifetime (that is, set TEMP_PREFERRED_LIFETIME to be short).
       Pledges will generally prefer use
   persistent connections.  The intention of this guidance is to ensure
   the provisional TLS state occurs only once, IPv6 Link-Local addresses,
       and that the subsequent
   resolution discovery of proxy will be by Link-Local mechanisms.  IPv4
       methods are described in Appendix A

   2.  MUST: Listen for GRASP M_FLOOD ([I-D.ietf-anima-grasp])
       announcements of the provision state is not subject to a MITM attack
   during a critical phase.

   Summarized automation extensions objective: "AN_Proxy".  See section
       Section 4.1.1 for the BRSKI-EST flow are:

   o details of the objective.  The pledge either attempts concurrent connections via each MAY
       listen concurrently for other sources of information, see
       Appendix B.

   Once a proxy is discovered proxy, or it times out quickly and tries connections in
      series, as explained at the end of Section 5.1.

   o  The pledge provisionally accepts the communicates with a registrar certificate during
   through the TLS handshake as detailed proxy using the bootstrapping protocol defined in
   Section 5.1.

   o  The pledge requests and validates a voucher using 5.

   While the new REST
      calls described below.

   o GRASP M_FLOOD mechanism is passive for the pledge, the
   optional other methods (mDNS, and IPv4 methods) are active.  The
   pledge completes authentication of the server certificate as
      detailed SHOULD run those methods in Section 5.6.1.  This moves parallel with listening to for the BRSKI-EST TLS
      connection out
   M_FLOOD.  The active methods SHOULD back-off by doubling to a maximum
   of one hour to avoid overloading the provisional state.

   o  Mandatory bootstrap steps conclude network with voucher discovery attempts.
   Detection of change of physical link status telemetry
      (see Section 5.7).

   The BRSKI-EST TLS connection can now be used (Ethernet carrier for EST enrollment.
   instance) SHOULD reset the back off timers.

   The extensions for pledge could discover more than one proxy on a registrar (equivalent to EST server) are:

   o  Client authentication is automated using Initial Device Identity
      (IDevID) as per the EST certificate based client authentication. given physical
   interface.  The subject field's DN encoding MUST include the "serialNumber"
      attribute with the device's unique serial number.

   o  This extends the informal set pledge can have a multitude of "identifer type" values defined
      in [RFC6125] to include physical interfaces as
   well: a SERIALNUM-ID category layer-2/3 Ethernet switch may have hundreds of identifier that
      can physical
   ports.

   Each possible proxy offer SHOULD be included in attempted up to the point where a certificate and therefore that can also be
      used for matching purposes.  As noted in that document this
   voucher is not
      a formal definition as the underlying types have been previously
      defined elsewhere.  The SERIALNUM-ID whitelist is collated
      according to manufacturer trust anchor since serial numbers received: while there are many ways in which the attempt
   may fail, it does not globally unique.

   o  The registrar requests and validates succeed until the voucher from the MASA.

   o has been validated.

   The registrar forwards the voucher connection attempts via a single proxy SHOULD exponentially back-
   off to a maximum of one hour to avoid overloading the pledge when requested.

   o network
   infrastructure.  The registrar performs log verifications back-off timer for each MUST be independent of
   other connection attempts.

   Connection attempts SHOULD be run in addition parallel to local
      authorization checks before accepting optional pledge device
      enrollment requests.

5.1.  BRSKI-EST TLS establishment details

   The pledge establishes the TLS connection with the registrar through
   the circuit avoid head of queue
   problems wherein an attacker running a fake proxy (see Section 4) but the TLS handshake is or registrar could
   perform protocol actions intentionally slowly.  Connection attempts
   to different proxies SHOULD be sent with the
   registrar. an interval of 3 to 5s.  The BRSKI-EST
   pledge is the TLS client and SHOULD continue to listen to for additional GRASP M_FLOOD
   messages during the BRSKI-EST connection attempts.

   Once a connection to a registrar is the TLS server.  All security associations established (e.g. establishment
   of a TLS session key) there are between expectations of more timely
   responses, see Section 5.2.

   Once all discovered services are attempted (assuming that none
   succeeded) the device MUST return to listening for GRASP M_FLOOD.  It
   SHOULD periodically retry any manufacturer-specific mechanisms.  The
   pledge and MAY prioritize selection order as appropriate for the registrar regardless of
   anticipated environment.

4.1.1.  Proxy GRASP announcements

   A proxy
   operations.

   Establishment of uses the BRSKI-EST TLS connection is as specified in EST
   [RFC7030] section 4.1.1 "Bootstrap Distribution of CA Certificates"
   [RFC7030] wherein the client is authenticated with DULL GRASP M_FLOOD mechanism to announce itself.
   This announcement can be within the IDevID
   certificate, and same message as the EST server (the registrar) is provisionally
   authenticated with an unverified server certificate. ACP
   announcement detailed in [I-D.ietf-anima-autonomic-control-plane].

   The pledge performs input validation of all data received until a
   voucher is verified formal CDDL [RFC8610] definition is:

 flood-message = [M_FLOOD, session-id, initiator, ttl,
                  +[objective, (locator-option / [])]]

 objective = ["AN_Proxy", objective-flags, loop-count,
                                        objective-value]

 ttl             = 180000     ; 180,000 ms (3 minutes)
 initiator = ACP address to contact Registrar
 objective-flags   = sync-only  ; as specified in Section 5.6.1 and the TLS
   connection leaves GRASP spec
 sync-only         =  4         ; M_FLOOD only requires synchronization
 loop-count        =  1         ; one hop only
 objective-value   =  any       ; none

 locator-option    = [ O_IPv6_LOCATOR, ipv6-address,
                     transport-proto, port-number ]
 ipv6-address      = the provisional state.  Until these operations are
   complete v6 LL of the pledge could be communicating with an attacker.

   A pledge that Proxy
 $transport-proto /= IPPROTO_TCP   ; note this can connect to multiple registries concurrently SHOULD
   do so.  Some devices may be unable to do so for lack of threading, or
   resource issues.  Concurrent connections defeat attempts any value from the
                                  ; IANA protocol registry, as per
                                  ; [GRASP] section 2.9.5.1, note 3.
 port-number      = selected by Proxy

           Figure 10: CDDL definition of Proxy Discovery message

   Here is an example M_FLOOD announcing a
   malicious proxy from causing a at fe80::1, on TCP Slowloris-like attack (see
   [slowloris]).

   A pledge that can not maintain as many connections as there are
   eligible proxies will need to rotate among the various choices,
   terminating connections that do not appear to be making progress.  If
   no connection is making progess after 5 seconds then port
   4443.

  [M_FLOOD, 12340815, h'fe800000000000000000000000000001', 180000,
              ["AN_Proxy", 4, 1, ""],
              [O_IPv6_LOCATOR,
                h'fe800000000000000000000000000001', IPPROTO_TCP, 4443]]

               Figure 11: Example of Proxy Discovery message

   On a small network the pledge
   SHOULD drop Registrar MAY include the oldest connection and go on GRASP M_FLOOD
   announcements to a different proxy: locally connected networks.

   The $transport-proto above indicates the
   proxy method that has been communicated with least recently.  If there were
   no other proxies discovered, the pledge MAY continue to wait, as long
   as it pledge-
   proxy-registrar will use.  The TCP method described here is concurrently listening for new
   mandatory, and other proxy announcements.

5.2.  Pledge Requests Voucher from methods, such as CoAP methods not defined
   in this document are optional.  Other methods MUST NOT be enabled
   unless the Join Registrar

   When the pledge bootstraps it makes a request ASA indicates support for a voucher them in it's own
   announcement.

4.2.  CoAP connection to Registrar

   The use of CoAP to connect from a
   registrar.

   This pledge to registrar is done with an HTTPS POST using the operation path value out of
   "/.well-known/est/requestvoucher".

   The pledge voucher-request Content-Type is:

   application/voucher-cms+json  The request scope
   for this document, and is a "YANG-defined JSON
      document that has been signed using a CMS structure" as described
      in Section 3 using the JSON encoding described in [RFC7951].  This
      voucher media type is defined in [RFC8366] future work.  See
   [I-D.ietf-anima-constrained-voucher].

4.3.  Proxy discovery and is also used for
      the pledge voucher-request. communication of Registrar

   The pledge registrar SHOULD sign the request announce itself so that proxies can find it and
   determine what kind of connections can be terminated.

   The registrar announces itself using ACP instance of GRASP using
   M_FLOOD messages.  A registrar may announce any convenient port
   number, including using a stock port 443.  ANI proxies MUST support
   GRASP discovery of registrars.

   The M_FLOOD is formatted as follows:

  [M_FLOOD, 12340815, h'fda379a6f6ee00000200000064000001', 180000,
              ["AN_join_registrar", 4, 255, "EST-TLS"],
              [O_IPv6_LOCATOR,
                h'fda379a6f6ee00000200000064000001', IPPROTO_TCP, 8443]]

         Figure 12: An example of a Registrar announcement message

   The formal CDDL definition is:

   flood-message = [M_FLOOD, session-id, initiator, ttl,
                    +[objective, (locator-option / [])]]

   objective = ["AN_join_registrar", objective-flags, loop-count,
                                          objective-value]

   initiator = ACP address to contact Registrar
   objective-flags = sync-only  ; as in GRASP spec
   sync-only =  4               ; M_FLOOD only requires synchronization
   loop-count      = 255        ; mandatory maximum
   objective-value = text       ; name of the Section 2.3 credential. (list of) of supported
                                ; protocols: "EST-TLS" for RFC7030.

       Figure 13: CDDL definition for Registrar implementations announcement message

   The M_FLOOD message MUST be sent periodically.  The default SHOULD anticipate future media types but of
   course will simply fail be
   60 seconds, the request if those types are value SHOULD be operator configurable but SHOULD be
   not yet known. smaller than 60 seconds.  The pledge SHOULD include an [RFC7231] section 5.3.2 "Accept" header
   field indicating frequency of sending MUST be such
   that the acceptable media type aggregate amount of periodic M_FLOODs from all flooding
   sources cause only negligible traffic across the ACP.

   Here are some examples of locators for illustrative purposes.  Only
   the voucher response.
   The "application/voucher-cms+json" media type first one ($transport-protocol = 6, TCP) is defined in [RFC8366]
   but constrained voucher formats are expected in the future.
   Registrar's this
   document and MASA's are expected is mandatory to be flexible in what they
   accept.

   The pledge populates the voucher-request fields as follows:

   created-on:  Pledges implement.

   locator1  = [O_IPv6_LOCATOR, fd45:1345::6789, 6,  443]
   locator2  = [O_IPv6_LOCATOR, fd45:1345::6789, 17, 5683]
   locator3  = [O_IPv6_LOCATOR, fe80::1234, 41, nil]

   A protocol of 6 indicates that have a realtime clock are RECOMMENDED to
      populate this field with TCP proxying on the current date and time in yang:date-
      and-time format.  This provides additional information to indicated port is
   desired.

   Registrars MUST announce the
      MASA.  Pledges set of protocols that have no real-time clocks MAY omit this field.

   nonce:  The pledge voucher-request they support.
   They MUST contain a cryptographically
      strong random or pseudo-random number nonce. (see [RFC4086]) Doing
      so ensures Section 2.6.1 functionality.  The nonce support TCP traffic.

   Registrars MUST NOT be
      reused for multiple bootstrapping attempts.  (The registrar
      voucher-request MAY omit accept HTTPS/EST traffic on the nonce as per Section 3.1)

   proximity-registrar-cert: TCP ports indicated.

   Registrars MUST support ANI TLS circuit proxy and therefore BRSKI
   across HTTPS/TLS native across the ACP.

   In a pledge voucher-request this is the
      first certificate in ANI, the TLS server 'certificate_list' sequence
      (see [RFC5246]) presented Autonomic Control Plane (ACP) secured instance of
   GRASP ([I-D.ietf-anima-grasp]) MUST be used for discovery of ANI
   registrar ACP addresses and ports by ANI proxies.  The TCP leg of the
   proxy connection between ANI proxy and ANI registrar to therefore also
   runs across the pledge.  This
      MUST be populated in a ACP.

5.  Protocol Details (Pledge - Registrar - MASA)

   The pledge voucher-request MUST initiate BRSKI after boot if the "proximity"
      assertion it is unconfigured.  The
   pledge MUST NOT automatically initiate BRSKI if it has been
   configured or is populated.

   All other fields MAY be omitted in the pledge voucher-request.

   An example JSON payload process of a pledge voucher-request being configured.

   BRSKI is in Section 3.3
   Example 1. described as extensions to EST [RFC7030].  The goal of these
   extensions is to reduce the number of TLS connections and crypto
   operations required on the pledge.  The registrar validates implements the client identity
   BRSKI REST interface within the same "/.well-known" URI tree as the
   existing EST URIs as described in EST [RFC7030] section 3.3.2. 3.2.2.  The registrar confirms that
   communication channel between the 'proximity'
   assertion pledge and associated 'proximity-registrar-cert' are correct.

5.3.  Registrar Authorization of Pledge

   In a fully automated network all devices must be securely identified the registrar is
   referred to as "BRSKI-EST" (see Figure 1).

   The communication channel between the registrar and authorized MASA is similarly
   described as extensions to join EST within the domain.

   A Registrar accepts or declines a request same "/.well-known" tree.
   For clarity this channel is referred to join as "BRSKI-MASA".  (See
   Figure 1).

   The MASA URI is "https://" authority "/.well-known/est".

   BRSKI uses existing CMS message formats for existing EST operations.
   BRSKI uses JSON [RFC8259] for all new operations defined here, and
   voucher formats.

   While EST section 3.2 does not insist upon use of HTTP 1.1 persistent
   connections, ([RFC7230] section 6.3) BRSKI-EST connections SHOULD use
   persistent connections.  The intention of this guidance is to ensure
   the domain, based
   on provisional TLS state occurs only once, and that the authenticated identity presented.  Automated acceptance
   criteria include:

   o  allow any device subsequent
   resolution of a specific type (as determined by the X.509
      IDevID),

   o  allow any device from a specific vendor (as determined by the
      X.509 IDevID),

   o  allow a specific device from a vendor (as determined by the X.509
      IDevID) against provision state is not subject to a domain white list.  (The mechanism for checking MITM attack
   during a shared white list potentially used by multiple Registrars is out
      of scope). critical phase.

   If these validations fail non-persistent connections are used, then both the pledge and the
   registrar SHOULD respond with MUST remember the HTTP
   404 error code.  If certificates seen, and also sent for the voucher-request is in an unknown format, then
   an HTTP 406 error code is more appropriate.  A situation that could
   be resolved with administrative action (such
   first connection.  They MUST check each subsequent connections for
   the same certificates, and each end MUST use the same certificates as adding a vendor to
   well.  This places a
   whitelist) MAY be responded with an 403 HTTP error code.

   If authorization is successful difficult restriction on rolling certificates on
   the registrar obtains a voucher from Registrar.

   Summarized automation extensions for the MASA service (see Section 5.5) BRSKI-EST flow are:

   o  The pledge either attempts concurrent connections via each
      discovered proxy, or it times out quickly and returns that MASA signed
   voucher to tries connections in
      series, as explained at the end of Section 5.1.

   o  The pledge provisionally accepts the registrar certificate during
      the TLS handshake as described detailed in Section 5.6.

5.4.  BRSKI-MASA TLS establishment details 5.1.

   o  The BRSKI-MASA TLS connection is pledge requests and validates a 'normal' TLS connection
   appropriate for HTTPS voucher using the new REST interfaces.
      calls described below.

   o  The registrar initiates the
   connection and uses pledge completes authentication of the MASA URL obtained server certificate as described
      detailed in Section 2.8. 5.6.1.  This moves the BRSKI-EST TLS
      connection out of the provisional state.

   o  Mandatory bootstrap steps conclude with voucher status telemetry
      (see Section 5.7).

   The mechanisms in [RFC6125] SHOULD BRSKI-EST TLS connection can now be used
   authentication of the MASA.  Some vendors will establish explicit (or
   private) trust anchors for validating their MASA; this will typically
   done as part of a sales channel integration.  Registars SHOULD permit
   trust anchors to be pre-configured on a per-vendor basis. EST enrollment.

   The primary method of extensions for a registrar "authentication" by the MASA (equivalent to EST server) are:

   o  Client authentication is
   detailed in Section 5.5.  As detailed in Section 11 automated using Initial Device Identity
      (IDevID) as per the MASA might
   find it necessary to request additional registrar EST certificate based client authentication.
      The MASA and subject field's DN encoding MUST include the registrars SHOULD be prepared to support TLS client
   certificate authentication and/or HTTP Basic or Digest authentication "serialNumber"
      attribute with the device's unique serial number as described explained in [RFC7030] for EST clients.  This connection MAY also
   have no client authentication at all (Section 7.4)
      Section 2.3.1

   o  The authentication of registrar requests and validates the BRSKI-MASA connection does not affect voucher from the
   voucher-request process, as voucher-requests are already signed by MASA.

   o  The registrar forwards the registrar.  Instead, this authentication provides access control voucher to the audit log.

   Implementors are advised that contacting the MASA is pledge when requested.

   o  The registrar performs log verifications in addition to establish a
   secured REST local
      authorization checks before accepting optional pledge device
      enrollment requests.

5.1.  BRSKI-EST TLS establishment details

   The pledge establishes the TLS connection with a web service and that there are a
   number of authentication models being explored within the industry.
   Registrars are RECOMMENDED to fail gracefully and generate useful
   administrative notifications or logs in the advent of unexpected HTTP
   401 (Unauthorized) responses from the MASA.

5.5.  Registrar Requests Voucher from MASA

   When a registrar receives a pledge voucher-request it in turn submits
   a registrar voucher-request to through
   the MASA service via an HTTPS RESTful
   interface ([RFC7231]).

   This circuit proxy (see Section 4) but the TLS handshake is done with an HTTP POST using the operation path value of
   "/.well-known/est/requestvoucher".
   registrar.  The voucher media type "application/voucher-cms+json" BRSKI-EST pledge is defined in
   [RFC8366] the TLS client and is also used for the BRSKI-EST
   registrar voucher-request.  It is
   a JSON document that has been signed using a CMS structure.  The
   registrar MUST sign the registrar voucher-request.  The entire
   registrar certificate chain, up to and including TLS server.  All security associations established
   are between the Domain CA, MUST
   be included in pledge and the CMS structure.

   MASA impementations SHOULD anticipate future media types but registrar regardless of proxy
   operations.

   Establishment of
   course will simply fail the request if those types are not yet known.

   The Registrar SHOULD include an [RFC7231] BRSKI-EST TLS connection is as specified in EST
   [RFC7030] section 5.3.2 "Accept"
   header field indicating 4.1.1 "Bootstrap Distribution of CA Certificates"
   [RFC7030] wherein the response media types that are acceptable.
   This list SHOULD be client is authenticated with the entire list presented to IDevID
   certificate, and the Registrar EST server (the registrar) is provisionally
   authenticated with an unverified server certificate.

   The signatures in the
   Pledge's original request (see Section 5.2) but MAY certificate MUST be validated even if a subset.
   MASA's are expected to signing
   key can not (yet) be flexible in what they accept. validated.  The registrar populates certificate (or chain) MUST be
   retained for later validation.

   A self-signed certificate for the voucher-request fields Registrar is acceptable as follows:

   created-on:  The Registrars SHOULD populate this field with the
      current date and time when the Registrar formed this
   voucher
      request.  This field provides additional information to will validate it.

   [RFC5280] section 4.2.1.2 does not mandate that the MASA.

   nonce:  This
   SubjectKeyIdentifier extension be present in non-CA certificates.  It
   is RECOMMENDED that Registrar certificates (even if self-signed),
   always include the value from the pledge voucher-request.  The
      registrar voucher-request MAY omit the nonce SubjectKeyIdentifier to be used as per Section 3.1)

   serial-number: a DomainID, and
   that a hash stronger than SHA-1 be used.

   The serial number of the pledge the registrar would
      like performs input validation of all data received until a
   voucher for.  The registrar determines this value by
      parsing the authenticated pledge IDevID certificate.  See is verified as specified in Section 2.3.  The registrar MUST verify that 5.6.1 and the serial number
      field it parsed matches TLS
   connection leaves the serial number field provisional state.  Until these operations are
   complete the pledge
      provided in its voucher-request.  This provides a sanity check
      useful for detecting error conditions and logging. could be communicating with an attacker.

   The registrar
      MUST NOT simply copy the serial number field from a pledge voucher
      request as that field is claimed but not certified.

   idevid-issuer:  The idevid-issuer value from code needs to be written with the pledge certificate assumption that all data
   is included being transmitted at this point to ensure an unauthenticated peer, and
   that received data, while inside a unique identity.

   prior-signed-voucher-request:  The signed pledge voucher-request
      SHOULD TLS connection, MUST be included in the registrar voucher-request.  (NOTE: what
      is included is considered
   untrusted.  This particularly applies to HTTP headers and CMS
   structures that make up the complete voucher.

   A pledge voucher-request, inclusive that can connect to multiple registries concurrently SHOULD
   do so.  Some devices may be unable to do so for lack of
      the 'assertion', 'proximity-registrar-cert', etc wrapped threading, or
   resource issues.  Concurrent connections defeat attempts by the
      pledge's original signature).  If a signed voucher-request was not
      received from the pledge then this leaf is omitted
   malicious proxy from the
      registrar voucher request. causing a TCP Slowloris-like attack (see
   [slowloris]).

   A nonceless registrar voucher-request MAY be submitted pledge that can not maintain as many connections as there are
   eligible proxies will need to rotate among the MASA.
   Doing so allows the registrar various choices,
   terminating connections that do not appear to request a voucher when be making progress.  If
   no connection is making progess after 5 seconds then the pledge is
   offline, or when
   SHOULD drop the registrar anticipates not being able to connect oldest connection and go on to a different proxy: the MASA while
   proxy that has been communicated with least recently.  If there were
   no other proxies discovered, the pledge is being deployed.  Some use cases
   require the registrar MAY continue to learn the appropriate IDevID SerialNumber
   field and appropriate 'Accept header field' values wait, as long
   as it is concurrently listening for new proxy announcements.

5.2.  Pledge Requests Voucher from the physical
   device labeling or from Registrar

   When the sales channel (out-of-scope pledge bootstraps it makes a request for this
   document).

   All other fields MAY be omitted in a voucher from a
   registrar.

   This is done with an HTTPS POST using the registrar voucher-request.

   Example JSON payloads of registrar voucher-requests are in
   Section 3.3 Examples 2 through 4. operation path value of
   "/.well-known/est/requestvoucher".

   The MASA verifies pledge voucher-request Content-Type is:

   application/voucher-cms+json  [RFC8366] defines a "YANG-defined JSON
      document that has been signed using a CMS structure", and the registrar
      voucher-request described in Section 3 is internally
   consistent but does not necessarily authenticate the registrar
   certificate since created in the registrar same way.
      The media type is not known to the MASA same as defined in advance.
   The MASA performs the actions [RFC8366].  and validation checks described in is also
      used for the
   following sub-sections before issuing a voucher.

5.5.1.  MASA renewal of expired vouchers

   As described in [RFC8366] vouchers are normally short lived to avoid
   revocation issues.  If pledge voucher-request.  The pledge MUST sign the
      request is for a previous (expired)
   voucher using the same registrar then Section 2.3 credential.

   Registrar implementations SHOULD anticipate future media types but of
   course will simply fail the request for a renewed
   voucher SHOULD be automatically authorized. if those types are not yet known.

   The MASA has sufficient
   information to determine this by examining the request, pledge SHOULD include an [RFC7231] section 5.3.2 "Accept" header
   field indicating the registrar
   authentication, and acceptable media type for the existing audit log.  The issuance of a
   renewed voucher response.
   The "application/voucher-cms+json" media type is logged as detailed defined in [RFC8366]
   but constrained voucher formats are expected in Section 5.6.

   To inform the future.
   Registrars and MASA that existing vouchers are not expected to be renewed one
   can update or revoke flexible in what they accept.

   The pledge populates the registrar credentials used voucher-request fields as follows:

   created-on:  Pledges that have a realtime clock are RECOMMENDED to authorize
      populate this field with the
   request (see Section 5.5.3 and Section 5.5.4).  More flexible methods
   will likely involve sales channel integration current date and authorizations
   (details are out-of-scope of time in yang:date-
      and-time format.  This provides additional information to the
      MASA.  Pledges that have no real-time clocks MAY omit this document).

5.5.2.  MASA verification of field.

   nonce:  The pledge voucher-request signature consistency MUST contain a cryptographically
      strong random or pseudo-random number nonce. (see [RFC4086]) Doing
      so ensures Section 2.6.1 functionality.  The MASA nonce MUST verify that the NOT be
      reused for multiple bootstrapping attempts.  (The registrar
      voucher-request is signed by MAY omit the nonce as per Section 3.1)

   proximity-registrar-cert:  In a registrar.  This pledge voucher-request this is confirmed by verifying that the id-kp-cmcRA
   extended key usage extension field (as detailed in EST RFC7030
   section 3.6.1) exists in the
      first certificate of in the entity that signed TLS server 'certificate_list' sequence
      (see [RFC5246]) presented by the registrar voucher-request.  This verification is only a
   consistency check that to the unauthenticated domain CA intended pledge.  That
      is, it is the
   voucher-request signer to end-entity certificate.  This MUST be populated in a registrar.  Performing this check
   provides value to the domain PKI by assuring the domain administrator
   that the MASA service will only respect claims from authorized
   Registration Authorities of the domain.

   The MASA verifies that
      pledge voucher-request if the domain CA certificate "proximity" assertion is included populated.

   All other fields MAY be omitted in the
   CMS structure as detailed in Section 5.5.

5.5.3.  MASA authentication pledge voucher-request.

   An example JSON payload of registrar (certificate)

   If a nonceless pledge voucher-request is submitted the MASA MUST
   authenticate the in Section 3.3
   Example 1.

   The registrar validates the client identity as described in either EST
   [RFC7030] section 3.2, section 3.3, or by validating the registrar's
   certificate used to sign the 3.3.2.

   The registrar voucher-request.  Any of these
   methods reduce confirms that the risk of DDoS attacks assertion is 'proximity' and provide an authenticated
   identity as an input to sales channel integration that
   pinned 'proximity-registrar-cert' is the Registrar's certificate.  If
   this validation fails, then there a On-Path Attacker (MITM), and authorizations
   (details are out-of-scope the
   connection MUST be closed after the returning an HTTP 401 error code.

5.3.  Registrar Authorization of this document). Pledge

   In a fully automated network all devices must be securely identified
   and authorized to join the nonced case, validation of domain.

   A Registrar accepts or declines a request to join the registrar MAY be omitted if domain, based
   on the authenticated identity presented.  For different networks,
   examples of Automated acceptance may include:

   o  allow any device policy is to accept audit-only vouchers.

5.5.4.  MASA revocation checking of registrar (certificate)

   As noted in Section 5.5.3 a specific type (as determined by the MASA performs registrar authentication
   in X.509
      IDevID),

   o  allow any device from a subset of situations (e.g. nonceless voucher requests).  Normal
   PKIX revocation checking is assumed during either EST client
   authentication or voucher-request signature validation.  Similarly,
   as noted in Section 5.5.2, specific vendor (as determined by the MASA performs normal PKIX revocation
   checking during signature consistency checks (a signature
      X.509 IDevID),

   o  allow a specific device from a vendor (as determined by the X.509
      IDevID) against a
   registrar certificate that has been revoked domain white list.  (The mechanism for checking
      a shared white list potentially used by multiple Registrars is an inconsistency).

5.5.5.  MASA verification out
      of pledge prior-signed-voucher-request

   The MASA MAY verify that scope).

   If validation fails the registrar voucher-request includes the
   'prior-signed-voucher-request' field. SHOULD respond with the HTTP 404
   error code.  If so the prior-signed- voucher-request MUST include a 'proximity-registrar-cert' that is
   consistent in an unknown format, then an
   HTTP 406 error code is more appropriate.  A situation that could be
   resolved with the certificate used administrative action (such as adding a vendor to sign a
   whitelist) MAY be responded with an 403 HTTP error code.

   If authorization is successful the registrar voucher-
   request.  Additionally the voucher-request serial-number leaf MUST
   match the pledge serial-number that the MASA extracts obtains a voucher from
   the
   signing certificate of the prior-signed-voucher-request.  The MASA is
   aware of which pledges support signing of their voucher requests service (see Section 5.5) and
   can use this information returns that MASA signed
   voucher to confirm proximity of the pledge with the
   registrar, thus ensuring that the BRSKI-EST as described in Section 5.6.

5.4.  BRSKI-MASA TLS establishment details

   The BRSKI-MASA TLS connection has no
   man-in-the-middle.

   If these checks succeed the MASA updates is a 'normal' TLS connection
   appropriate for HTTPS REST interfaces.  The registrar initiates the voucher
   connection and audit log
   assertion leafs with uses the "proximity" assertion.

5.5.6. MASA pinning of registrar

   The registrar's certificate chain is extracted from the signature
   method.  The chain includes the domain CA certificate URL obtained as specified described in
   Section 5.5.  This certificate is 2.8.  The mechanisms in [RFC6125] SHOULD be used to populate the "pinned-
   domain-cert"
   authentication of the voucher being issued.  The domainID (e.g., hash MASA.  Some vendors will establish explicit (or
   private) trust anchors for validating their MASA; this will typically
   done as part of a sales channel integration.

   As described in [RFC7030], the root public key) is determined from the pinned-domain-cert MASA and
   is used to update the audit log.

5.5.7.  MASA nonce handling

   The MASA does not verify the nonce itself.  If the registrar voucher-
   request contains registrars SHOULD be
   prepared to support TLS client certificate authentication and/or HTTP
   Basic or Digest authentication.  This connection MAY also have no
   client authentication at all.

   Registars SHOULD permit trust anchors to be pre-configured on a nonce, and the prior-signed-voucher-request
   exists, then the MASA MUST verify that the nonce is consistent.
   (Recall from above that per-
   vendor(MASA) basis.  Registrars SHOULD include the voucher-request might not contain ability to
   configure a
   nonce, see Section 5.5 TLS ClientCertificate on a per-MASA basis, or to use no
   client certificate.  Registrars SHOULD also permit an HTTP Basic and Section 5.5.3).
   Digest authentication to be configured.

   The MASA MUST use authentication of the nonce from BRSKI-MASA connection does not change the registrar
   voucher-request for process, as voucher-requests are already signed by
   the resulting voucher and audit log.  The prior-signed-voucher-
   request nonce is ignored during registrar.  Instead, this operation.

5.6.  MASA and Registrar Voucher Response

   The MASA voucher response to the registrar is forwarded without
   changes authentication provides access control
   to the pledge; therefore this section applies to both audit log.

   Implementors are advised that contacting the MASA is to establish a
   secured REST connection with a web service and that there are a
   number of authentication models being explored within the registrar.  The HTTP signaling described applies industry.
   Registrars are RECOMMENDED to both
   the MASA fail gracefully and registrar responses.  A registrar either caches prior
   MASA responses or dynamically requests a new voucher based on local
   policy (it does not generate useful
   administrative notifications or sign a voucher).  Registrar
   evaluation logs in the advent of unexpected HTTP
   401 (Unauthorized) responses from the voucher itself is purely for transparency and audit
   purposes to further inform log verification (see Section 5.8.2) and
   therefore a registrar could accept future voucher formats MASA.

5.4.1.  MASA authentication of customer Registrar

   Providing per-customer options requires that are
   opaque to the registrar.

   If the voucher-request is successful, the server (MASA responding to customer's registrar or registrar responding to pledge) response MUST contain an
   HTTP 200 response code.  The server MUST answer
   be uniquely identified.  This can be done by any stateless method
   that HTTPS supports: such as with HTTP Basic or Digest authentication
   (that is using a suitable 4xx password), but the use of TLS Client Certificate
   authentication is RECOMMENDED.

   Stateful methods involving API tokens, or 5xx HTTP [RFC7230] error code when a problem occurs.  In this
   case, Cookies are not
   recommended.

   It is expected that the response data from setup and configuration of per-customer
   Client Certificates is done as part of a sales ordering process.

   The use of public PKI (i.e.  WebPKI) End-Entity Certificates to
   identify the Registrar is reasonable, and if done universally this
   would permit a MASA MUST be to identify a plaintext human-
   readable (ASCII, English) error message containing explanatory
   information describing why the request was rejected. customers' Registrar simply by a
   FQDN.

   The registrar MAY respond with an HTTP 202 ("the request has been
   accepted for processing, use of DANE records in DNSSEC signed zones would also permit use
   of a FQDN to identify customer Registrars.

   A third (and simplest, but least flexible) mechanism would be for the processing has not been completed")
   MASA to simply store the Registrar's certificate pinned in a
   database.

   A MASA without any supply chain integration can simply accept
   Registrars without any authentication, or can accept them on a blind
   Trust-on-First-Use basis as described in EST [RFC7030] section 4.2.3 wherein the client "MUST
   wait at least the specified 'Retry-After' time before repeating Section 7.4.2.

   This document does not make a specific recommendation as there is
   likely different trade offs in different environments and product
   values.  Even within the
   same request".  (see [RFC7231] section 6.6.4) The pledge ANIMA ACP applicability, there is
   RECOMMENDED to provide local feedback (blinked LED etc) during this
   wait cycle if mechanisms a
   significant difference between supply chain logistics for this are available.  To prevent an
   attacker registrar $100 CPE
   devices and $100,000 core routers.

5.5.  Registrar Requests Voucher from significantly delaying bootstrapping the
   pledge MUST limit the 'Retry-After' time to 60 seconds.  Ideally the
   pledge would keep track of the appropriate Retry-After header field
   values for any number of outstanding registrars but this would
   involve MASA

   When a registrar receives a state table on the pledge.  Instead the pledge MAY ignore
   the exact Retry-After value voucher-request it in favor of turn submits
   a single hard coded value (a registrar that is unable voucher-request to complete the transaction after the first
   60 seconds has another chance a minute later).  A pledge SHOULD only
   maintain a 202 retry-state for up to 4 days, which MASA service via an HTTPS
   interface ([RFC7231]).

   This is longer than a
   long weekend, after which time done with an HTTP POST using the enrollment attempt fails operation path value of
   "/.well-known/est/requestvoucher".

   The voucher media type "application/voucher-cms+json" is defined in
   [RFC8366] and is also used for the
   pledge returns to discovery state.

   In order to avoid infinite redirect loops, which registrar voucher-request.  It is
   a malicious JSON document that has been signed using a CMS structure.  The
   registrar might do in order to keep the pledge from discovering MUST sign the
   correct registrar, registrar voucher-request.  The entire
   registrar certificate chain, up to and including the pledge Domain CA, MUST NOT follow more than one
   redirection (3xx code) to another web origins.  EST supports
   redirection
   be included in the CMS structure.

   MASA impementations SHOULD anticipate future media types but requires user input; this change allows of
   course will simply fail the pledge to
   follow a single redirection without a user interaction.

   A 403 (Forbidden) response is appropriate request if the voucher-request is those types are not signed correctly, stale, or if yet known.

   The Registrar SHOULD include an [RFC7231] section 5.3.2 "Accept"
   header field indicating the pledge has another outstanding
   voucher response media types that cannot are acceptable.
   This list SHOULD be overridden.

   A 404 (Not Found) response is appropriate when the request is for a
   device that is not known entire list presented to the MASA.

   A 406 (Not Acceptable) response is appropriate if a voucher of Registrar in the
   desired type or using
   Pledge's original request (see Section 5.2) but MAY be a subset.
   MASA's are expected to be flexible in what they accept.

   The registrar populates the desired algorithms (as indicated by voucher-request fields as follows:

   created-on:  The Registrars SHOULD populate this field with the
   Accept: header fields,
      current date and algorithms used in time when the signature) cannot
   be issued such as because Registrar formed this voucher
      request.  This field provides additional information to the MASA knows MASA.

   nonce:  This value, if present, is copied from the pledge cannot process
   that type. voucher-
      request.  The registrar SHOULD use this response if it determines voucher-request MAY omit the nonce as per
      Section 3.1.

   serial-number:  The serial number of the pledge is unacceptable due to inventory control, MASA audit logs,
   or any other reason.

   A 415 (Unsupported Media Type) response is appropriate for the registrar would
      like a request voucher for.  The registrar determines this value by
      parsing the authenticated pledge IDevID certificate.  See
      Section 2.3.  The registrar MUST verify that has the serial number
      field it parsed matches the serial number field the pledge
      provided in its voucher-request.  This provides a voucher-request or accept encoding sanity check
      useful for detecting error conditions and logging.  The registrar
      MUST NOT simply copy the serial number field from a pledge voucher
      request as that field is claimed but not understood. certified.

   idevid-issuer:  The voucher response format is as indicated in the submitted Accept
   header fields or based on Issuer value from the MASA's prior understanding of proper
   format for this Pledge.  Only value from the [RFC8366] "application/voucher-
   cms+json" media type pledge
      IDevID certificate is defined at this time.  The syntactic details
   of vouchers are described in detail in [RFC8366].  Figure 8 shows included to ensure a
   sample uniqueness of the contents
      serial-number.  In the case of a voucher.

   {
     "ietf-voucher:voucher": {
       "nonce": "62a2e7693d82fcda2624de58fb6722e5",
       "assertion": "logging",
       "pinned-domain-cert": "base64encodedvalue==",
       "serial-number": "JADA123456789"
     }
   }

   Figure 8: An example voucher

                       Figure 1: An example voucher

   The MASA populates nonceless (offline) voucher-
      request, then an appropriate value needs to be configured from the voucher fields
      same out-of-band source as follows:

   nonce:  The nonce from the pledge if available.  See Section 5.5.7.

   assertion: serial-number.

   prior-signed-voucher-request:  The method used to verify assertion.  See Section 5.5.5.

   pinned-domain-cert: signed pledge voucher-request
      SHOULD be included in the registrar voucher-request.  The domain CA cert.  See Section 5.5.6.  This
      figure entire
      CMS signed structure is illustrative, for an example, see Appendix D.2

   serial-number:  The serial-number as provided in the voucher-request.
      Also see Section 5.5.5.

   domain-cert-revocation-checks:  Set as appropriate to be included, base64 encoded for the pledge's
      capabilities and as documented
      transport in [RFC8366].  The MASA the JSON structure.

   A nonceless registrar voucher-request MAY set
      this field to 'false' since setting it to 'true' would require
      that revocation information be available submitted to the pledge and this
      document does not make normative requirements for [RFC6961] or
      equivalent integrations.

   expires-on:  This is set for nonceless vouchers.  The MASA ensures MASA.
   Doing so allows the registrar to request a voucher lifetime when the pledge is consistent with any revocation
   offline, or pinned-
      domain-cert consistency checks when the pledge might perform.  See
      section Section 2.6.1.  There are three times registrar anticipates not being able to connect
   to consider: (a) a
      configured voucher lifetime in the MASA, (b) MASA while the expiry time for pledge is being deployed.  Some use cases
   require the registrar's certificate, (c) any certificate revocation
      information (CRL) lifetime.  The expires-on registrar to learn the appropriate IDevID SerialNumber
   field SHOULD and appropriate 'Accept header field' values from the physical
   device labeling or from the sales channel (out-of-scope for this
   document).

   All other fields MAY be before omitted in the earliest registrar voucher-request.

   Example JSON payloads of these three values.  Typically (b) will be some
      significant time registrar voucher-requests are in
   Section 3.3 Examples 2 through 4.

   The MASA verifies that the future, registrar voucher-request is internally
   consistent but (c) will typically be short
      (on does not necessarily authenticate the order of a week or less).  The RECOMMENDED period for (a) registrar
   certificate since the registrar is on not known to the order of 20 minutes, so it will typically determine MASA in advance.
   The MASA performs the
      lifespan of actions and validation checks described in the resulting
   following sub-sections before issuing a voucher.  20 minutes is sufficient time
      to reach the post-provisional state

5.5.1.  MASA renewal of expired vouchers

   As described in [RFC8366] vouchers are normally short lived to avoid
   revocation issues.  If the pledge, at which point
      there request is an established trust relationship between pledge and
      registrar.  The subsequent operations can take as long as required
      from that point onwards.  The lifetime of for a previous (expired)
   voucher using the same registrar then the request for a renewed
   voucher SHOULD be automatically authorized.  The MASA has no
      impact on sufficient
   information to determine this by examining the lifespan of request, the ownership relationship.

   Whenever registrar
   authentication, and the existing audit log.  The issuance of a
   renewed voucher is issued logged as detailed in Section 5.6.

   To inform the MASA MUST that existing vouchers are not to be renewed one
   can update or revoke the audit log
   appropriately.  The internal state requirements registrar credentials used to maintain authorize the audit
   log are out-of-scope.  See
   request (see Section 5.8.1 for a discussion 5.5.3 and Section 5.5.4).  More flexible methods
   will likely involve sales channel integration and authorizations
   (details are out-of-scope of
   reporting the log to a registrar.

5.6.1.  Pledge voucher this document).

5.5.2.  MASA verification of voucher-request signature consistency

   The pledge MASA MUST verify that the voucher signature using the manufacturer
   installed trust anchor(s) associated with the manufacturer's MASA
   (this registrar voucher-request is likely included in the pledge's firmware).  Management of
   the manufacturer installed trust anchor(s) signed by
   a registrar.  This is out-of-scope of this
   document; this protocol does not update these trust anchor(s).

   The pledge MUST verify confirmed by verifying that the serial-number id-kp-cmcRA
   extended key usage extension field of (as detailed in EST RFC7030
   section 3.6.1) exists in the signed voucher
   matches certificate of the pledge's own serial-number.

   The pledge MUST verify entity that signed
   the voucher nonce field registrar voucher-request.  This verification is accurate and
   matches only a
   consistency check that the nonce unauthenticated domain CA intended the pledge submitted
   voucher-request signer to this registrar, or that the
   voucher is nonceless (see Section 7.2).

   The pledge MUST be prepared to parse and fail gracefully from a
   voucher response that does not contain a 'pinned-domain-cert' field.
   The pledge MUST be prepared registrar.  Performing this check
   provides value to ignore additional fields that it does
   not recognize.

5.6.2.  Pledge authentication of provisional TLS connection

   The 'pinned-domain-cert' element of the voucher contains domain PKI by assuring the domain
   CA's public key.  The pledge MUST use administrator
   that the 'pinned-domain-cert' trust
   anchor to immediately complete authentication MASA service will only respect claims from authorized
   Registration Authorities of the provisional TLS
   connection. domain.

5.5.3.  MASA authentication of registrar (certificate)

   If a registrar's credentials cannot be verified using nonceless voucher-request is submitted the pinned-
   domain-cert trust anchor from MASA MUST
   authenticate the voucher then registrar as described in either EST [RFC7030]
   section 3.2.3, section 3.3.2, or by validating the TLS connection is
   immediately discarded and registrar's
   certificate used to sign the pledge abandons attempts registrar voucher-request.  Any of these
   methods reduce the risk of DDoS attacks and provide an authenticated
   identity as an input to bootstrap
   with sales channel integration and authorizations
   (details are out-of-scope of this discovered registrar.  The pledge SHOULD send voucher
   status telemetry (described below) before closing the TLS connection.
   The pledge MUST attempt to enroll using any other proxies it has
   found.  It SHOULD return to document).

   In the same proxy again after attempting
   with other proxies.  Attempts should be attempted in nonced case, validation of the exponential
   backoff described earlier.  Attempts SHOULD be repeated as failure
   may Registrar's identity (via TLS
   Client Certificate or HTTP authentication) MAY be omitted if the result
   device policy is to accept audit-only vouchers.

5.5.4.  MASA revocation checking of a temporary inconsistently (an inconsistently
   rolled registrar key, or some other mis-configuration).  The
   inconsistently could also be the result an active MITM attack on (certificate)

   As noted in Section 5.5.3 the
   EST connection.

   The MASA performs registrar MUST use authentication
   in a certificate that chains to the pinned-
   domain-cert as its TLS server certificate.

   The pledge's PKIX path validation subset of a registrar certificate's
   validity period information situations (e.g. nonceless voucher requests).  Normal
   PKIX revocation checking is assumed during either EST client
   authentication or voucher-request signature validation.  Similarly,
   as described noted in Section 2.6.1.  Once 5.5.2, the MASA performs normal PKIX path validation is successful the TLS connection revocation
   checking during signature consistency checks (a signature by a
   registrar certificate that has been revoked is no
   longer provisional. an inconsistency).

5.5.5.  MASA verification of pledge prior-signed-voucher-request

   The pinned-domain-cert MASA MAY be installed as an trust anchor for future
   operations such as enrollment (e.g.  [RFC7030] as recommended) or
   trust anchor management or raw protocols that do not need full PKI
   based key management.  It can be used to authenticate any dynamically
   discovered EST server verify that contain the id-kp-cmcRA extended key usage
   extension as detailed in EST RFC7030 section 3.6.1; but to reduce
   system complexity registrar voucher-request includes the pledge SHOULD avoid additional discovery
   operations.  Instead
   'prior-signed-voucher-request' field.  If so the pledge SHOULD communicate directly prior-signed-
   voucher-request MUST include a 'proximity-registrar-cert' that is
   consistent with the certificate used to sign the registrar as voucher-
   request.  Additionally the EST server.  The 'pinned-domain-cert' is not a
   complete distribution voucher-request serial-number leaf MUST
   match the pledge serial-number that the MASA extracts from the
   signing certificate of the [RFC7030] section 4.1.3 CA Certificate
   Response, which is an additional justification for prior-signed-voucher-request.

   If these checks succeed the recommendation
   to proceed MASA updates the voucher and audit log
   assertion leafs with EST key management operations.  Once a full CA
   Certificate Response is obtained it is more authoritative for the
   domain than "proximity" assertion.

5.5.6.  MASA pinning of registrar

   The registrar's certificate chain is extracted from the limited 'pinned-domain-cert' response.

5.7.  Pledge BRSKI Status Telemetry signature
   method.  The chain includes the domain CA certificate as specified in
   Section 5.5.2.  This certificate is expected to provide indications used to populate the system
   administrators concerning device lifecycle status.  To facilitate
   this it needs telemetry information concerning "pinned-
   domain-cert" of the device's status.

   To indicate pledge status regarding voucher being issued.  The domainID (e.g., hash
   of the voucher, root public key) is determined from the pledge MUST post
   a status message pinned-domain-cert and
   is used to update the Registrar.

   The posted data media type: application/json audit log.

5.5.7.  MASA nonce handling

   The client HTTP POSTs the following to MASA does not verify the server at nonce itself.  If the EST well
   known URI "/voucher_status".

   The format registrar voucher-
   request contains a nonce, and semantics described below are for version 1.  A
   version field is included to permit significant changes to this
   feedback in the future.  A Registrar prior-signed-voucher-request
   exists, then the MASA MUST verify that receives a status message
   with a version larger than it knows about SHOULD log the contents and
   alert nonce is consistent.
   (Recall from above that the voucher-request might not contain a human.
   nonce, see Section 5.5 and Section 5.5.3).

   The Status field indicates if MASA populates the voucher audit-log with the nonce that was acceptable.  Boolean
   values are acceptable. verified.
   If a nonceless voucher is issued, then the audit log is to be
   populated with the JSON value "null".

5.6.  MASA and Registrar Voucher Response

   The MASA voucher was not acceptable response to the Reason string indicates why.
   In registrar is forwarded without
   changes to the failure case pledge; therefore this message may be sent section applies to an unauthenticated,
   potentially malicious registrar both the
   MASA and therefore the Reason string
   SHOULD NOT provide information beneficial to an attacker. registrar.  The
   operational benefit of this telemetry information is balanced against HTTP signaling described applies to both
   the operational costs of not recording that an MASA and registrar responses.

   When a voucher was ignored by request arrives at the registrar, if it has a client cached
   response from the MASA for the corresponding registrar expected voucher-
   request, that cached response can be used according to continue joining local policy;
   otherwise the domain.

   The reason-context attribute is an arbitrary JSON object (literal
   value or hash of values) which provides additional information
   specific registrar constructs a new registrar voucher-request
   and sends it to this pledge.  The contents the MASA.

   Registrar evaluation of this field are not subject
   to standardization.

   The version, the voucher itself is purely for transparency
   and status fields MUST be present.  The Reason field
   SHOULD be present whenever the status field is negative.  The Reason-
   Context field is optional.

   The keys audit purposes to this JSON hash further inform log verification (see
   Section 5.8.2) and therefore a registrar could accept future voucher
   formats that are case-insensitive.  Figure 2 shows an
   example JSON.

   {
       "version":"1",
       "status":false,
       "reason":"Informative human readable message",
       "reason-context": { "additional" : "JSON" }
   }

                    Figure 2: Example Status Telemetry

   The opaque to the registrar.

   If the voucher-request is successful, the server SHOULD respond with (MASA responding to
   registrar or registrar responding to pledge) response MUST contain an
   HTTP 200 but MAY simply fail with
   an HTTP 404 error. response code.  The client ignores any response.  Within the server logs the server SHOULD capture this telemetry information.

   Additional standard JSON fields in MUST answer with a suitable 4xx
   or 5xx HTTP [RFC7230] error code when a problem occurs.  In this POST MAY be added, see
   Section 8.3.  A server that sees unknown fields should log them, but
   otherwise ignore them.

5.8.  Registrar audit log request

   After receiving the pledge status telemetry Section 5.7, the
   registrar SHOULD request
   case, the MASA audit log response data from the MASA service.

   This is done with an HTTP POST using MUST be a plaintext human-
   readable (ASCII, English) error message containing explanatory
   information describing why the operation path value of
   "/.well-known/est/requestauditlog". request was rejected.

   The registrar SHOULD MAY respond with an HTTP POST 202 ("the request has been
   accepted for processing, but the same registrar voucher-request processing has not been completed")
   as
   it did when requesting a voucher (using the same Content-Type).  It
   is posted to the /requestauditlog URI instead.  The "idevid-issuer"
   and "serial-number" informs the MASA which log is requested so described in EST [RFC7030] section 4.2.3 wherein the
   appropriate log can be prepared for client "MUST
   wait at least the response.  Using specified 'Retry-After' time before repeating the
   same
   media type and message minimizes cryptographic and message operations
   although it results in additional network traffic. request".  (see [RFC7231] section 6.6.4) The relying MASA
   implementation MAY leverage internal state pledge is
   RECOMMENDED to associate provide local feedback (blinked LED etc) during this request
   with the original, and by now already validated, voucher-request so
   as to avoid
   wait cycle if mechanisms for this are available.  To prevent an extra crypto validation.

   A
   attacker registrar MAY request logs at future times.  If from significantly delaying bootstrapping the registrar
   generates a new request then
   pledge MUST limit the MASA is forced 'Retry-After' time to perform 60 seconds.  Ideally the
   additional cryptographic operations to verify
   pledge would keep track of the new request.

   A MASA that receives a request appropriate Retry-After header field
   values for any number of outstanding registrars but this would
   involve a device that does not exist, or
   for which state table on the requesting owner was never an owner returns an HTTP 404
   ("Not found") code.

   Rather than returning pledge.  Instead the audit log as pledge MAY ignore
   the exact Retry-After value in favor of a response single hard coded value (a
   registrar that is unable to complete the POST (with a
   return code 200), transaction after the MASA MAY instead return a 201 ("Created")
   RESTful response ([RFC7231] sections 6.3.2 and 7.1) containing first
   60 seconds has another chance a URL
   to the prepared (and easily cachable) audit response.

   In order to avoid enumeration of device audit logs, MASA that return
   URLs minute later).  A pledge SHOULD take care only
   maintain a 202 retry-state for up to make the returned URL unguessable.  For
   instance, rather 4 days, which is longer than returning URLs containing a database number
   such as https://example.com/auditlog/1234 or the EUI of
   long weekend, after which time the device
   such https://example.com/auditlog/10-00-00-11-22-33, enrollment attempt fails and the MASA SHOULD
   return a randomly generated value (a "slug" in web parlance).  The
   value is used
   pledge returns to find the relevant database entry. discovery state.

   A MASA pledge that returns retries a code 200 MAY also include request after receiving a Location: header
   for future reference by the registrar.

5.8.1.  MASA audit log response

   A log data file is returned consisting of all log entries associated
   with the device selected by the IDevID presented in 202 message MUST
   resend the request.  The
   audit log may be abridged by removal of old or repeated values as
   explained below.  The returned data is in JSON format ([RFC7951]), same voucher-request.  It MUST NOT sign a new voucher-
   request each time, and in particular, it MUST NOT change the Content-Type SHOULD be "application/json".  For example:

 {
   "version":"1",
   "events":[
     {
         "date":"<date/time of the entry>",
         "domainID":"<domainID extracted from voucher-request>",
         "nonce":"<any nonce if supplied (or
   value.

   In order to avoid infinite redirect loops, which a malicious
   registrar might do in order to keep the exact string 'NULL')>",
         "assertion":"<the value pledge from discovering the voucher assertion leaf>",
         "truncated":"<the number of domainID entries truncated>"
     },
     {
         "date":"<date/time of the entry>",
         "domainID":"<anotherDomainID extracted from voucher-request>",
         "nonce":"<any nonce if supplied (or
   correct registrar, the exact string 'NULL')>",
         "assertion":"<the value from pledge MUST NOT follow more than one
   redirection (3xx code) to another web origins.  EST supports
   redirection but requires user input; this change allows the voucher assertion leaf>"
     }
   ],
     "truncation": {
         "nonced duplicates": "<total number of entries truncated>",
         "nonceless duplicates": "<total number of entries truncated>",
         "arbitrary": "<number of domainID entries removed entirely>"
      }
 }

                  Figure 3: Example of audit-log response

   Distribution of pledge to
   follow a large log single redirection without a user interaction.

   A 403 (Forbidden) response is less than ideal.  This structure can
   be optimized as follows: Nonced appropriate if the voucher-request is
   not signed correctly, stale, or Nonceless entries for if the same
   domainID MAY pledge has another outstanding
   voucher that cannot be abridged from the log leaving only overridden.

   A 404 (Not Found) response is appropriate when the single most
   recent nonced or nonceless entry request is for a
   device that domainID.  In the case of
   truncation is not known to the 'event' truncation value SHOULD contain MASA.

   A 406 (Not Acceptable) response is appropriate if a count voucher of the
   number of events for this domainID that were omitted.  The log SHOULD
   NOT be further reduced but there could exist operational situation
   where maintaining
   desired type or using the full log is not possible.  In such situations desired algorithms (as indicated by the log MAY be arbitrarily abridged for length, with
   Accept: header fields, and algorithms used in the number of
   removed entries indicated signature) cannot
   be issued such as 'arbitrary'.

   If the truncation count exceeds 1024 then because the MASA MAY knows the pledge cannot process
   that type.  The registrar SHOULD use this value
   without further incrementing it.

   A log where duplicate entries for response if it determines
   the same domain have been omitted
   ("nonced duplicates" and/or "nonceless duplicates) could still be
   acceptable for informed decisions. pledge is unacceptable due to inventory control, MASA audit logs,
   or any other reason.

   A log 415 (Unsupported Media Type) response is appropriate for a request
   that has had "arbitrary"
   truncations is less acceptable but manufacturer transparency is
   better than hidden truncations.

   This document specifies a simple log voucher-request or Accept: value that is not understood.

   The voucher response format is as provided by the MASA
   service to indicated in the registrar.  This format could be improved by
   distributed consensus technologies that integrate vouchers with
   technologies such as block-chain or hash trees submitted Accept
   header fields or optimized logging
   approaches.  Doing so is out of based on the scope MASA's prior understanding of this document but is an
   anticipated improvement proper
   format for future work.  As such, the registrar
   client SHOULD anticipate new kinds of responses, and SHOULD provide
   operator controls to indicate how to process unknown responses.

5.8.2.  Registrar audit log verification

   Each time the Manufacturer Authorized Signing Authority (MASA) issues
   a voucher, it appends details of this Pledge.  Only the assignment to an internal audit
   log for that device.  The internal audit log [RFC8366] "application/voucher-
   cms+json" media type is processed when
   responding to requests for defined at this time.  The syntactic details as
   of vouchers are described in Section 5.8.  The
   contents of the audit log can express detail in [RFC8366].  Figure 14 shows a variety
   sample of trust levels, and
   this section explains what kind the contents of trust a registrar can derive from
   the entries.

   While the audit log provides a list of vouchers that were issued by voucher.

   {
     "ietf-voucher:voucher": {
       "nonce": "62a2e7693d82fcda2624de58fb6722e5",
       "assertion": "logging",
       "pinned-domain-cert": "base64encodedvalue==",
       "serial-number": "JADA123456789"
     }
   }

                       Figure 14: An example voucher

   The MASA populates the MASA, voucher fields as follows:

   nonce:  The nonce from the vouchers are issued in response pledge if available.  See Section 5.5.7.

   assertion:  The method used to voucher-requests, verify the relationship between pledge
      and it registrar.  See Section 5.5.5.

   pinned-domain-cert:  The domain CA cert.  See Section 5.5.6.  This
      figure is the contents of the voucher-requests which determines how
   meaningful the audit log entries are.

   A registrar SHOULD use the log information to make illustrative, for an informed
   decision regarding example, see Appendix D.2

   serial-number:  The serial-number as provided in the continued bootstrapping of voucher-request.
      Also see Section 5.5.5.

   domain-cert-revocation-checks:  Set as appropriate for the pledge. pledge's
      capabilities and as documented in [RFC8366].  The
   exact policy is out of scope of MASA MAY set
      this document as field to 'false' since setting it depends on the
   security requirements within the registrar domain.  Equipment to 'true' would require
      that is
   purchased pre-owned can revocation information be expected available to have an extensive history. the pledge and this
      document does not make normative requirements for [RFC6961] or
      equivalent integrations.

   expires-on:  This is set for nonceless vouchers.  The following discussion MASA ensures
      the voucher lifetime is provided consistent with any revocation or pinned-
      domain-cert consistency checks the pledge might perform.  See
      section Section 2.6.1.  There are three times to help explain consider: (a) a
      configured voucher lifetime in the value of
   each log element:

   date:  The date field provides MASA, (b) the registrar an opportunity to divide expiry time for
      the log around known events such as registrar's certificate, (c) any certificate revocation
      information (CRL) lifetime.  The expires-on field SHOULD be before
      the purchase date.  Depending
      on context known to earliest of these three values.  Typically (b) will be some
      significant time in the registrar or administrator events before/
      after certain dates can have different levels future, but (c) will typically be short
      (on the order of importance.  For
      example a week or less).  The RECOMMENDED period for equipment that (a)
      is expected to be new, and thus have no
      history, on the order of 20 minutes, so it would be a surprise will typically determine the
      lifespan of the resulting voucher.  20 minutes is sufficient time
      to find prior entries.

   domainID:  If reach the log includes an unexpected domainID then post-provisional state in the pledge
      could have imprinted on pledge, at which point
      there is an unexpected domain. established trust relationship between pledge and
      registrar.  The registrar subsequent operations can
      be expected to use a variety of techniques to define "unexpected"
      ranging take as long as required
      from white lists of prior domains to anomaly detection
      (e.g. "this device was previously bound to a different domain than
      any other device deployed").  Log entries can also be compared
      against local history logs in search that point onwards.  The lifetime of discrepancies (e.g. "this
      device was re-deployed some number the voucher has no
      impact on the lifespan of times internally but the
      external ownership relationship.

   Whenever a voucher is issued the MASA MUST update the audit log shows additional re-deployments our
   appropriately.  The internal
      logs are unaware of").

   nonce:  Nonceless entries mean state requirements to maintain the logged domainID could
      theoretically trigger audit
   log are out-of-scope.  See Section 5.8.1 for a reset discussion of
   reporting the pledge and then take over
      management by using the existing nonceless voucher.

   assertion: log to a registrar.

5.6.1.  Pledge voucher verification

   The assertion leaf in pledge MUST verify the voucher and audit log indicates
      why the MASA issued signature using the voucher.  A "verified" entry means that manufacturer
   installed trust anchor(s) associated with the manufacturer's MASA issued
   (this is likely included in the associated voucher as a result pledge's firmware).  Management of positive
      verification
   the manufacturer installed trust anchor(s) is out-of-scope of ownership but this can still be problematic for
      registrar's that expected only new (not pre-owned) pledges.  A
      "logged" assertion informs the registrar that
   document; this protocol does not update these trust anchor(s).

   The pledge MUST verify the prior vouchers
      were issued with minimal verification.  A "proximity" assertion
      assures serial-number field of the registrar that signed voucher
   matches the pledge's own serial-number.

   The pledge was truly communicating with
      the prior domain and thus provides assurance MUST verify that the prior domain
      really has deployed the pledge.

   A relatively simple policy voucher nonce field is to white list known (internal or
   external) domainIDs accurate and to require all vouchers to have a
   matches the nonce and/ the pledge submitted to this registrar, or require that all the
   voucher is nonceless vouchers (see Section 7.2).

   The pledge MUST be prepared to parse and fail gracefully from a subset (e.g. only
   internal) domainIDs.  A simple action is
   voucher response that does not contain a 'pinned-domain-cert' field.

   Such a thing indicates a failure to revoke any locally issued
   credentials for enroll in this domain, and the
   pledge in question or to refuse to forward the
   voucher.  A registrar MAY MUST attempt joining with other available Join Proxy.

   The pledge MUST be configured prepared to ignore the history of the
   device but it is RECOMMENDED additional fields that this only be configured if hardware
   assisted NEA [RFC5209] is supported.

5.9.  EST Integration for PKI bootstrapping it does
   not recognize.

5.6.2.  Pledge authentication of provisional TLS connection

   The pledge SHOULD follow 'pinned-domain-cert' element of the BRSKI operations with EST enrollment
   operations including "CA Certificates Request", "CSR Attributes" and
   "Client Certificate Request" or "Server-Side Key Generation", etc.
   This is a relatively seamless integration since BRSKI REST calls
   provide an automated alternative to voucher contains the manual bootstrapping method
   described in [RFC7030].  As noted above, domain
   CA's public key.  The pledge MUST use of HTTP 1.1 persistent
   connections simplifies the pledge state machine.

   Although EST allows clients 'pinned-domain-cert' trust
   anchor to obtain multiple certificates by
   sending multiple CSR requests BRSKI mandates use immediately complete authentication of the CSR
   Attributes request and mandates that the registrar validate provisional TLS
   connection.

   If a registrar's credentials cannot be verified using the CSR
   against pinned-
   domain-cert trust anchor from the expected attributes.  This implies that client requests
   will "look voucher then the same" TLS connection is
   immediately discarded and therefore result in a single logical
   certificate being issued even if the client were to make multiple
   requests.  Registrars MAY contain more complex logic but doing so is
   out-of-scope of this specification.  BRSKI does not signal any
   enhancement or restriction pledge abandons attempts to bootstrap
   with this capability.

5.9.1.  EST Distribution of CA Certificates discovered registrar.  The pledge SHOULD request the full EST Distribution of CA
   Certificates message.  See RFC7030, section 4.1.

   This ensures that send voucher
   status telemetry (described below) before closing the TLS connection.
   The pledge MUST attempt to enroll using any other proxies it has
   found.  It SHOULD return to the complete set of current CA
   certificates beyond same proxy again after unsuccessful
   attempts with other proxies.  Attempts should be made repeated at
   intervals according to the pinned-domain-cert (see Section 5.6.1 for a
   discussion of backoff timer described earlier.  Attempts
   SHOULD be repeated as failure may be the limitations inherent in having a single certificate
   instead result of a full CA Certificates response.)  Although these
   limitations are acceptable during initial bootstrapping, they are not
   appropriate for ongoing PKIX end entity certificate validation.

5.9.2.  EST CSR Attributes

   Automated bootstrapping occurs without local administrative
   configuration of the pledge.  In temporary
   inconsistently (an inconsistently rolled registrar key, or some deployments it is plausible
   that other
   mis-configuration).  The inconsistently could also be the pledge generates result an
   active MITM attack on the EST connection.

   The registrar MUST use a certificate request containing only
   identity information known that chains to the pledge (essentially the X.509
   IDevID information) and ultimately receives pinned-
   domain-cert as its TLS server certificate.

   The pledge's PKIX path validation of a certificate containing
   domain specific identity information.  Conceptually the CA has
   complete control over all fields issued registrar certificate's
   validity period information is as described in Section 2.6.1.  Once
   the end entity
   certificate.  Realistically this PKIX path validation is operationally difficult with the
   current status of PKI certificate authority deployments, where successful the
   CSR TLS connection is submitted to the CA via a number of non-standard protocols.
   Even with all standardized protocols used, it could operationally no
   longer provisional.

   The pinned-domain-cert MAY be
   problematic to expect installed as an trust anchor for future
   operations such as enrollment (e.g.  [RFC7030] as recommended) or
   trust anchor management or raw protocols that service specific certificate fields do not need full PKI
   based key management.  It can be
   created by a CA that is likely operated by a group that has no
   insight into different network services/protocols used.  For example,
   the CA could even be outsourced.

   To alleviate these operational difficulties, the pledge MUST request
   the EST "CSR Attributes" from the used to authenticate any dynamically
   discovered EST server and that contain the id-kp-cmcRA extended key usage
   extension as detailed in EST server needs
   to be able RFC7030 section 3.6.1; but to reply with the attributes necessary for use of the
   certificate in its intended protocols/services.  This approach allows
   for minimal CA integrations and instead reduce
   system complexity the local infrastructure (EST
   server) informs pledge SHOULD avoid additional discovery
   operations.  Instead the pledge of SHOULD communicate directly with the proper fields to include in
   registrar as the
   generated CSR.  This approach EST server.  The 'pinned-domain-cert' is beneficial to automated
   bootstrapping in the widest number not a
   complete distribution of environments.

   If the hardwareModuleName in the X.509 IDevID [RFC7030] section 4.1.3 CA Certificate
   Response, which is populated then it
   SHOULD by default be propagated to an additional justification for the LDevID along recommendation
   to proceed with the
   hwSerialNum.  The EST server SHOULD support local policy concerning
   this functionality.

   In networks using key management operations.  Once a full CA
   Certificate Response is obtained it is more authoritative for the BRSKI enrolled certificate to authenticate
   domain than the
   ACP (Autonomic Control Plane), the EST attributes MUST include the
   "ACP information" field.  See
   [I-D.ietf-anima-autonomic-control-plane] for more details. limited 'pinned-domain-cert' response.

5.7.  Pledge BRSKI Status Telemetry

   The registrar MUST also confirm that the resulting CSR is formatted
   as indicated before forwarding the request to a CA.  If the registrar domain is communicating with the CA using a protocol such as full CMC, which
   provides mechanisms expected to override the CSR attributes, then these
   mechanisms MAY be used even if the client ignores CSR Attribute
   guidance.

5.9.3.  EST Client Certificate Request

   The pledge MUST request a new client certificate.  See RFC7030,
   section 4.2.

5.9.4.  Enrollment Status Telemetry

   For automated bootstrapping of devices, the administrative elements
   providing bootstrapping also provide indications to the system
   administrators concerning device lifecycle status.  This might
   include  To facilitate
   this it needs telemetry information concerning attempted bootstrapping messages seen
   by the client, MASA provides logs and status of credential
   enrollment.  [RFC7030] assumes an end user and therefore does not
   include a final success indication back to the server.  This is
   insufficient for automated use cases. device's status.

   To indicate successful enrollment the client SHOULD re-negotiate the
   EST TLS session using pledge status regarding the newly obtained credentials.  This occurs by voucher, the client initiating pledge MUST post
   a new TLS ClientHello status message on to the existing
   TLS connection. Registrar.

   The client MAY simply close the old TLS session and
   start a new one. posted data media type: application/json

   The server MUST support either model.

   In client HTTP POSTs the case of a FAIL, following to the Reason string indicates why server at the most
   recent enrollment failed. URI ".well-
   known/est/voucher_status".

   The SubjectKeyIdentifier format and semantics described below are for version 1.  A
   version field MUST be is included if the enrollment attempt was for a keypair that is locally
   known to permit significant changes to this
   feedback in the client. future.  A Registrar that receives a status message
   with a version larger than it knows about SHOULD log the contents and
   alert a human.

   The Status field indicates if the voucher was acceptable.  Boolean
   values are acceptable.

   If EST /serverkeygen the voucher was used not acceptable the Reason string indicates why.
   In the failure case this message may be sent to an unauthenticated,
   potentially malicious registrar and failed then therefore the field Reason string
   SHOULD NOT provide information beneficial to an attacker.  The
   operational benefit of this telemetry information is omitted from balanced against
   the operational costs of not recording that an voucher was ignored by
   a client the registrar expected to continue joining the domain.

   The reason-context attribute is an arbitrary JSON object (literal
   value or hash of values) which provides additional information
   specific to this pledge.  The contents of this field are not subject
   to standardization.

   The version, and status fields MUST be present.  The Reason field
   SHOULD be present whenever the status telemetry.

   In field is negative.  The Reason-
   Context field is optional.

   The keys to this JSON hash are case-insensitive.  Figure 15 shows an
   example JSON.

   {
       "version":"1",
       "status":false,
       "reason":"Informative human readable message",
       "reason-context": { "additional" : "JSON" }
   }

                    Figure 15: Example Status Telemetry

   The server SHOULD respond with an HTTP 200 but MAY simply fail with
   an HTTP 404 error.  The client ignores any response.  Within the case
   server logs the server SHOULD capture this telemetry information.

   Additional standard JSON fields in this POST MAY be added, see
   Section 8.4.  A server that sees unknown fields should log them, but
   otherwise ignore them.

5.8.  Registrar audit log request

   After receiving the pledge status telemetry Section 5.7, the
   registrar SHOULD request the MASA audit log from the MASA service.

   This is done with an HTTP POST using the operation path value of
   "/.well-known/est/requestauditlog".

   The registrar SHOULD HTTP POST the same registrar voucher-request as
   it did when requesting a voucher (using the same Content-Type).  It
   is posted to the /requestauditlog URI instead.  The "idevid-issuer"
   and "serial-number" informs the MASA which log is requested so the
   appropriate log can be prepared for the response.  Using the same
   media type and message minimizes cryptographic and message operations
   although it results in additional network traffic.  The relying MASA
   implementation MAY leverage internal state to associate this request
   with the original, and by now already validated, voucher-request so
   as to avoid an extra crypto validation.

   A registrar MAY request logs at future times.  If the registrar
   generates a new request then the MASA is forced to perform the
   additional cryptographic operations to verify the new request.

   A MASA that receives a request for a device that does not exist, or
   for which the requesting owner was never an owner returns an HTTP 404
   ("Not found") code.

   Rather than returning the audit log as a response to the POST (with a
   return code 200), the MASA MAY instead return a 201 ("Created")
   response ([RFC7231] sections 6.3.2 and 7.1) containing a URL to the
   prepared (and idempotent, therefore cachable) audit response.

   In order to avoid enumeration of device audit logs, MASA that return
   URLs SHOULD take care to make the returned URL unguessable.
   [W3C.WD-capability-urls-20140218] provides very good additional
   guidance.  For instance, rather than returning URLs containing a
   database number such as https://example.com/auditlog/1234 or the EUI
   of the device such https://example.com/auditlog/10-00-00-11-22-33,
   the MASA SHOULD return a randomly generated value (a "slug" in web
   parlance).  The value is used to find the relevant database entry.

   A MASA that returns a code 200 MAY also include a Location: header
   for future reference by the registrar.

5.8.1.  MASA audit log response

   A log data file is returned consisting of all log entries associated
   with the device selected by the IDevID presented in the request.  The
   audit log may be abridged by removal of old or repeated values as
   explained below.  The returned data is in JSON format ([RFC7159]),
   and the Content-Type SHOULD be "application/json".  For example:

  {
    "version":"1",
    "events":[
      {
          "date":"<date/time of the entry>",
          "domainID":"<domainID extracted from voucher-request>",
          "nonce":"<any nonce if supplied (or NULL)>",
          "assertion":"<the value from the voucher assertion leaf>",
          "truncated":"<the number of domainID entries truncated>"
      },
      {
          "date":"<date/time of the entry>",
          "domainID":"<anotherDomainID extracted from voucher-request>",
          "nonce":"<any nonce if supplied (or NULL)>",
          "assertion":"<the value from the voucher assertion leaf>"
      }
    ],
      "truncation": {
          "nonced duplicates": "<total number of entries truncated>",
          "nonceless duplicates": "<total number of entries truncated>",
          "arbitrary": "<number of domainID entries removed entirely>"
       }
  }

                 Figure 16: Example of audit-log response

   Distribution of a large log is less than ideal.  This structure can
   be optimized as follows: Nonced or Nonceless entries for the same
   domainID MAY be abridged from the log leaving only the single most
   recent nonced or nonceless entry for that domainID.  In the case of
   truncation the 'event' truncation value SHOULD contain a count of the
   number of events for this domainID that were omitted.  The log SHOULD
   NOT be further reduced but there could exist operational situation
   where maintaining the full log is not possible.  In such situations
   the log MAY be arbitrarily abridged for length, with the number of
   removed entries indicated as 'arbitrary'.

   If the truncation count exceeds 1024 then the MASA MAY use this value
   without further incrementing it.

   A log where duplicate entries for the same domain have been omitted
   ("nonced duplicates" and/or "nonceless duplicates) could still be
   acceptable for informed decisions.  A log that has had "arbitrary"
   truncations is less acceptable but manufacturer transparency is
   better than hidden truncations.

   A registrar that sees a version value greater than 1 indicates an
   audit log format that has been enhanced with additional information.
   No information will be removed in future versions; should an
   incompatible change be desired in the future, then a new HTTP end
   point will be used.

   This document specifies a simple log format as provided by the MASA
   service to the registrar.  This format could be improved by
   distributed consensus technologies that integrate vouchers with
   technologies such as block-chain or hash trees or optimized logging
   approaches.  Doing so is out of the scope of this document but is an
   anticipated improvement for future work.  As such, the registrar
   SHOULD anticipate new kinds of responses, and SHOULD provide operator
   controls to indicate how to process unknown responses.

5.8.2.  Registrar audit log verification

   Each time the Manufacturer Authorized Signing Authority (MASA) issues
   a voucher, it appends details of the assignment to an internal audit
   log for that device.  The internal audit log is processed when
   responding to requests for details as described in Section 5.8.  The
   contents of the audit log can express a variety of trust levels, and
   this section explains what kind of trust a registrar can derive from
   the entries.

   While the audit log provides a list of vouchers that were issued by
   the MASA, the vouchers are issued in response to voucher-requests,
   and it is the contents of the voucher-requests which determines how
   meaningful the audit log entries are.

   A registrar SHOULD use the log information to make an informed
   decision regarding the continued bootstrapping of the pledge.  The
   exact policy is out of scope of this document as it depends on the
   security requirements within the registrar domain.  Equipment that is
   purchased pre-owned can be expected to have an extensive history.
   The following discussion is provided to help explain the value of
   each log element:

   date:  The date field provides the registrar an opportunity to divide
      the log around known events such as the purchase date.  Depending
      on context known to the registrar or administrator events before/
      after certain dates can have different levels of importance.  For
      example for equipment that is expected to be new, and thus have no
      history, it would be a surprise to find prior entries.

   domainID:  If the log includes an unexpected domainID then the pledge
      could have imprinted on an unexpected domain.  The registrar can
      be expected to use a variety of techniques to define "unexpected"
      ranging from white lists of prior domains to anomaly detection
      (e.g. "this device was previously bound to a different domain than
      any other device deployed").  Log entries can also be compared
      against local history logs in search of discrepancies (e.g. "this
      device was re-deployed some number of times internally but the
      external audit log shows additional re-deployments our internal
      logs are unaware of").

   nonce:  Nonceless entries mean the logged domainID could
      theoretically trigger a reset of the pledge and then take over
      management by using the existing nonceless voucher.

   assertion:  The assertion leaf in the voucher and audit log indicates
      why the MASA issued the voucher.  A "verified" entry means that
      the MASA issued the associated voucher as a result of positive
      verification of ownership but this can still be problematic for
      registrar's that expected only new (not pre-owned) pledges.  A
      "logged" assertion informs the registrar that the prior vouchers
      were issued with minimal verification.  A "proximity" assertion
      assures the registrar that the pledge was truly communicating with
      the prior domain and thus provides assurance that the prior domain
      really has deployed the pledge.

   A relatively simple policy is to white list known (internal or
   external) domainIDs.  To require all vouchers to have a nonce.
   Alternatively to require that all nonceless vouchers be from a subset
   (e.g. only internal) domainIDs.  If the policy is violated a simple
   action is to revoke any locally issued credentials for the pledge in
   question or to refuse to forward the voucher.  The Registrar MUST
   then refuse any EST actions, and SHOULD inform a human via a log.  A
   registrar MAY be configured to ignore (i.e. override the above
   policy) the history of the device but it is RECOMMENDED that this
   only be configured if hardware assisted (i.e.  TPM anchored) Network
   Endpoint Assessment (NEA) [RFC5209] is supported.

5.9.  EST Integration for PKI bootstrapping

   The pledge SHOULD follow the BRSKI operations with EST enrollment
   operations including "CA Certificates Request", "CSR Attributes" and
   "Client Certificate Request" or "Server-Side Key Generation", etc.
   This is a relatively seamless integration since BRSKI REST calls
   provide an automated alternative to the manual bootstrapping method
   described in [RFC7030].  As noted above, use of HTTP 1.1 persistent
   connections simplifies the pledge state machine.

   Although EST allows clients to obtain multiple certificates by
   sending multiple CSR requests; BRSKI does not support this mechanism
   directly.  This is because BRSKI pledges MUST use the CSR Attributes
   request ([RFC7030] section 4.5).  The registrar MUST validate the CSR
   against the expected attributes.  This implies that client requests
   will "look the same" and therefore result in a single logical
   certificate being issued even if the client were to make multiple
   requests.  Registrars MAY contain more complex logic but doing so is
   out-of-scope of this specification.  BRSKI does not signal any
   enhancement or restriction to this capability.

5.9.1.  EST Distribution of CA Certificates

   The pledge SHOULD request the full EST Distribution of CA
   Certificates message.  See RFC7030, section 4.1.

   This ensures that the pledge has the complete set of current CA
   certificates beyond the pinned-domain-cert (see Section 5.6.2 for a
   discussion of the limitations inherent in having a single certificate
   instead of a full CA Certificates response.)  Although these
   limitations are acceptable during initial bootstrapping, they are not
   appropriate for ongoing PKIX end entity certificate validation.

5.9.2.  EST CSR Attributes

   Automated bootstrapping occurs without local administrative
   configuration of the pledge.  In some deployments it is plausible
   that the pledge generates a certificate request containing only
   identity information known to the pledge (essentially the X.509
   IDevID information) and ultimately receives a certificate containing
   domain specific identity information.  Conceptually the CA has
   complete control over all fields issued in the end entity
   certificate.  Realistically this is operationally difficult with the
   current status of PKI certificate authority deployments, where the
   CSR is submitted to the CA via a number of non-standard protocols.
   Even with all standardized protocols used, it could operationally be
   problematic to expect that service specific certificate fields can be
   created by a CA that is likely operated by a group that has no
   insight into different network services/protocols used.  For example,
   the CA could even be outsourced.

   To alleviate these operational difficulties, the pledge MUST request
   the EST "CSR Attributes" from the EST server and the EST server needs
   to be able to reply with the attributes necessary for use of the
   certificate in its intended protocols/services.  This approach allows
   for minimal CA integrations and instead the local infrastructure (EST
   server) informs the pledge of the proper fields to include in the
   generated CSR.  This approach is beneficial to automated
   bootstrapping in the widest number of environments.

   If the hardwareModuleName in the X.509 IDevID is populated then it
   SHOULD by default be propagated to the LDevID along with the
   hwSerialNum.  The EST server SHOULD support local policy concerning
   this functionality.

   In networks using the BRSKI enrolled certificate to authenticate the
   ACP (Autonomic Control Plane), the EST CSR attributes MUST include
   the ACP Domain Information Fields defined in
   [I-D.ietf-anima-autonomic-control-plane] section 6.1.2.

   The registrar MUST also confirm that the resulting CSR is formatted
   as indicated before forwarding the request to a CA.  If the registrar
   is communicating with the CA using a protocol such as full CMC, which
   provides mechanisms to override the CSR attributes, then these
   mechanisms MAY be used even if the client ignores CSR Attribute
   guidance.

5.9.3.  EST Client Certificate Request

   The pledge MUST request a new client certificate.  See RFC7030,
   section 4.2.

5.9.4.  Enrollment Status Telemetry

   For automated bootstrapping of devices, the administrative elements
   providing bootstrapping also provide indications to the system
   administrators concerning device lifecycle status.  This might
   include information concerning attempted bootstrapping messages seen
   by the client.  The MASA provides logs and status of credential
   enrollment.  [RFC7030] assumes an end user and therefore does not
   include a final success indication back to the server.  This is
   insufficient for automated use cases.

   In order to communicate this indicator, the client HTTP POSTs the
   following to the server at the new EST endpoint at "/.well-known/est/
   enrollstatus".

   To indicate successful enrollment the client SHOULD first re-
   negotiate the EST TLS session using the newly obtained credentials.
   TLS 1.2 supports doing this in-band, but TLS 1.3 does not.  The
   client SHOULD therefore close the existing TLS connection, and start
   a new one.

   In the case of a FAIL, the Reason string indicates why the most
   recent enrollment failed.  The SubjectKeyIdentifier field MUST be
   included if the enrollment attempt was for a keypair that is locally
   known to the client.  If EST /serverkeygen was used and failed then
   the field is omitted from the status telemetry.

   In the case of a SUCCESS the Reason string is omitted.  The
   SubjectKeyIdentifier is included so that the server can record the
   successful certificate distribution.

   An example status report can be seen below.  It is sent with with the
   media type: application/json

   {
     "version":"1",
     "Status":true,
     "Reason":"Informative human readable message",
     "reason-context": "Additional information"
   }

               Figure 17: Example of enrollment status POST

   The server SHOULD respond with an HTTP 200 but MAY simply fail with
   an HTTP 404 error.

   Within the server logs the server MUST capture if this message was
   received over an TLS session with a matching client certificate.

5.9.5.  Multiple certificates

   Pledges that require multiple certificates could establish direct EST
   connections to the registrar.

5.9.6.  EST over CoAP

   This document describes extensions to EST for the purposes of
   bootstrapping of remote key infrastructures.  Bootstrapping is
   relevant for CoAP enrollment discussions as well.  The definition of
   EST and BRSKI over CoAP is not discussed within this document beyond
   ensuring proxy support for CoAP operations.  Instead it is
   anticipated that a definition of CoAP mappings will occur in
   subsequent documents such as [I-D.ietf-ace-coap-est] and that CoAP
   mappings for BRSKI will be discussed either there or in future work.

6.  Clarification of transfer-encoding

   [RFC7030] defines it's endpoints to include a "Content-Transfer-
   Encoding" heading, and the payloads to be [RFC4648] Base64 encoded
   DER.

   When used within BRSKI, the original RFC7030 EST endpoints remain
   Base64 encoded, but the new BRSKI end points which send and receive
   binary artifacts (specifically, /requestvoucher) are binary.  That
   is, no encoding is used.

   In the BRSKI context, the EST "Content-Transfer-Encoding" header
   field if present, SHOULD be ignored.  This header field does not need
   to be included.

7.  Reduced security operational modes

   A common requirement of bootstrapping is to support less secure
   operational modes for support specific use cases.  The following
   sections detail specific ways that the pledge, registrar and MASA can
   be configured to run in a less secure mode for the indicated reasons.

   This section is considered non-normative in the generality of the
   protocol.  Use of the suggested mechanism here MUST be detailed in
   specific profiles of BRSKI, such as in Section 9.

7.1.  Trust Model

   This section explains the trust relationships detailed in
   Section 2.4:

   +--------+         +---------+    +------------+     +------------+
   | Pledge |         | Join    |    | Domain     |     |Manufacturer|
   |        |         | Proxy   |    | Registrar  |     | Service    |
   |        |         |         |    |            |     | (Internet) |
   +--------+         +---------+    +------------+     +------------+

   Figure 10

   Pledge:  The pledge could be compromised and providing an attack
      vector for malware.  The entity is trusted to only imprint using
      secure methods described in this document.  Additional endpoint
      assessment techniques are RECOMMENDED but are out-of-scope of this
      document.

   Join Proxy:  Provides proxy functionalities but is not involved in
      security considerations.

   Registrar:  When interacting with a MASA a registrar makes all
      decisions.  For Ownership Audit Vouchers (see [RFC8366]) the
      registrar is provided an opportunity to accept MASA decisions.

   Vendor Service, MASA:  This form of manufacturer service is trusted
      to accurately log all claim attempts and to provide authoritative
      log information to registrars.  The MASA does not know which
      devices are associated with which domains.  These claims could be
      strengthened by using cryptographic log techniques to provide
      append only, cryptographic assured, publicly auditable logs.

   Vendor Service, Ownership Validation:  This form of a SUCCESS the Reason string manufacturer
      service is omitted.  The
   SubjectKeyIdentifier trusted to accurately know which device is included so that the server can record the
   successful certificate distribution.

   Status media type: application/json owned by
      which domain.

7.2.  Pledge security reductions

   The client HTTP POSTs the following pledge can choose to the server at the new EST well
   known URI /enrollstatus.

   {
     "version":"1",
     "Status":true,
     "Reason":"Informative human readable message",
     "reason-context": "Additional information"
   }

                Figure 4: Example of enrollment status POST accept vouchers using less secure methods.
   These methods enable offline and emergency (touch based) deployment
   use cases:

   1.  The server SHOULD respond with an HTTP 200 but MAY simply fail with
   an HTTP 404 error.

   Within the server logs the server pledge MUST capture if this message was
   received over an TLS session with a matching client certificate. accept nonceless vouchers.  This allows for clients that wish to minimize their crypto operations
   to simply POST this response without renegotiating the TLS session -
   at the cost of a use
       case where the server registrar can not being able to accurately verify that
   enrollment was truly successful.

5.9.5.  Multiple certificates

   Pledges that require multiple certificates could establish direct EST
   connections connect to the registrar.

5.9.6.  EST over CoAP

   This document describes extensions to EST for MASA at the purposes of
   bootstrapping
       deployment time.  Logging and validity periods address the
       security considerations of remote key infrastructures.  Bootstrapping is
   relevant supporting these use cases.

   2.  Many devices already support "trust on first use" for CoAP enrollment discussions physical
       interfaces such as well.  The definition of
   EST and BRSKI over CoAP is console ports.  This document does not discussed within change
       that reality.  Devices supporting this document beyond
   ensuring proxy protocol MUST NOT support for CoAP operations.  Instead it
       "trust on first use" on network interfaces.  This is
   anticipated that because
       "trust on first use" over network interfaces would undermine the
       logging based security protections provided by this
       specification.

   3.  The pledge MAY have an operational mode where it skips voucher
       validation one time.  For example if a definition of CoAP mappings will occur in
   subsequent documents such as [I-D.ietf-ace-coap-est] and that CoAP
   mappings for BRSKI will physical button is
       depressed during the bootstrapping operation.  This can be discussed either there useful
       if the manufacturer service is unavailable.  This behavior SHOULD
       be available via local configuration or in future work.

6.  Clarification physical presence methods
       (such as use of transfer-encoding

   [RFC7030] defines it's endpoints to include a "Content-Transfer-
   Encoding" heading, and the payloads serial/craft console) to ensure new entities
       can always be [RFC4648] Base64 encoded
   DER.

   When used within BRSKI, deployed even when autonomic methods fail.  This
       allows for unsecured imprint.

   4.  A craft/serial console could include a command such as "est-
       enroll [2001:db8:0:1]:443" that begins the original RFC7030 EST endpoints remain
   Base64 encoded, but the new BRSKI end points which send and receive
   binary artifacts (specifically, /requestvoucher) are binary.  That
   is, no encoding is used.

   In process from the BRSKI context,
       point after the EST "Content-Transfer-Encoding" header
   field if present, voucher is validated.  This process SHOULD
       include server certificate verification using an on-screen
       fingerprint.

   It is RECOMMENDED that "trust on first use" or any method of skipping
   voucher validation (including use of craft serial console) only be ignored.
   available if hardware assisted Network Endpoint Assessment [RFC5209]
   is supported.  This header field does not need
   to included.

7.  Reduced security operational modes

   A common requirement recommendation ensures that domain network
   monitoring can detect inappropriate use of offline or emergency
   deployment procedures when voucher-based bootstrapping is not used.

7.3.  Registrar security reductions

   A registrar can choose to support accept devices using less secure
   operational modes for support specific use cases.  The following
   sections detail specific ways that methods.
   These methods are acceptable when low security models are needed, as
   the pledge, registrar and MASA can security decisions are being made by the local administrator, but
   they MUST NOT be configured the default behavior:

   1.  A registrar MAY choose to run in accept all devices, or all devices of a less secure mode for
       particular type, at the indicated reasons. administrator's discretion.  This section is considered non-normative in the generality could
       occur when informing all registrars of the
   protocol.  Use unique identifiers of the suggested mechanism here MUST new
       entities might be detailed in
   specific profiles operationally difficult.

   2.  A registrar MAY choose to accept devices that claim a unique
       identity without the benefit of BRSKI, such as in Section 9.

7.1.  Trust Model authenticating that claimed
       identity.  This section explains could occur when the trust relationships detailed in
   Section 2.4:

   +--------+         +---------+    +------------+     +------------+
   | Pledge |         | Join    |    | Domain     |     |Manufacturer|
   |        |         | Proxy   |    | Registrar  |     | Service    |
   |        |         |         |    |            |     | (Internet) |
   +--------+         +---------+    +------------+     +------------+

   Figure 10

   Pledge:  The pledge could be compromised and providing does not include an
       X.509 IDevID factory installed credential.  New Entities without
       an attack
      vector for malware.  The entity X.509 IDevID credential MAY form the Section 5.2 request using
       the Section 5.5 format to ensure the pledge's serial number
       information is trusted provided to only imprint using
      secure methods described in this document.  Additional endpoint
      assessment techniques are RECOMMENDED but are out-of-scope of this
      document.

   Join Proxy:  Provides proxy functionalities but the registrar (this includes the
       IDevID AuthorityKeyIdentifier value, which would be statically
       configured on the pledge.)  The pledge MAY refuse to provide a
       TLS client certificate (as one is not involved available.)  The pledge
       SHOULD support HTTP-based or certificate-less TLS authentication
       as described in
      security considerations.

   Registrar:  When interacting EST RFC7030 section 3.3.2.  A registrar MUST NOT
       accept unauthenticated New Entities unless it has been configured
       to do so by an administrator that has verified that only expected
       new entities can communicate with a MASA a registrar makes all
      decisions.  For Ownership Audit Vouchers (see [RFC8366]) the (presumably via a
       physically secured perimeter.)

   3.  A registrar is provided an opportunity MAY submit a nonceless voucher-requests to accept the MASA decisions.

   Vendor Service, MASA:  This form of manufacturer
       service is trusted
      to accurately log all claim attempts and to provide authoritative
      log information to registrars.  The MASA does (by not know which
      devices are associated with which domains.  These claims could including a nonce in the voucher-request.)  The
       resulting vouchers can then be
      strengthened stored by using cryptographic log techniques to provide
      append only, cryptographic assured, publicly auditable logs.
      Current text provides only for a trusted manufacturer.

   Vendor Service, Ownership Validation: the registrar until they
       are needed during bootstrapping operations.  This form of manufacturer
      service is trusted to accurately know which device for use
       cases where the target network is owned protected by
      which domain.

7.2.  Pledge security reductions

   The pledge can choose to accept vouchers using less secure methods.
   These methods enable offline an air gap and emergency (touch based) deployment
   use cases:

   1.  The
       therefore cannot contact the MASA service during pledge MUST accept
       deployment.

   4.  A registrar MAY ignore unrecognized nonceless vouchers. log entries.  This allows for
       could occur when used equipment is purchased with a use
       case where the valid history
       being deployed in air gap networks that required permanent
       vouchers.

   5.  A registrar MAY accept voucher formats of future types that can
       not connect to be parsed by the MASA at Registrar.  This reduces the
       deployment time.  Logging and validity periods address Registrar's
       visibility into the
       security considerations of supporting these use cases.

   2.  Many devices already support "trust on first use" for physical
       interfaces such as console ports.  This document exact voucher contents but does not change
       that reality.  Devices supporting this protocol MUST NOT support
       "trust on first use" on network interfaces.  This is because
       "trust on first use" over network interfaces would undermine
       the
       logging based protocol operations.

7.4.  MASA security protections provided reductions

   Lower security modes chosen by this
       specification.

   3.  The pledge MAY have an operational mode where it skips voucher
       validation one time.  For example if a physical button is
       depressed during the bootstrapping operation.  This MASA service affect all device
   deployments unless the lower-security behavior is tied to specific
   device identities.  The modes described below can be applied to
   specific devices via knowledge of what devices were sold.  They can
   also be useful
       if bound to specific customers (independent of the manufacturer service is unavailable.  This behavior SHOULD
       be available via local configuration or physical presence methods
       (such as use device
   identity) by authenticating the customer's Registrar.

7.4.1.  Issuing Nonceless vouchers

   A MASA has the option of not including a serial/craft console) nonce is in the voucher,
   and/or not requiring one to ensure new entities
       can always be deployed even when autonomic methods fail. present in the voucher-request.  This
       allows for unsecured imprint.

   4.  A craft/serial console COULD include
   results in distribution of a command such as "est-
       enroll [2001:db8:0:1]:443" voucher that begins the EST process from the
       point after never expires and in effect
   makes the voucher is validated.  This process SHOULD
       include server certificate verification using Domain an on-screen
       fingerprint.

   It is RECOMMENDED that "trust on first use" or always trusted entity to the pledge during any method of skipping
   subsequent bootstrapping attempts.  That a nonceless voucher validation (including use of craft serial console) only be
   available if hardware assisted Network Endpoint Assessment [RFC5209] was
   issued is supported.  This recommendation ensures captured in the log information so that domain network
   monitoring can detect inappropriate use of offline or emergency
   deployment procedures when voucher-based bootstrapping is not used.

7.3.  Registrar security reductions

   A the registrar can choose to accept devices using less secure methods.
   These methods are acceptable when low security models are needed, as
   the
   make appropriate security decisions are being made by when a pledge joins the local administrator, but
   they MUST NOT Domain.
   This is useful to support use cases where registrars might not be
   online during actual device deployment.

   While a nonceless voucher may include an expiry date, a typical use
   for a nonceless voucher is for it to be long-lived.  If the default behavior:

   1.  A registrar MAY choose device
   can be trusted to accept all devices, or all devices of have an accurate clock (the MASA will know), then a
       particular type, at the administrator's discretion.  This could
       occur when informing all registrars of unique identifiers of new
       entities might
   nonceless voucher CAN be operationally difficult.

   2. issued with a limited lifetime.

   A registrar MAY choose more typical case for a nonceless voucher is for use with offline
   onboarding scenarios where it is not possible to accept devices that claim pass a unique
       identity without fresh
   voucher-request to the benefit MASA.  The use of authenticating that claimed
       identity.  This could occur when a long-lived voucher also
   eliminates concern about the pledge availability of the MASA many years in
   the future.  Thus many nonceless vouchers will have no expiry dates.

   Thus, the long lived nonceless voucher does not include an
       X.509 IDevID factory installed credential.  New Entities without
       an X.509 IDevID credential MAY form the Section 5.2 request using require the Section 5.5 format to ensure proof
   that the pledge's serial number
       information device is provided to online.  Issuing such a thing is only accepted
   when the registrar (this includes is authenticated by the
       IDevID AuthorityKeyIdentifier value, which would be statically
       configured on MASA and the pledge.)  The pledge MAY refuse MASA is
   authorized to provide a
       TLS client certificate (as one is not available.)  The pledge
       SHOULD support HTTP-based or certificate-less TLS authentication
       as described in EST RFC7030 section 3.3.2.  A registrar MUST NOT
       accept unauthenticated New Entities unless it has been configured this functionality to do so by an administrator that has verified that this customer.  The MASA
   is RECOMMENDED to use this functionality only expected
       new entities can communicate in concert with an
   enhanced level of ownership tracking (out-of-scope.)

   If the pledge device is known to have a registrar (presumably via real-time-clock that is set
   from the factory, use of a
       physically secured perimeter.)

   3. voucher validity period is RECOMMENDED.

7.4.2.  Trusting Owners on First Use

   A registrar MAY submit a nonceless voucher-requests to the MASA
       service (by has the option of not including verifying ownership before responding
   with a nonce in the voucher-request.)  The
       resulting vouchers can then be stored by the registrar until they
       are needed during bootstrapping operations. voucher.  This is for use
       cases where the target network is protected by an air gap and
       therefore cannot contact expected to be a common operational model
   because doing so relieves the manufacturer providing MASA service services
   from having to track ownership during pledge
       deployment.

   4. shipping and supply chain and
   allows for a very low overhead MASA service.  A registrar MAY ignore unrecognized nonceless uses the
   audit log entries.  This
       could occur when used equipment is purchased with information as a valid history
       being deployed defense in air gap networks that required permanent
       vouchers.

   5.  A registrar MAY accept voucher formats of future types depth strategy to ensure that can
       not be parsed by the Registrar.  This reduces the Registrar's
       visibility into the exact voucher contents but
   this does not change occur unexpectedly (for example when purchasing new
   equipment the protocol operations.

7.4. registrar would throw an error if any audit log
   information is reported.)  The MASA security reductions

   Lower security modes chosen by SHOULD verify the 'prior-signed-
   voucher-request' information for pledges that support that
   functionality.  This provides a proof-of-proximity check that reduces
   the need for ownership verification.

   A MASA service affect all device
   deployments unless bound that practices Trust-on-First-Use (TOFU) for Registrar
   identity may wish to annotate the specific device identities.  In which
   case these modes can be provided as additional features for specific
   customers.  The origin of the connection by IP
   address or netblock, and restrict future use of that identity from
   other locations.  A MASA service can choose that does this SHOULD take care to run in less secure modes
   by:

   1.  Not enforcing not
   create nuissance situations for itself when a customer has multiple
   registrars, or uses outgoing IPv6 NAT44 connections that change
   frequently.

8.  IANA Considerations

   This document requires the following IANA actions:

8.1.  The IETF XML Registry

   This document registers a nonce is URI in the voucher. "IETF XML Registry" [RFC3688].
   IANA has registered the following:

      URI: urn:ietf:params:xml:ns:yang:ietf-mud-brski-masa
      Registrant Contact: The ANIMA WG of the IETF.
      XML: N/A, the requested URI is an XML namespace.

8.2.  Well-known EST registration

   This results in
       distribution document extends the definitions of a voucher that never expires and "est" (so far defined via
   RFC7030) in effect makes the Domain an always trusted entity "https://www.iana.org/assignments/well-known-uris/
   well-known-uris.xhtml" registry.  IANA is asked to change the pledge during any
       subsequent bootstrapping attempts.  That
   registration of "est" to include RFC7030 and this occurred document.

8.3.  PKIX Registry

   IANA is
       captured in the log information so that the registrar can make
       appropriate security decisions when a pledge joins requested to register the Domain. following:

   This is useful to support use cases where registrars might not be
       online during actual device deployment.  Because this results in document requests a long lived voucher and does not require the proof that number for id-mod-MASAURLExtn2016(TBD) from
   the
       device is online, this is only accepted when pkix(7) id-mod(0) Registry.

   This document has received an early allocation from the registrar is
       authenticated by id-pe
   registry (SMI Security for PKIX Certificate Extension) for id-pe-
   masa-url with the MASA and authorized to provide this
       functionality.  The MASA is RECOMMENDED to use this functionality
       only value 32, resulting in concert with an enhanced level OID of ownership tracking
       (out-of-scope.)  If the pledge device
   1.3.6.1.5.5.7.1.32.

8.4.  Pledge BRSKI Status Telemetry

   IANA is known requested to have create a real-
       time-clock new Registry entitled: "BRSKI
   Parameters", and within that is set from the factory, use of a voucher
       validity period is RECOMMENDED.

   2.  Not verifying ownership before responding with a voucher.  This
       is expected Registry to be create a common operational model because doing so
       relieves table called:
   "Pledge BRSKI Status Telemetry Attributes".  New items can be added
   using the manufacturer providing MASA services from having Specification Required.  The following items are to
       track ownership during shipping and supply chain and allows for a
       very low overhead MASA service.  A registrar uses the audit log
       information as a defense be in depth strategy to ensure that
   the initial registration, with this
       does not occur unexpectedly (for example when purchasing new
       equipment document (Section 5.7) as the registrar would throw an error if any audit log
       information
   reference:

   o  version

   o  Status

   o  Reason

   o  reason-context

8.5.  DNS Service Names

   IANA is reported.)  The MASA SHOULD verify requested to register the 'prior-
       signed-voucher-request' information following Service Names:

   Service Name: brski-proxy
   Transport Protocol(s): tcp
   Assignee: IESG <iesg@ietf.org>.
   Contact: IESG <iesg@ietf.org>
   Description: The Bootstrapping Remote Secure Key
                Infrastructures Proxy
   Reference: [This document]

   Service Name: brski-registrar
   Transport Protocol(s): tcp
   Assignee: IESG <iesg@ietf.org>.
   Contact: IESG <iesg@ietf.org>
   Description: The Bootstrapping Remote Secure Key
                Infrastructures Registrar
   Reference: [This document]

8.6.  MUD File Extension for pledges that support that
       functionality.  This provides a proof-of-proximity check that
       reduces the need for ownership verification.

8. MASA

   The IANA Considerations

   This document requires is requested to list the following IANA actions:

8.1.  Well-known EST registration

   This document extends name "masa" in the definitions of "est" (so far MUD extensions
   registry defined via
   RFC7030) in the "https://www.iana.org/assignments/well-known-uris/
   well-known-uris.xhtml" registry.  IANA is asked to change the
   registration of "est" to include RFC7030 and this document.

8.2.  PKIX Registry

   IANA [RFC8520].  Its use is requested documented in Appendix C.

9.  Applicability to register the following: Autonomic Control Plane

   This document requests provides a number solution to the requirements for id-mod-MASAURLExtn2016(TBD) from secure
   bootstrap set out in Using an Autonomic Control Plane for Stable
   Connectivity of Network Operations, Administration, and Maintenance
   [RFC8368], A Reference Model for Autonomic Networking
   [I-D.ietf-anima-reference-model] and specifically the pkix(7) id-mod(0) Registry.

   This An Autonomic
   Control Plane (ACP) [I-D.ietf-anima-autonomic-control-plane], section
   3.2 (Secure Bootstrap), and section 6.1 (ACP Domain, Certificate and
   Network).

   The protocol described in this document has received an early allocation from appeal in a number of
   other non-ANIMA use cases.  Such uses of the id-pe
   registry (SMI Security for PKIX Certificate Extension) for id-pe-
   masa-url protocol will be
   deploying into other environments with different tradeoffs of
   privacy, security, reliability and autonomy from manufacturers.  As
   such those use cases will need to provide their own applicability
   statements, and will need to address unique privacy and security
   considerations for the environments in which they are used.

   The autonomic control plane (ACP) that is bootstrapped by the BRSKI
   protocol is typically used by medium to large Internet Service
   Provider organizations.  Equivalent enterprises that has significant
   layer-3 router connectivity also will find significant benefit,
   particularly if the value 32, resulting in an OID Enterprise has many sites.  (A network consisting
   of
   1.3.6.1.5.5.7.1.32.

8.3.  Pledge BRSKI Status Telemetry

   IANA primarily layer-2 is requested to create a new Registry entitled: "BRSKI
   Parameters", and within not excluded, but the adjacencies that Registry to the
   ACP will create a table called:
   "Pledge BRSKI Status Telemetry Attributes".  New items can be added
   using and maintain will not reflect the Specification Required.  The following items are to be topology until all
   devices participate in the initial registration, with this document (Section 5.7) as ACP).

   As specified in the
   reference:

   o  version

   o  Status

   o  Reason

   o  reason-context

8.4.  DNS Service Names

   IANA is requested to register ANIMA charter, this work "..focuses on
   professionally-managed networks."  Such a network has an operator and
   can do things like install, configure and operate the following Service Names:

   Service Name: brski-proxy
   Transport Protocol(s): tcp
   Assignee: IESG <iesg@ietf.org>.
   Contact: IESG <iesg@ietf.org>
   Description: The Bootstrapping Remote Secure Key
                Infrastructures Proxy
   Reference: [This document]

   Service Name: brski-registrar
   Transport Protocol(s): tcp
   Assignee: IESG <iesg@ietf.org>.
   Contact: IESG <iesg@ietf.org>
   Description: The Bootstrapping Remote Secure Key
                Infrastructures Registrar
   Reference: [This document]

8.5.  MUD File Extension for the MASA
   function.  The IANA operator makes purchasing decisions and is requested aware of
   what manufacturers it expects to list see on its network.

   Such an operator is also capable of performing bootstrapping of a
   device using a serial-console (craft console).  The zero-touch
   mechanism presented in this and the name "masa" ACP document
   [I-D.ietf-anima-autonomic-control-plane] represents a significiant
   efficiency: in particular it reduces the MUD extensions
   registry defined need to put senior experts
   on airplanes to configure devices in [I-D.ietf-opsawg-mud].  Its use person.

   There is documented in
   Appendix C.

9.  Applicability to a recognition as the Autonomic Control Plane

   This document provides technology evolves that not every
   situation may work out, and occasionally a solution human may still have to the requirements for secure
   bootstrap set out
   visit.  In recognition of this, some mechanisms are presented in Using an Autonomic Control Plane for Stable
   Connectivity
   Section 7.2.  The manufacturer MUST provide at least one of Network Operations, Administration, and Maintenance
   [RFC8368], A Reference Model for Autonomic Networking
   [I-D.ietf-anima-reference-model] and specifically the An Autonomic
   Control Plane (ACP) [I-D.ietf-anima-autonomic-control-plane], section
   3.2 (Secure Bootstrap), and section 6.1 (ACP Domain, Certificate and
   Network).

   The protocol one-
   touch mechanisms described in this document has appeal in a number of
   other non-ANIMA use cases.  Such uses that permit enrollment to be proceed
   without availability of any manufacturer server (such as the MASA).

   The BRSKI protocol will be
   deploying is going into other environments with different tradeoffs where there have
   already been quite a number of
   privacy, security, reliability and autonomy from manufacturers.  As
   such those use cases will need vendor proprietary management systems.
   Those are not expected to provide their own applicability
   statements, and will need go away quickly, but rather to address unique privacy leverage the
   secure credentials that are provisioned by BRSKI.  The connectivity
   requirements of said management systems are provided by the ACP.

10.  Privacy Considerations

10.1.  MASA audit log

   The MASA audit log includes a hash of the domainID for each Registrar
   a voucher has been issued to.  This information is closely related to
   the actual domain identity.  A MASA may need additional defenses
   against Denial of Service attacks (Section 11.1), and security
   considerations this may
   involve collecting additional (unspecified here) information.  This
   could provide sufficient information for the environments in which they are used.

   The autonomic control plane MASA service to build a
   detailed understanding the devices that this document provides bootstrap for
   is typically have been provisioned within
   a medium to large Internet Service Provider
   organization, or an equivalent Enterprise domain.

   There are a number of design choices that mitigate this risk.  The
   domain can maintain some privacy since it has significant
   layer-3 router connectivity.  (A network consisting of primarily
   layer-2 not necessarily been
   authenticated and is not excluded, but authoritatively bound to the adjacencies that supply chain.

   Additionally the ACP will create
   and maintain will not reflect domainID captures only the topology until all devices
   participate in unauthenticated subject
   key identifier of the ACP).

   As specified domain.  A privacy sensitive domain could
   theoretically generate a new domainID for each device being deployed.
   Similarly a privacy sensitive domain would likely purchase devices
   that support proximity assertions from a manufacturer that does not
   require sales channel integrations.  This would result in the ANIMA charter, this work "..focuses on
   professionally-managed networks."  Such a network has an operator and
   can do things like install, configure and operate
   significant level of privacy while maintaining the security
   characteristics provided by Registrar
   function. based audit log inspection.

10.2.  What BRSKI-MASA reveals to the manufacturer

   The operator makes purchasing decisions so-called "call-home" mechanism that occurs as part of the BRSKI-
   MASA connection standardizes what has been deemed by some as a
   sinister mechanism for corporate oversight of individuals.
   ([livingwithIoT] and is aware [IoTstrangeThings] for a small sample).

   As the Autonomic Control Plane (ACP) usage of
   what manufacturers it expects to see on it's network.

   Such an operator BRSKI is also capable not targeted
   at individual usage of performing bootstrapping IoT devices, but rather at the Enterprise and
   ISP creation of networks in a
   device using a serial-console (craft console).  The zero-touch
   mechanism presented in this and fashion, the ACP document "call-home"
   represents a
   significiant efficiency: in particular it reduces the need to put
   senior experts on airplanes different kind of concern.

   It needs to configure devices in person.

   There be re-iterated that the BRSKI-MASA mechanism only occurs
   once during the commissioning of the device.  It is a recognition well defined, and
   although encrypted with TLS, it could in theory be made auditable as
   the technology evolves that not every
   situation may work out, and occasionally a human may still have to
   visit.  In recognition of this, some mechanisms contents are presented in
   Section 7.2.  The manufacturer MUST provide at least one of well defined.  This connection does not occur when
   the one-
   touch mechanisms described device powers on or is restarted for normal routines.  It is
   conceivable that permit enrollment a device could be forced to go through a full
   factory reset during an exceptional firmware update situation, after
   which enrollment would have be proceed
   without availability of any manufacturer server (such as the MASA). repeated.

   The BRSKI protocol call-home mechanism is going into environments mediated via the owner's Registrar,
   and the information that is transmitted is directly auditable by the
   device owner.  This is in stark contrast to many "call-home"
   protocols where there have
   already been quite a number the device autonomously calls home and uses an
   undocumented protocol.

   While the contents of vendor proprietary management systems.
   Those the signed part of the pledge voucher request
   can not be changed, they are not expected to go away quickly, but rather encrypted at the registrar.  The
   ability to leverage audit the
   secure credentials that are provisioned messages by BRSKI.  The connectivity
   requirements the owner of said management systems are provided by the ACP.

10.  Privacy Considerations

10.1.  MASA audit log

   The MASA audit log includes network a hash mechanism
   to defend against exfiltration of the domainID for each Registrar data by a voucher has been issued to.  This nefarious pledge.  Both
   are, to re-iterate, encrypted by TLS while in transit.

   The BRSKI-MASA exchange reveals the following information is closely related to the actual
   manufacturer:

   o  the identity of the device being enrolled (down to the serial-
      number!).

   o  an identity of the domain identity, especially when paired with owner in the anti-DDoS
   authentication information form of the MASA might collect.  This domain trust
      anchor.  However, this is not a global PKI anchored name within
      the WebPKI, so this identity could
   provide sufficient information for be pseudonymous.  If there is
      sales channel integration, then the MASA service to build will have authenticated
      the domain owner, either via pinned certificate, or perhaps
      another HTTP authentication method, as per Section 5.5.3.

   o  the time the device is activated,

   o  the IP address of the domain Owner's Registrar.  For ISPs and
      Enterprises, the IP address provides very clear geolocation of the
      owner.  No amount of IP address privacy extensions ([RFC4941]) can
      do anything about this, as a
   detailed understanding simple whois lookup likely identifies
      the ISP or Enterprise from the upper bits anyway.  A passive
      attacker who observes the devices connection definitely may conclude that have been provisioned within
   a domain.

   There are
      the given enterprise/ISP is a number customer of design choices the particular equipment
      vendor.  The precise model that mitigate this risk. is being enrolled will remain
      private.

   The
   domain can maintain some privacy since it has not necessarily been
   authenticated and above situation is not authoritatively bound to the supply chain.

   Additionally the domainID captures only the unauthenticated subject
   key identifier of the domain.  A privacy sensitive domain could
   theoretically generate be distinguished from a new domainID for each device being deployed.
   Similarly residential/
   individual person who registers a privacy sensitive domain would likely purchase devices
   that support proximity assertions device from a manufacturer manufacturer: that does an
   enterprise/ISP purchases routing products is hardly worth mentioning.
   Deviations would, however, be notable.

   The situation is not
   require sales channel integrations.  This would result in a
   significant level of privacy while maintaining the security
   characteristics provided improved by Registrar based audit log inspection.

10.2.  What BRSKI-MASA reveals to the manufacturer

   The so-called "call-home" mechanism that occurs enterprise/ISP using
   anonymization services such as part of the BRSKI-
   MASA ToR [Dingledine2004], as a TLS 1.2
   connection standardizes what has been deemed will reveal the ClientCertificate used, clearly
   identifying the enterprise/ISP involved.  TLS 1.3 is better in this
   regard, but an active attacker can still discover the parties
   involved by some as performing a
   sinister mechanism for corporate oversight of individuals.
   ([livingwithIoT] and [IoTstrangeThings] for Man-In-The-Middle-Attack on the first
   attempt (breaking/killing it with a small sample).

   As TCP RST), and then letting
   subsequent connection pass through.

   A manufacturer could attempt to mix the Autonomic Control Plane (ACP) usage BRSKI-MASA traffic in with
   general traffic their site by hosting the MASA behind the same (set)
   of BRSKI load balancers that the companies normal marketing site is not targeted
   at individual usage hosted
   behind.  This makes lots of IoT devices, but rather at sense from a straight capacity planning
   point of view as the Enterprise and
   ISP creation same set of networks in a zero-touch fashion, services (and the "call-home"
   represents a different kind same set of concern.

   It needs to
   Distributed Denial of Service mitigations) may be re-iterated that used.
   Unfortunately, as the BRSKI-MASA mechanism only occurs
   once during the commissioning of the device.  It is well defined, connections include TLS
   ClientCertificate exchanges, this may easily be observed in TLS 1.2,
   and
   although encrypted with TLS, a traffic analysis may reveal it could even in theory be made auditable as
   the contents are well defined. TLS 1.3.  This connection does not occur when
   the device powers on or is restarted for normal routines.  It is
   conceivable that
   make such a device could plan irrelevant.  There may be forced other organizational
   reasons to go through a full
   factory reset during an exceptional firmware update situation, after
   which enrollment would have be repeated.

   The BRSKI call-home mechanism keep the marketing site (which is mediated via often subject to
   frequent re-designs, outsourcing, etc.) separate from the owner's Registrar, MASA, which
   may need to operate reliably for decades.

10.3.  Manufacturers and Used or Stolen Equipment

   As explained above, the manufacturer receives information each time
   that a device which is in factory-default mode does a zero-touch
   bootstrap, and attempts to enroll into a domain owner's registrar.

   The manufacturer is transmitted therefore in a position to decline to issue a
   voucher if it detects that the new owner is directly auditable by not the
   device same as the
   previous owner.

   1.  This can be seen as a feature if the equipment is in stark contrast believed to many "call-home"
   protocols where
       have been stolen.  If the legitimate owner notifies the
       manufacturer of the theft, then when the new owner brings the
       device autonomously calls home up, if they use the zero-touch mechanism, the new
       (illegitimate) owner reveals their location and uses an
   undocumented protocol.

   While identity.

   2.  In the contents case of Used equipment, the signed part initial owner could inform the
       manufacturer of the pledge voucher request
   can sale, or the manufacturer may just permit
       resales unless told otherwise.  In which case, the transfer of
       ownership simply occurs.

   3.  A manufacturer could however decide not be changed, they are to issue a new voucher in
       response to a transfer of ownership.  This is essentially the
       same as the stolen case, with the manufacturer having decided
       that the sale was not encrypted at legitimate.

   4.  There is a fourth case, if the registrar. manufacturer is providing
       protection against stolen devices.  The
   ability manufacturer then has a
       responsibility to audit the messages by protect the legitimate owner of against fraudulent
       claims that the network prevents
   exfiltration of data by equipment was stolen.  Such a nefarious pledge.  The contents of an
   unsigned voucher request are, however, completely changeable by claim would cause
       the
   Registrar.  Both are, manufacturer to re-iterate, encrypted by TLS while in
   transit.

   The BRSKI-MASA exchange reveals the following information refuse to issue a new voucher.  Should the
   manufacturer:

   o  the identity
       device go through a deep factory reset (for instance, replacement
       of a damaged main board component, the device being enrolled (down would not
       bootstrap.

   5.  Finally, there is a fifth case: the manufacturer has decided to
       end-of-line the serial-
      number!).

   o  an identity of device, or the domain owner in the form of the domain trust
      anchor.  However, this is has not paid a global PKI anchored name within yearly
       support amount, and the WebPKI, so this identity could be pseudonymous.  If there manufacturer refuses to issue new
       vouchers at that point.  This last case is
      sales channel integration, then not new to the MASA will
       industry: many license systems are already deployed that have authenticated
       significantly worse effect.

   This section has outlined five situations in which a manufacturer
   could use the domain owner, either voucher system to enforce what are clearly license
   terms.  A manufacturer that attempted to enforce license terms via pinned certificate, or perhaps
      another HTTP authentication method,
   vouchers would find it rather ineffective as per Section 5.5.3.

   o the time terms would only be
   enforced when the device is activated,

   o  the IP address of the domain Owner's Registrar.  For ISPs enrolled, and
      Enterprises, the IP address provides very clear geolocation of the
      owner.  No amount of IP address privacy extensions ([RFC4941]) can
      do anything about this, as this is not (to repeat), a simple whois lookup likely identifies
      the ISP
   daily or Enterprise from the upper bits anyway.  A passive
      attacker who observes the connection definitely even monthly occurrence.

10.4.  Manufacturers and Grey market equipment

   Manufacturers of devices often sell different products into different
   regional markets.  Which product is available in which market can be
   driven by price differentials, support issues (some markets may conclude that
      the given enterprise/ISP is a customer of
   require manuals and tech-support to be done in the particular equipment
      vendor.  The precise model that is being enrolled will remain
      private.

   The above situation local language),
   government export regulation (such as whether strong crypto is
   permitted to be distinguished from exported, or permitted to be used in a residential/
   individual person who registers particular
   market).  When an domain owner obtains a device from a manufacturer: that an
   enterprise/ISP purchases routing products is hardly worth mentioning.
   Deviations would, however, different
   market (they can be notable.

   The situation is not improved by the enterprise/ISP using
   anonymization services such as ToR [Dingledine2004], as new) and transfers it to a TLS 1.2
   connection will reveal the ClientCertificate used, clearly
   identifying the enterprise/ISP involved.  TLS 1.3 is better in different location,
   this
   regard, but an active attacker can still discover the parties
   involved by performing a Man-In-The-Middle-Attack on the first
   attempt (breaking/killing it with is called a TCP RST), and then letting
   subsequent connection pass through. Grey Market.

   A manufacturer could attempt decide not to mix the BRSKI-MASA traffic in with
   general traffic issue a voucher to an enterprise/
   ISP based upon their site by hosting the MASA behind the same (set) location.  There are a number of load balancers that ways which this
   could be determined: from the companies normal marketing site is hosted
   behind.  This makes lots geolocation of sense the registrar, from
   sales channel knowledge about the customer, and what products are
   (un-)available in that market.  If the device has a straight capacity planning
   point GPS the
   coordinates of view as the same set device could even be placed into an extension of services (and
   the same set of
   Distributed Denial voucher.

   The above actions are not illegal, and not new.  Many manufacturers
   have shipped crypto-weak (exportable) versions of Service mitigations) may be used.
   Unfortunately, firmware as the BRSKI-MASA connections include TLS
   ClientCertificate exchanges, this may easily be observed in TLS 1.2,
   default on equipment for decades.  The first task of an enterprise/
   ISP has always been to login to a manufacturer system, show one's
   "entitlement" (country information, proof that support payments have
   been made), and receive either a traffic analysis may reveal it even in TLS 1.3.  This does not
   make such new updated firmware, or a plan irrelevant.  There may be other organizational
   reasons to keep license
   key that will activate the marketing site (which is often subject to
   frequent re-designs, outsourcing, etc.) separate from correct firmware.

   BRSKI permits the MASA, which
   may need above process to operate reliably for decades.

10.3.  Manufacturers automated (in an autonomic
   fashion), and Used or Stolen Equipment

   As explained above, therefore perhaps encourages this kind of
   differentiation by reducing the manufacturer receives information each time cost of doing it.

   An issue that manufacturers will need to deal with in the above
   automated process is when a device which is in factory-default mode does a zero-touch
   bootstrap, and attempts shipped to enroll into a one country with one
   set of rules (or laws or entitlements), but the domain owner's registrar. registry is in
   another one.  Which rules apply is something will have to be worked
   out: the manufacturer could come to believe they are dealing with
   Grey market equipment, when it is simply dealing with a global
   enterprise.

10.5.  Some mitigations for meddling by manufacturers

   The manufacturer most obvious mitigation is therefore in a position to decline not to issue a
   voucher if it detects that buy the new owner is product.  Pick
   manufacturers that are up-front about their policies, who do not
   change them gratuitiously.

   A manufacturer could provide a mechanism to manage the same trust anchors
   and built-in certificates (IDevID) as the
   previous owner.

   1. an extension.  This can be seen as is a feature if
   substantial amount of work, and may be an area for future
   standardization work.

   Replacement of the equipment is believed voucher validation anchors (usually pointing to
       have been stolen.  If the legitimate owner notifies
   the
       manufacturer original manufacturer's MASA) with those of the theft, then when the new owner brings the
       device up, if they use the zero-touch mechanism, permits
   the new
       (illegitimate) owner reveals their location and identity.

   2.  In the case of Used equipment, the initial owner could inform the
       manufacturer of the sale, or the manufacturer may just permit
       resales unless told otherwise.  In which case, the transfer of
       ownership simply occurs.

   3.  A manufacturer could however decide not to issue a new voucher in
       response vouchers to a transfer of ownership. subsequent owners.  This is essentially the
       same as the stolen case, with the manufacturer would be
   done by having decided
       that the sale was not legitimate.

   4.  There is selling (old) owner to run a fourth case, if MASA.

   In order to automatically find the manufacturer new MASA, the mechanism describe
   in this document is providing
       protection against stolen devices.  The to look for the MASA URL extension in the IDevID.
   A new owner could override this in their Registrar, or the
   manufacturer then has could provide a
       responsibility mechanism to protect update or replace the legitimate owner against fraudulent
       claims that
   IDevID prior to sale.

   Once the equipment was stolen.  Such a claim would cause voucher trust anchor and the IDevID is replaced, then the
   device will no longer trust the manufacturer to refuse to issue in any way.  When a new voucher.  Should
   owner performs a bootstrap, the device go through will point to a deep factory reset (for instance, replacement
       of MASA that has
   been chosen, and will validate vouchers from this new entity.

   The BRSKI protocol depends upon a damaged main board component, trust anchor on the device would not
       bootstrap.

   5.  Finally, there is a fifth case: and an
   identity on the manufacturer has decided device.  Management of these entities facilitates a
   few new operational modes without making any changes to
       end-of-line the device, or BRSKI
   protocol.  Those modes include: offline modes where the domain owner has not paid
   operates an internal MASA for all devices, resell modes where the
   first domain owner becomes the MASA for the next (resold-to) domain
   owner, and services where an aggregator acquires a yearly
       support amount, large variety of
   devices, and the manufacturer refuses then acts as a pseudonymized MASA for a variety of
   devices from a variety of manufacturers.

   Some manufacturers may wish to issue new
       vouchers at consider replacement of the IDevID as
   an indication that point.  This last case the device's warrantee is not new to terminated.  For others,
   the
       industry: many license systems are already deployed that have
       significantly worse effect.

   This section has outlined five situations in which privacy requirements of some deployments might consider this a manufacturer
   standard operating practice.

   As discussed at the end of Section 5.8.1, new work could be done to
   use a distributed consensus technology for the voucher system to enforce what are clearly license
   terms.  A manufacturer that attempted to enforce license terms via
   vouchers audit log.  This would find it rather ineffective as
   permit the terms would only audit log to continue to be
   enforced useful, even when the device is enrolled, and this there is not (to repeat), a
   daily or even monthly occurrence.

10.4.  Manufacturers and Grey market equipment

   Manufacturers
   chain of devices often sell different products into different
   regional markets.  Which product is available MASA due to changes of ownership.

11.  Security Considerations

   This document details a protocol for bootstrapping that balances
   operational concerns against security concerns.  As detailed in which market can be
   driven by price differentials, support issues (some markets may
   require manuals the
   introduction, and tech-support to be done touched on again in Section 7, the local language),
   government export regulation (such as whether strong crypto is
   permitted protocol allows
   for reduced security modes.  These attempt to be exported, or permitted deliver additional
   control to be used in a particular
   market).  When an domain the local administrator and owner obtains a device from in cases where less
   security provides operational benefits.  This section goes into more
   detail about a different
   market (they can be new) variety of specific considerations.

   To facilitate logging and transfers it administrative oversight, in addition to a different location,
   this is called a Grey Market.

   A manufacturer could decide not
   triggering Registrar verification of MASA logs, the pledge reports on
   voucher parsing status to issue the registrar.  In the case of a voucher failure,
   this information is informative to an enterprise/
   ISP based upon their location.  There are a number potentially malicious registrar.
   This is mandated anyway because of ways which this
   could be determined: from the geolocation operational benefits of an
   informed administrator in cases where the registrar, from
   sales channel knowledge about failure is indicative of a
   problem.  The registrar is RECOMMENDED to verify MASA logs if voucher
   status telemetry is not received.

   To facilitate truly limited clients EST RFC7030 section 3.3.2
   requirements that the customer, and what products are
   (un-)available client MUST support a client authentication
   model have been reduced in Section 7 to a statement that market.  If the device has
   registrar "MAY" choose to accept devices that fail cryptographic
   authentication.  This reflects current (poor) practices in shipping
   devices without a GPS cryptographic identity that are NOT RECOMMENDED.

   During the
   coordinates provisional period of the device could even be placed into an extension of connection the voucher.

   The above actions are not illegal, pledge MUST treat
   all HTTP header and content data as untrusted data.  HTTP libraries
   are regularly exposed to non-secured HTTP traffic: mature libraries
   should not new.  Many manufacturers have shipped crypto-weak (exportable) versions of firmware as the
   default on equipment for decades.  The first task of an enterprise/
   ISP has always been any problems.

   Pledges might chose to login engage in protocol operations with multiple
   discovered registrars in parallel.  As noted above they will only do
   so with distinct nonce values, but the end result could be multiple
   vouchers issued from the MASA if all registrars attempt to claim the
   device.  This is not a manufacturer system, show one's
   "entitlement" (country information, proof that support payments have
   been made), failure and receive either a new updated firmware, or a license
   key that will activate the correct firmware.

   BRSKI permits the above process pledge choses whichever
   voucher to automated (in an autonomic
   fashion), accept based on internal logic.  The registrars verifying
   log information will see multiple entries and therefore perhaps encourages take this kind into account
   for their analytics purposes.

11.1.  Denial of
   differentiation by reducing Service (DoS) against MASA

   There are uses cases where the cost of doing it.

   An issue that manufacturers will need MASA could be unavailable or
   uncooperative to deal with in the above
   automated process is when a device is shipped Registrar.  They include active DoS attacks,
   planned and unplanned network partitions, changes to one country with one
   set of rules (or laws MASA policy, or entitlements), but
   other instances where MASA policy rejects a claim.  These introduce
   an operational risk to the domain registry is Registrar owner in
   another one.  Which rules apply is something will have to be worked
   out: that MASA behavior
   might limit the manufacturer could come ability to believe bootstrap a pledge device.  For example
   this might be an issue during disaster recovery.  This risk can be
   mitigated by Registrars that request and maintain long term copies of
   "nonceless" vouchers.  In that way they are dealing with
   Grey market equipment, when guaranteed to be able to
   bootstrap their devices.

   The issuance of nonceless vouchers themselves creates a security
   concern.  If the Registrar of a previous domain can intercept
   protocol communications then it is simply dealing with can use a previously issued nonceless
   voucher to establish management control of a global
   enterprise.

10.5.  Some mitigations for meddling by manufacturers

   The most obvious mitigation pledge device even after
   having sold it.  This risk is not to buy mitigated by recording the product.  Pick
   manufacturers issuance of
   such vouchers in the MASA audit log that are up-front about their policies, who do not
   change them gratuitiously.

   A manufacturer could provide a mechanism to manage is verified by the trust anchors
   subsequent Registrar and built-in certificates (IDevID) as an extension. by Pledges only bootstrapping when in a
   factory default state.  This is reflects a
   substantial amount balance between enabling MASA
   independence during future bootstrapping and the security of work,
   bootstrapping itself.  Registrar control over requesting and may be auditing
   nonceless vouchers allows device owners to choose an area for future
   standardization work.

   Replacement appropriate
   balance.

   The MASA is exposed to DoS attacks wherein attackers claim an
   unbounded number of the voucher validation anchors (usually pointing devices.  Ensuring a registrar is representative
   of a valid manufacturer customer, even without validating ownership
   of specific pledge devices, helps to mitigate this.  Pledge
   signatures on the original manufacturer's MASA) with those pledge voucher-request, as forwarded by the
   registrar in the prior-signed-voucher-request field of the new owner permits registrar
   voucher-request, significantly reduce this risk by ensuring the new owner to issue vouchers to subsequent owners.  This would be
   done MASA
   can confirm proximity between the pledge and the registrar making the
   request.  Supply chain integration ("know your customer") is an
   additional step that MASA providers and device vendors can explore.

11.2.  Freshness in Voucher-Requests

   A concern has been raised that the pledge voucher-request should
   contain some content (a nonce) provided by having the selling (old) owner to run a MASA.

   In registrar and/or MASA
   in order for those actors to automatically find the new MASA, verify that the mechanism describe
   in this document pledge voucher-request
   is to look for fresh.

   There are a number of operational problems with getting a nonce from
   the MASA URL extension in to the IDevID.
   A new owner could override this in their Registrar, or pledge.  It is somewhat easier to collect a random
   value from the
   manufacturer could provide registrar, but as the registrar is not yet vouched
   for, such a mechanism registrar nonce has little value.  There are privacy and
   logistical challenges to update or replace the
   IDevID prior addressing these operational issues, so if
   such a thing were to sale.

   Once be considered, it would have to provide some
   clear value.  This section examines the voucher trust anchor and impacts of not having a fresh
   pledge voucher-request.

   Because the IDevID registrar authenticates the pledge, a full Man-in-the-
   Middle attack is replaced, then not possible, despite the
   device will no longer trust provisional TLS
   authentication by the manufacturer in any way.  When a new
   owner performs a bootstrap, pledge (see Section 5.)  Instead we examine the device will point to
   case of a MASA fake registrar (Rm) that has
   been chosen, and will validate vouchers from this new entity.

   The BRSKI protocol depends upon a trust anchor on communicates with the device and an
   identity on pledge in
   parallel or in close time proximity with the device.  Management of these entities facilitates intended registrar.
   (This scenario is intentionally supported as described in
   Section 4.1.)

   The fake registrar (Rm) can obtain a
   few new operational modes without making any changes to the BRSKI
   protocol.  Those modes include: offline modes where voucher signed by the domain owner
   operates an internal MASA for all devices, resell modes where the
   first domain owner becomes
   either directly or through arbitrary intermediaries.  Assuming that
   the MASA for accepts the next (resold-to) domain
   owner, and services where an aggregator acquires a large variety of
   devices, and then acts as registrar voucher-request (either because Rm is
   collaborating with a pseudonymized legitimate registrar according to supply chain
   information, or because the MASA for is in audit-log only mode), then a variety of
   devices from
   voucher linking the pledge to the registrar Rm is issued.

   Such a variety of manufacturers.

   Some manufacturers may wish voucher, when passed back to consider replacement of the IDevID as pledge, would link the pledge
   to registrar Rm, and would permit the pledge to end the provisional
   state.  It now trusts Rm and, if it has any security vulnerabilities
   leveragable by an indication that Rm with full administrative control, can be assumed
   to be a threat against the device's warrantee intended registrar.

   This flow is terminated.  For others, mitigated by the privacy requirements of some deployments intended registrar verifying the audit
   logs available from the MASA as described in Section 5.8.  Rm might consider this
   chose to collect a
   standard operating practice.

   As discussed at voucher-request but wait until after the end of Section 5.8.1, new work could intended
   registrar completes the authorization process before submitting it.
   This pledge voucher-request would be done 'stale' in that it has a nonce
   that no longer matches the internal state of the pledge.  In order to
   successfully use a distributed consensus technology for any resulting voucher the audit log.  This Rm would
   permit the audit log to continue need to be useful, even when there is a
   chain remove
   the stale nonce or anticipate the pledge's future nonce state.
   Reducing the possibility of MASA due this is why the pledge is mandated to changes of ownership.

11.  Security Considerations

   This document details
   generate a protocol for bootstrapping that balances
   operational concerns against security concerns.  As detailed strong random or pseudo-random number nonce.

   Additionally, in order to successfully use the
   introduction, and touched on again in Section 7, resulting voucher the protocol allows
   for reduced security modes.  These attempt to deliver additional
   control
   Rm would have to attack the local administrator pledge and owner in cases where less
   security provides operational benefits.  This section goes into more
   detail about return it to a variety bootstrapping
   enabled state.  This would require wiping the pledge of specific considerations.

   To facilitate logging current
   configuration and administrative oversight, in addition to triggering Registration verification a re-bootstrapping of MASA logs, the pledge reports
   on voucher parsing status to the registrar.  In the case pledge.  This
   is no more likely than simply taking control of a
   failure, the pledge directly
   but if this information is informative to a potentially malicious
   registrar.  This consideration the target network is mandated anyway because RECOMMENDED to
   take the following steps:

   o  Ongoing network monitoring for unexpected bootstrapping attempts
      by pledges.

   o  Retrieval and examination of MASA log information upon the operational
   benefits
      occurence of an informed administrator any such unexpected events.  Rm will be listed in cases where the failure is
   indicative of a problem.
      logs along with nonce information for analysis.

11.3.  Trusting manufacturers

   The registrar is RECOMMENDED BRSKI extensions to verify MASA
   logs if voucher status telemetry is not received.

   To facilitate truly limited clients EST RFC7030 section 3.3.2
   requirements that the client MUST support permit a client authentication
   model have been reduced new pledge to be completely
   configured with domain specific trust anchors.  The link from built-
   in Section 7 manufacturer-provided trust anchors to domain-specific trust
   anchors is mediated by the signed voucher artifact.

   If the manufacturer's IDevID signing key is not properly validated,
   then there is a statement risk that the
   registrar "MAY" choose to network will accept devices that fail cryptographic
   authentication.  This reflects current (poor) practices in shipping
   devices without a cryptographic identity pledge that are NOT RECOMMENDED.

   During
   should not be a member of the provisional period network.  As the address of the connection
   manufacturer's MASA is provided in the IDevID using the extension
   from Section 2.3, the malicious pledge MUST treat
   all HTTP header and content data as untrusted data.  HTTP libraries
   are regularly exposed to non-secured HTTP traffic: mature libraries
   should not have any problems.

   Pledges might chose to engage in protocol operations with multiple
   discovered registrars in parallel.  As noted above they will only do
   so have no problem
   collaborating with distinct nonce values, but it's MASA to produce a completely valid voucher.

   BRSKI does not, however, fundamentally change the end result could be multiple
   vouchers issued trust model from
   domain owner to manufacturer.  Assuming that the MASA if all registrars attempt pledge used its
   IDevID with RFC7030 EST and BRSKI, the domain (registrar) still needs
   to claim trust the
   device.  This manufacturer.

   Establishing this trust between domain and manufacturer is not outside
   the scope of BRSKI.  There are a failure number of mechanisms that can
   adopted including:

   o  Manually configuring each manufacturer's trust anchor.

   o  A Trust-On-First-Use (TOFU) mechanism.  A human would be queried
      upon seeing a manufacturer's trust anchor for the first time, and
      then the pledge choses whichever
   voucher trust anchor would be installed to accept based on internal logic.  The registrars verifying
   log information will see multiple entries and take this into account
   for their analytics purposes.

11.1.  DoS against MASA the trusted store.
      There are uses cases where risks with this; even if the MASA could be unavailable or
   uncooperative key to name mapping is
      validated using something like the Registrar.  They include active DoS attacks,
   planned and unplanned network partitions, changes to MASA policy, or
   other instances where MASA policy rejects a claim.  These introduce
   an operational risk to WebPKI, there remains the Registrar owner in
      possibility that MASA behavior
   might limit the ability to bootstrap name is a pledge device.  For example
   this might be an issue during disaster recovery.  This risk can be
   mitigated by Registrars that request and maintain long term copies of
   "nonceless" vouchers.  In look alike: e.g, dem0.example. vs
      demO.example.

   o  scanning the trust anchor from a QR code that way they came with the
      packaging (this is really a manual TOFU mechanism)

   o  some sales integration process where trust anchors are guaranteed to be able to
   bootstrap their devices.

   The issuance provided as
      part of nonceless vouchers themselves creates a security
   concern.  If the Registrar of a previous domain can intercept
   protocol communications then it can use sales process, probably included in a previously issued nonceless
   voucher to establish management control digital packing
      "slip", or a sales invoice.

   o  consortium membership, where all manufacturers of a pledge particular
      device even after
   having sold it. category (e.g, a light bulb, or a cable-modem) are signed
      by an certificate authority specifically for this.  This risk is mitigated done
      by recording the issuance of
   such vouchers in the MASA audit log that CableLabs today.  It is verified by the
   subsequent Registrar used for authentication and by Pledges only bootstrapping when in a
   factory default state.  This reflects
      authorization as part of TR-79: [docsisroot] and [TR069].

   The existing WebPKI provides a balance reasonable anchor between enabling MASA
   independence during future bootstrapping manufacturer
   name and public key.  It authenticates the security of
   bootstrapping itself.  Registrar control over requesting and auditing
   nonceless vouchers allows device owners to choose an appropriate
   balance.

   The MASA is exposed to DoS attacks wherein attackers claim an
   unbounded number of devices.  Ensuring key.  It does not provide
   a registrar reasonable authorization for the manufacturer, so it is representative not
   directly useable on it's own.

11.4.  Manufacturer Maintenance of a valid trust anchors

   BRSKI depends upon the manufacturer customer, even without validating ownership
   of specific pledge devices, helps building in trust anchors to mitigate this.  Pledge
   signatures on the
   pledge voucher-request, as forwarded by the
   registrar in the prior-signed-voucher-request field of the registrar
   voucher-request, significantly reduce this risk device.  The voucher artifact which is signed by ensuring the MASA
   can confirm proximity between will
   be validated by the pledge and using that anchor.  This implies that the registrar making
   manufacturer needs to maintain access to a signing key that the
   pledge can validate.

   The manufacturer will need to maintain the
   request.  This mechanism is optional ability to allow for constrained
   devices.  Supply chain integration ("know your customer") is an
   additional step make signatures
   that MASA providers and device vendors can explore.

11.2.  Freshness in Voucher-Requests

   A concern has been raised be validated for the lifetime that the pledge voucher-request should
   contain some content (a nonce) provided by device could be
   onboarded.  Whether this onboarding lifetime is less than the registrar and/or MASA device
   lifetime depends upon how the device is used.  An inventory of
   devices kept in order a warehouse as spares might not be onboarded for those actors many
   decades.

   There are good cryptographic hygiene reasons why a manufacturer would
   not want to verify maintain access to a private key for many decades.  A
   manufacturer in that situation can leverage a long-term certificate
   authority anchor, built-in to the pledge voucher-request pledge, and then a certificate
   chain may be incorporated using the normal CMS certificate set.  This
   may increase the size of the voucher artifacts, but that is fresh. not a
   significant issues in non-constrained environments.

   There are a number of few other operational problems with getting a nonce from variations that manufacturers could
   consider.  For instance, there is no reason that every device need
   have the MASA to same set of trust anchors pre-installed.  Devices built in
   different factories, or on different days, or any other consideration
   could have different trust anchors built in, and the pledge.  It record of which
   batch the device is somewhat easier in would be recorded in the asset database.  The
   manufacturer would then know which anchor to collect a random
   value sign an artifact
   against.

   Aside from the registrar, but as the registrar is not yet vouched
   for, such a registrar nonce has little value.  There are privacy and
   logistical challenges concern about long-term access to addressing these operational issues, so if
   such private keys, a thing were to be considered, it would have to provide some
   clear value.  This section examines
   major limiting factor for the impacts shelf-life of not having a fresh
   pledge voucher-request.

   Because many devices will be the registrar authenticates
   age of the pledge, a full Man-in-the-
   Middle attack is cryptographic algorithms included.  A device produced in
   2019 will have hardware and software capable of validating algorithms
   common in 2019, and will have no defense against attacks (both
   quantum and von-neuman brute force attacks) which have not possible, despite the provisional TLS
   authentication by yet been
   invented.  This concern is orthogonal to the pledge (see Section 5.)  Instead we examine concern about access to
   private keys, but this concern likely dominates and limits the
   case
   lifespan of a fake registrar (Rm) that communicates with the pledge in
   parallel or device in close time proximity with a warehouse.  If any update to firmware to
   support new cryptographic mechanism were possible (while the intended registrar.
   (This scenario is intentionally supported as described device
   was in
   Section 4.1.)

   The fake registrar (Rm) can obtain a voucher signed by warehouse), updates to trust anchors would also be done at
   the MASA
   either directly or through arbitrary intermediaries.  Assuming that same time.

   The set of standard operating proceedures for maintaining high value
   private keys is well documented.  For instance, the MASA accepts WebPKI provides a
   number of options for audits at {{cabforumaudit}}, and the registrar voucher-request (either because Rm DNSSEC
   root operations are well documented at {{dnssecroot}}.

   It is
   collaborating with a legitimate registrar according to supply chain
   information, not clear if Manufacturers will take this level of precaution,
   or because how strong the economic incentives are to maintain an appropriate
   level of security.

   This next section examines the risk due to a compromised MASA key.
   This is in audit-log only mode), then followed by examination of the risk of a
   voucher linking compromised
   manufacturer IDevID signing key.  The third section sections below
   examines the pledge to situation where MASA web server itself is under attacker
   control, but that the registrar Rm MASA signing key itself is issued.

   Such safe in a voucher, when passed back not-
   directly connected hardware module.

11.4.1.  Compromise of Manufacturer IDevID signing keys

   An attacker that has access to the pledge, would link the pledge
   to registrar Rm, and would permit key that the pledge manufacturer uses to end the provisional
   state.  It now trusts Rm and, if it has any security vulnerabilities
   leveragable by an Rm with full administrative control,
   sign IDevID certificates can be assumed create counterfeit devices.  Such
   devices can claim to be from a threat against the intended registrar.

   This flow is mitigated by the intended registrar verifying particular manufacturer, but be
   entirely different devices: Trojan horses in effect.

   As the audit
   logs available from attacker controls the MASA as described URL in Section 5.8.  Rm might
   chose to collect a voucher-request but wait until after the intended certificate, the
   registrar completes can be convinced to talk to the authorization process before submitting it.
   This pledge voucher-request would attackers' MASA.  The
   Registrar does not need to be 'stale' in that it has a nonce
   that no longer matches the internal state any kind of the pledge. promiscuous mode to be
   vulnerable.

   In order addition to
   successfully use any resulting voucher creating fake devices, the Rm would need attacker may also be able
   to remove
   the stale nonce or anticipate the pledge's future nonce state.
   Reducing issue revocations for existing certificates if the possibility of IDevID
   certificate process relies upon CRL lists that are distributed.

   There does not otherwise seem to be any risk from this is why the pledge is mandated compromise to
   generate a strong random
   devices which are already deployed, or pseudo-random number nonce.

   Additionally, which are sitting locally in order
   boxes waiting for deployment (local spares).  The issue is that
   operators will be unable to successfully use the resulting voucher the
   Rm would trust devices which have been in an
   uncontrolled warehouse as they do not know if those are real devices.

11.4.2.  Compromise of MASA signing keys

   There are two periods of time in which to attack consider: when the pledge and return it to a bootstrapping
   enabled state.  This would require wiping MASA key
   has fallen into the pledge hands of current
   configuration an attacker, and triggering a re-bootstrapping of the pledge.  This
   is no more likely than simply taking control of after the pledge directly
   but if this is a consideration MASA
   recognizes that the target network is RECOMMENDED key has been compromised.

11.4.2.1.  Attacker opportunties with compromised MASA key

   An attacker that has access to
   take the following steps:

   o  Ongoing network monitoring for unexpected bootstrapping attempts
      by pledges.

   o  Retrieval and examination of MASA log information upon the
      occurence of any such unexpected events.  Rm will signing key could create
   vouchers.  These vouchers could be listed in the
      logs along with nonce information for analysis.

11.3.  Trusting manufacturers

   The BRSKI extensions existing deployed devices, or
   for devices which are still in a warehouse.  In order to exploit
   these vouchers two things need to EST permit occur: the device has to go through
   a new pledge factory default boot cycle, and the registrar has to be completely
   configured with domain specific trust anchors.  The link from built-
   in manufacturer-provided trust anchors convinced
   to domain-specific trust
   anchors is mediated by contact the signed voucher artifact. attacker's MASA.

   If the manufacturer's IDevID signing key attacker controls a Registrar which is not properly validated, visible to the device,
   then there is a risk that the network will accept a pledge that
   should not be a member no difficulty in delivery of the network.  As the address false voucher.  A
   possible practical example of the
   manufacturer's MASA is provided an attack like this would be in a data
   center, at an ISP peering point (whether a public IX, or a private
   peering point).  In such a situation, there are already cables
   attached to the IDevID using equipment that lead to other devices (the peers at
   the extension
   from Section 2.3, IX), and through those links, the malicious pledge will false voucher could be
   delivered.  The difficult part would be get the device put through a
   factory reset.  This might be accomplished through social engineering
   of data center staff.  Most locked cages have no problem
   collaborating with it's MASA ventilation holes, and
   possibly a long "paperclip" could reach through to produce depress a completely valid voucher.

   BRSKI does not, however, fundamentally change the trust model from
   domain owner factory
   reset button.  Once such a piece of ISP equipment has been
   compromised, it could be used to manufacturer.  Assuming compromise equipment that the pledge used its
   IDevID was
   connected to (through long haul links even), assuming that those
   pieces of equipment could also be forced through a factory reset.

   The above scenario seems rather unlikely as it requires some element
   of physical access; but were there a remote exploit that did not
   cause a direct breach, but rather a fault that resulted in a factory
   reset, this could provide a reasonable path.

   The above deals with RFC7030 EST and BRSKI, ANI uses of BRSKI.  For cases where 802.11 or
   802.15.4 is involved, the domain (registrar) still needs need to connect directly to trust the manufacturer.

   Establishing this trust between domain and manufacturer device is outside
   eliminated, but the scope of BRSKI.  There are need to do a number factory reset is not.  Physical
   possession of mechanisms the device is not required as above, provided that can
   adopted including:

   o  Manually configuring each manufacturer's trust anchor.

   o  A Trust-On-First-Use (TOFU) mechanism.  A human would be queried
      upon seeing
   there is some way to force a manufacturer's trust anchor for the first time, and
      then factory reset.  With some consumers
   devices with low overall implementation quality, the trust anchor would end users might
   be installed familiar with needing to reset the trusted store.
      There device regularly.

   The authors are risks unable to come up with this; even if the key an attack scenario where a
   compromised voucher signature enables an attacker to name introduce a
   compromised pledge into an existing operator's network.  This is validated
      using something like the WebPKI, there remains
   case because the possibility
      that operator controls the name communication between
   Registrar and MASA, and there is a look alike: e.g, dem0.example. vs demO.example.

   o  scanning no opportunity to introduce the trust anchor from a QR code fake
   voucher through that came with the
      packaging (this conduit.

11.4.2.2.  Risks after key compromise is really a manual TOFU mechanism)

   o  some sales integration process where trust anchors are provided as
      part of known

   Once the sales process, probably included in a digital packing
      "slip", or a sales invoice.

   o  consortium membership, where all manufacturers operator of the MASA realizes that the voucher signing key
   has been compromised it has to do a particular
      device category (e.g, a light bulb, or few things.

   First, it MUST issue a cable-modem) are signed
      by an certificate authority specifically for this.  This is done
      by CableLabs today.  It is used for authentication and
      authorization firmware update to all devices that had that
   key as part of TR-79: [docsisroot] and [TR069].

   The existing WebPKI provides a reasonable anchor between manufacturer
   name and public trust anchor, such that they will no longer trust vouchers
   from that key.  It authenticates  This will affect devices in the key.  It does field which are
   operating, but those devices, being in operation, are not provide
   a reasonable authorization for the manufacturer, performing
   onboarding operations, so it this is not
   directly useable on it's own.

11.4.  Manufacturer Maintenance of trust anchors

   BRSKI depends upon the manufacturer building a critical patch.

   Devices in trust anchors boxes (in warehouses) are vulnerable, and remain
   vulnerable until patched.  An operator would be prudent to unbox the
   pledge device.  The voucher artifact which is signed
   devices, onboard them in a safe environment, and then perform
   firmware updates.  This does not have to be done by the MASA will end-operator;
   it could be validated done by the pledge using that anchor.  This implies a distributor that stores the
   manufacturer needs to maintain access spares.  A
   recommended practice for high value devices (which typically have a
   <4hr service window) may be to validate the device operation on a signing key
   regular basis anyway.

   If the onboarding process includes attestations about firmware
   versions, then through that process the
   pledge can validate.

   The manufacturer will need operator would be advised to maintain
   upgrade the ability to make signatures
   that can be validated firmware before going into production.  Unfortunately,
   this does not help against situations where the attacker operates
   their own Registrar (as listed above).

   [RFC8366] section 6.1 explains the need for short-lived vouchers.
   The nonce guarantees freshness, and the short-lived nature of the lifetime
   voucher means that the device could be
   onboarded.  Whether this onboarding lifetime window to deliver a fake voucher is less than very
   short.  A nonceless, long-lived voucher would be the device
   lifetime depends upon how only option for
   the device is used.  An inventory of attacker, and devices kept in a the warehouse as spares might not be onboarded for many
   decades.

   There are good cryptographic hygiene reasons why a manufacturer would
   not want to maintain access be vulnerable to
   such a private thing.

   A key operational recommendation is for many decades.  A
   manufacturer in manufacturers to sign
   nonceless, long-lived vouchers with a different key that situation can leverage they sign
   short-lived vouchers.  That key needs significantly better
   protection.  If both keys come from a long-term certificate
   authority anchor, built-in to the pledge, and common trust-anchor (the
   manufacturer's CA), then a certificate
   chain may be incorporated using the normal CMS certificate set.  This
   may increase the size compromise of the voucher artifacts, but that is not manufacturer's CA would
   be a
   significant issues in non-constrained environments.

   There are bigger problem.

11.4.3.  Compromise of MASA web service

   An attacker that takes over the MASA web service has a few number of
   attacks.  The most obvious one is simply to take the database listing
   customers and devices and to sell this data to other operational variations attackers who
   will now know where to find potentially vulnerable devices.

   The second most obvious thing that manufacturers could
   consider.  For instance, there the attacker can do is no reason that every device need
   have to kill the same set of trust anchors pre-installed.  Devices built in
   different factories, or on different days,
   service, or any other consideration make it operate unreliably, making customers frustrated.
   This could have different trust anchors built in, a serious affect on ability to deploy new services by
   customers, and would be a significant issue during disaster recovery.

   While the record compromise of which
   batch the device is MASA web service may lead to the
   compromise of the MASA voucher signing key, if the signing occurs
   offboard (such as in would a hardware signing module, HSM), then the key
   may well be recorded in safe, but control over it resides with the asset database.  The
   manufacturer would then know which anchor attacker.

   Such an attacker can issue vouchers for any device presently in
   service.  Said device still needs to sign be convinced to do through a
   factory reset process before an artifact
   against.

   Aside from attack.

   If the concern about long-term attacker has access to private keys, a
   major limiting factor key that is trusted for long-lived
   nonceless vouchers, then they could issue vouchers for the shelf-life of many devices will be the
   age of the cryptographic algorithms included.  A device produced in
   2019 will have hardware and software capable of validating algorithms
   common in 2019, and will have no defense against attacks (both
   quantum and von-neuman brute force attacks) which have
   are not yet been
   invented. in service.  This concern is orthogonal to the concern about access attack may be very hard to
   private keys, but this concern likely dominates verify and limits the
   lifespan of a device in a warehouse.  If any update to
   as it would involve doing firmware to
   support new cryptographic mechanism were possible (while the updates on every device
   was in
   warehouses (a potentially ruinously expensive process), a warehouse), updates to trust anchors would also
   manufacturer might be done at
   the same time. reluctant to admit this possibility.

12.  Acknowledgements

   We would like to thank the various reviewers for their input, in
   particular William Atwood, Brian Carpenter, Toerless Eckert, Fuyu Eleven, Eliot Lear,
   Sergey Kasatkin, Anoop Kumar, Markus Stenberg, Peter van der Stok,
   and Thomas Werner

   Significant reviews were done by Jari Arko, Christian Huitema and
   Russ Housley.

   This document started it's life as a two-page idea from Steinthor
   Bjarnason.

   In addition, significant review comments were receives by many IESG
   members, including Adam Roach, Alexey Melnikov, Alissa Cooper,
   Benjamin Kaduk, Eric Vyncke, Roman Danyliw, and Magnus Westerlund.

13.  References

13.1.  Normative References

   [cabforumaudit]
              "Information for Auditors and Assessors", August 2019,
              <https://cabforum.org/
              information-for-auditors-and-assessors/>.

   [dnssecroot]
              "DNSSEC Practice Statement for the Root Zone ZSK
              Operator", December 2017,
              <https://www.iana.org/dnssec/dps/zsk-operator/
              dps-zsk-operator-v2.0.pdf>.

   [I-D.ietf-anima-autonomic-control-plane]
              Eckert, T., Behringer, M., and S. Bjarnason, "An Autonomic
              Control Plane (ACP)", draft-ietf-anima-autonomic-control-
              plane-19
              plane-20 (work in progress), March July 2019.

   [I-D.ietf-anima-grasp]
              Bormann, C., Carpenter, B., and B. Liu, "A Generic
              Autonomic Signaling Protocol (GRASP)", draft-ietf-anima-
              grasp-15 (work in progress), July 2017.

   [IDevID]   "IEEE 802.1AR Secure Device Identifier", December 2009,
              <http://standards.ieee.org/findstds/
              standard/802.1AR-2009.html>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC3748]  Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
              Levkowetz, Ed., "Extensible Authentication Protocol
              (EAP)", RFC 3748, DOI 10.17487/RFC3748, June 2004,
              <https://www.rfc-editor.org/info/rfc3748>.

   [RFC3927]  Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
              Configuration of IPv4 Link-Local Addresses", RFC 3927,
              DOI 10.17487/RFC3927, May 2005,
              <https://www.rfc-editor.org/info/rfc3927>.

   [RFC4086]  Eastlake 3rd, D., Schiller, J., and S. Crocker,
              "Randomness Requirements for Security", BCP 106, RFC 4086,
              DOI 10.17487/RFC4086, June 2005,
              <https://www.rfc-editor.org/info/rfc4086>.

   [RFC4519]  Sciberras, A., Ed., "Lightweight Directory Access Protocol
              (LDAP): Schema for User Applications", RFC 4519,
              DOI 10.17487/RFC4519, June 2006,
              <https://www.rfc-editor.org/info/rfc4519>.

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
              <https://www.rfc-editor.org/info/rfc4648>.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862,
              DOI 10.17487/RFC4862, September 2007,
              <https://www.rfc-editor.org/info/rfc4862>.

   [RFC4941]  Narten, T., Draves, R., and S. Krishnan, "Privacy
              Extensions for Stateless Address Autoconfiguration in
              IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
              <https://www.rfc-editor.org/info/rfc4941>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

   [RFC5272]  Schaad, J. and M. Myers, "Certificate Management over CMS
              (CMC)", RFC 5272, DOI 10.17487/RFC5272, June 2008,
              <https://www.rfc-editor.org/info/rfc5272>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <https://www.rfc-editor.org/info/rfc5280>.

   [RFC5386]  Williams, N. and M. Richardson, "Better-Than-Nothing
              Security: An Unauthenticated Mode of IPsec", RFC 5386,
              DOI 10.17487/RFC5386, November 2008,
              <https://www.rfc-editor.org/info/rfc5386>.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, DOI 10.17487/RFC5652, September 2009,
              <https://www.rfc-editor.org/info/rfc5652>.

   [RFC5660]  Williams, N., "IPsec Channels: Connection Latching",
              RFC 5660, DOI 10.17487/RFC5660, October 2009,
              <https://www.rfc-editor.org/info/rfc5660>.

   [RFC6125]  Saint-Andre, P. and J. Hodges, "Representation and
              Verification of Domain-Based Application Service Identity
              within Internet Public Key Infrastructure Using X.509
              (PKIX) Certificates in the Context of Transport Layer
              Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
              2011, <https://www.rfc-editor.org/info/rfc6125>.

   [RFC6762]  Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
              DOI 10.17487/RFC6762, February 2013,
              <https://www.rfc-editor.org/info/rfc6762>.

   [RFC6763]  Cheshire, S. and M. Krochmal, "DNS-Based Service
              Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
              <https://www.rfc-editor.org/info/rfc6763>.

   [RFC7030]  Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
              "Enrollment over Secure Transport", RFC 7030,
              DOI 10.17487/RFC7030, October 2013,
              <https://www.rfc-editor.org/info/rfc7030>.

   [RFC7159]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
              2014, <https://www.rfc-editor.org/info/rfc7159>.

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,
              <https://www.rfc-editor.org/info/rfc7230>.

   [RFC7231]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
              DOI 10.17487/RFC7231, June 2014,
              <https://www.rfc-editor.org/info/rfc7231>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/info/rfc7951>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

   [RFC8366]  Watsen, K., Richardson, M., Pritikin, M., and T. Eckert,
              "A Voucher Artifact for Bootstrapping Protocols",
              RFC 8366, DOI 10.17487/RFC8366, May 2018,
              <https://www.rfc-editor.org/info/rfc8366>.

   [RFC8368]  Eckert, T., Ed. and M. Behringer, "Using an Autonomic
              Control Plane for Stable Connectivity of Network
              Operations, Administration, and Maintenance (OAM)",
              RFC 8368, DOI 10.17487/RFC8368, May 2018,
              <https://www.rfc-editor.org/info/rfc8368>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC8610]  Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
              Definition Language (CDDL): A Notational Convention to
              Express Concise Binary Object Representation (CBOR) and
              JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
              June 2019, <https://www.rfc-editor.org/info/rfc8610>.

13.2.  Informative References

   [Dingledine2004]
              Dingledine, R., Mathewson, N., and P. Syverson, "Tor: the
              second-generation onion router", 2004,
              <https://spec.torproject.org/tor-spec>.

   [docsisroot]
              "CableLabs Digital Certificate Issuance Service", February
              2018, <https://www.cablelabs.com/resources/
              digital-certificate-issuance-service/>.

   [I-D.ietf-ace-coap-est]
              Stok, P., Kampanakis, P., Richardson, M., and S. Raza,
              "EST over secure CoAP (EST-coaps)", draft-ietf-ace-coap-
              est-12 (work in progress), June 2019.

   [I-D.ietf-anima-constrained-voucher]
              Richardson, M., Stok, P., and P. Kampanakis, "Constrained
              Voucher Artifacts for Bootstrapping Protocols", draft-
              ietf-anima-constrained-voucher-05 (work in progress), July
              2019.

   [I-D.ietf-anima-reference-model]
              Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L.,
              and J. Nobre, "A Reference Model for Autonomic
              Networking", draft-ietf-anima-reference-model-10 (work in
              progress), November 2018.

   [I-D.ietf-anima-stable-connectivity]
              Eckert, T. and M. Behringer, "Using Autonomic Control
              Plane for Stable Connectivity of Network OAM", draft-ietf-
              anima-stable-connectivity-10 (work in progress), February
              2018.

   [I-D.ietf-cbor-cddl]
              Birkholz, H., Vigano, C., and C. Bormann, "Concise data
              definition language (CDDL): a notational convention to
              express CBOR and JSON data structures", draft-ietf-cbor-
              cddl-08 (work in progress), March 2019.

   [I-D.ietf-netconf-zerotouch]
              Watsen, K., Abrahamsson, M., and I. Farrer, "Secure Zero
              Touch Provisioning (SZTP)", draft-ietf-netconf-
              zerotouch-29 (work in progress), January 2019.

   [I-D.ietf-opsawg-mud]
              Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
              Description Specification", draft-ietf-opsawg-mud-25 (work
              in progress), June 2018.

   [I-D.richardson-anima-state-for-joinrouter]
              Richardson, M., "Considerations for stateful vs stateless
              join router in ANIMA bootstrap", draft-richardson-anima-
              state-for-joinrouter-02 (work in progress), January 2018.

   [imprinting]
              "Wikipedia article: Imprinting", July 2015,
              <https://en.wikipedia.org/wiki/Imprinting_(psychology)>.

   [IoTstrangeThings]
              "IoT of toys stranger than fiction: Cybersecurity and data
              privacy update (accessed 2018-12-02)", March 2017,
              <https://www.welivesecurity.com/2017/03/03/
              internet-of-things-security-privacy-iot-update/>.

   [livingwithIoT]
              "What is it actually like to live in a house filled with
              IoT devices? (accessed 2018-12-02)", February 2018,
              <https://www.siliconrepublic.com/machines/
              iot-smart-devices-reality>.

   [RFC2473]  Conta, A. and S. Deering, "Generic Packet Tunneling in
              IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
              December 1998, <https://www.rfc-editor.org/info/rfc2473>.

   [RFC2663]  Srisuresh, P. and M. Holdrege, "IP Network Address
              Translator (NAT) Terminology and Considerations",
              RFC 2663, DOI 10.17487/RFC2663, August 1999,
              <https://www.rfc-editor.org/info/rfc2663>.

   [RFC5209]  Sangster, P., Khosravi, H., Mani, M., Narayan, K., and J.
              Tardo, "Network Endpoint Assessment (NEA): Overview and
              Requirements", RFC 5209, DOI 10.17487/RFC5209, June 2008,
              <https://www.rfc-editor.org/info/rfc5209>.

   [RFC5785]  Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
              Uniform Resource Identifiers (URIs)", RFC 5785,
              DOI 10.17487/RFC5785, April 2010,
              <https://www.rfc-editor.org/info/rfc5785>.

   [RFC6960]  Santesson, S., Myers, M., Ankney, R., Malpani, A.,
              Galperin, S., and C. Adams, "X.509 Internet Public Key
              Infrastructure Online Certificate Status Protocol - OCSP",
              RFC 6960, DOI 10.17487/RFC6960, June 2013,
              <https://www.rfc-editor.org/info/rfc6960>.

   [RFC6961]  Pettersen, Y., "The Transport Layer Security (TLS)
              Multiple Certificate Status Request Extension", RFC 6961,
              DOI 10.17487/RFC6961, June 2013,
              <https://www.rfc-editor.org/info/rfc6961>.

   [RFC7217]  Gont, F., "A Method for Generating Semantically Opaque
              Interface Identifiers with IPv6 Stateless Address
              Autoconfiguration (SLAAC)", RFC 7217,
              DOI 10.17487/RFC7217, April 2014,
              <https://www.rfc-editor.org/info/rfc7217>.

   [RFC7228]  Bormann, C., Ersue, M., and A. Keranen, "Terminology for
              Constrained-Node Networks", RFC 7228,
              DOI 10.17487/RFC7228, May 2014,
              <https://www.rfc-editor.org/info/rfc7228>.

   [RFC7231]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
              DOI 10.17487/RFC7231, June 2014,
              <https://www.rfc-editor.org/info/rfc7231>.

   [RFC7258]  Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
              Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
              2014, <https://www.rfc-editor.org/info/rfc7258>.

   [RFC7435]  Dukhovni, V., "Opportunistic Security: Some Protection
              Most of the Time", RFC 7435, DOI 10.17487/RFC7435,
              December 2014, <https://www.rfc-editor.org/info/rfc7435>.

   [RFC7575]  Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
              Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
              Networking: Definitions and Design Goals", RFC 7575,
              DOI 10.17487/RFC7575, June 2015,
              <https://www.rfc-editor.org/info/rfc7575>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8520]  Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
              Description Specification", RFC 8520,
              DOI 10.17487/RFC8520, March 2019,
              <https://www.rfc-editor.org/info/rfc8520>.

   [RFC8572]  Watsen, K., Farrer, I., and M. Abrahamsson, "Secure Zero
              Touch Provisioning (SZTP)", RFC 8572,
              DOI 10.17487/RFC8572, April 2019,
              <https://www.rfc-editor.org/info/rfc8572>.

   [slowloris]
              "Slowloris (computer security)", February 2019,
              <https://en.wikipedia.org/wiki/
              Slowloris_(computer_security)/>.

   [Stajano99theresurrecting]
              Stajano, F. and R. Anderson, "The resurrecting duckling:
              security issues for ad-hoc wireless networks", 1999,
              <https://www.cl.cam.ac.uk/~fms27/
              papers/1999-StajanoAnd-duckling.pdf>.

   [TR069]    "TR-69: CPE WAN Management Protocol", February 2018,
              <https://www.broadband-forum.org/standards-and-software/
              technical-specifications/tr-069-files-tools>.

   [W3C.WD-capability-urls-20140218]
              Tennison, J., "Good Practices for Capability URLs", World
              Wide Web Consortium WD WD-capability-urls-20140218,
              February 2014,
              <http://www.w3.org/TR/2014/WD-capability-urls-20140218>.

Appendix A.  IPv4 and non-ANI operations

   The secification of BRSKI in Section 4 intentionally only covers the
   mechanisms for an IPv6 pledge using Link-Local addresses.  This
   section describes non-normative extensions that can be used in other
   environments.

A.1.  IPv4 Link Local addresses

   Instead of an IPv6 link-local address, an IPv4 address may be
   generated using [RFC3927] Dynamic Configuration of IPv4 Link-Local
   Addresses.

   In the case that an IPv4 Link-Local address is formed, then the
   bootstrap process would continue as in the IPv6 case by looking for a
   (circuit) proxy.

A.2.  Use of DHCPv4

   The Plege MAY obtain an IP address via DHCP [RFC2131].  The DHCP
   provided parameters for the Domain Name System can be used to perform
   DNS operations if all local discovery attempts fail.

Appendix B.  mDNS / DNSSD proxy discovery options

   Pledge discovery of the proxy (Section 4.1) MAY be performed with
   DNS-based Service Discovery [RFC6763] over Multicast DNS [RFC6762] to
   discover the proxy at "_brski-proxy._tcp.local.".

   Proxy discovery of the registrar (Section 4.3) MAY be performed with
   DNS-based Service Discovery over Multicast DNS to discover registrars
   by searching for the service "_brski-registrar._tcp.local.".

   To prevent unaccceptable levels of network traffic, when using mDNS,
   the congestion avoidance mechanisms specified in [RFC6762] section 7
   MUST be followed.  The pledge SHOULD listen for an unsolicited
   broadcast response as described in [RFC6762].  This allows devices to
   avoid announcing their presence via mDNS broadcasts and instead
   silently join a network by watching for periodic unsolicited
   broadcast responses.

   Discovery of registrar MAY also be performed with DNS-based service
   discovery by searching for the service "_brski-
   registrar._tcp.example.com".
   registrar._tcp.<domain>".  In this case the domain "example.com" is
   discovered as described in [RFC6763] section 11 (Appendix A.2
   suggests the use of DHCP parameters).

   If no local proxy or registrar service is located using the GRASP
   mechanisms or the above mentioned DNS-based Service Discovery methods
   methods, the pledge MAY contact a well known manufacturer provided
   bootstrapping server by performing a DNS lookup using a well known
   URI such as "brski-registrar.manufacturer.example.com".  The details
   of the URI are manufacturer specific.  Manufacturers that leverage
   this method on the pledge are responsible for providing the registrar
   service.  Also see Section 2.7.

   The current DNS services returned during each query are maintained
   until bootstrapping is completed.  If bootstrapping fails and the
   pledge returns to the Discovery state, it picks up where it left off
   and continues attempting bootstrapping.  For example, if the first
   Multicast DNS _bootstrapks._tcp.local response doesn't work then the
   second and third responses are tried.  If these fail the pledge moves
   on to normal DNS-based Service Discovery.

Appendix C.  MUD Extension

   The following extension augments the MUD model to include a single
   node, as described in [I-D.ietf-opsawg-mud] [RFC8520] section 3.6, using the following
   sample module that has the following tree structure:

   module: ietf-mud-brski-masa
   augment /ietf-mud:mud:
   +--rw masa-server?   inet:uri

   The model is defined as follows:

   <CODE BEGINS> file "ietf-mud-extension@2018-02-14.yang" "ietf-mud-brski-masaurl-extension@2018-02-14.yang"
   module ietf-mud-brski-masa {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-mud-brski-masa";
     prefix ietf-mud-brski-masa;
     import ietf-mud {
       prefix ietf-mud;
     }
     import ietf-inet-types {
       prefix inet;
     }

     organization
       "IETF ANIMA (Autonomic Networking Integrated Model and
       Approach) Working Group";
       contact
       "WG Web: http://tools.ietf.org/wg/anima/
       WG List: anima@ietf.org
       ";
     description
       "BRSKI extension to a MUD file to indicate the
       MASA URL.";

     revision 2018-02-14 {
       description
       "Initial revision.";
       reference
       "RFC XXXX: Manufacturer Usage Description
       Specification";
     }

     augment "/ietf-mud:mud" {
       description
       "BRSKI extension to a MUD file to indicate the
       MASA URL.";
       leaf masa-server {
         type inet:uri;
         description
         "This value is the URI of the MASA server";
       }
     }
   }
   <CODE ENDS>

   The MUD extensions string "masa" is defined, and MUST be included in
   the extensions array of the mud container of a MUD file when this
   extension is used.

Appendix D.  Example Vouchers

   Three entities are involved in a voucher: the MASA issues (signs) it,
   the registrar's public key is mentioned in the voucher, and the
   pledge validates it.  In order to provide reproduceable examples the
   public and private keys for an example MASA and registrar are first
   listed.

D.1.  Keys involved

   The Manufacturer has a Certificate Authority that signs the pledge's
   IDevID.  In addition the Manufacturer's signing authority (the MASA)
   signs the vouchers, and that certificate must distributed to the
   devices at manufacturing time so that vouchers can be validated.

D.1.1.  MASA key pair for voucher signatures

   This private key signs vouchers:

   -----BEGIN EC PRIVATE KEY-----
   MIGkAgEBBDAgiRoYqKoEcfOfvRvmZ5P5Azn58tuI7nSnIy7OgFnCeiNo+BmbgMho
   r6lcU60gwVagBwYFK4EEACKhZANiAATZAH3Rb2FvIJOnts+vXuWW35ofyNbCHzjA
   zOi2kWZFE1ByurKImNcNMFGirGnRXIXGqWCfw5ICgJ8CuM3vV5ty9bf7KUlOkejz
   Tvv+5PV++elkP9HQ83vqTAws2WwWTxI=
   -----END EC PRIVATE KEY-----

   This public key validates vouchers:

   -----BEGIN CERTIFICATE-----
   MIIBzzCCAVagAwIBAgIBATAKBggqhkjOPQQDAjBNMRIwEAYKCZImiZPyLGQBGRYC
   Y2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xHDAaBgNVBAMME1Vuc3RydW5n
   IEhpZ2h3YXkgQ0EwHhcNMTcwMzI2MTYxOTQwWhcNMTkwMzI2MTYxOTQwWjBHMRIw
   EAYKCZImiZPyLGQBGRYCY2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xFjAU
   BgNVBAMMDVVuc3RydW5nIE1BU0EwdjAQBgcqhkjOPQIBBgUrgQQAIgNiAATZAH3R
   b2FvIJOnts+vXuWW35ofyNbCHzjAzOi2kWZFE1ByurKImNcNMFGirGnRXIXGqWCf
   w5ICgJ8CuM3vV5ty9bf7KUlOkejzTvv+5PV++elkP9HQ83vqTAws2WwWTxKjEDAO
   MAwGA1UdEwEB/wQCMAAwCgYIKoZIzj0EAwIDZwAwZAIwGb0oyM0doP6t3/LSPL5O
   DuatEwMYh7WGO+IYTHC8K7EyHBOmCYReKT2+GhV/CLWzAjBNy6UMJTt1tsxJsJqd
   MPUIFj+4wZg1AOIb/JoA6M7r33pwLQTrHRxEzVMGfWOkYUw=
   -----END CERTIFICATE-----

D.1.2.  Manufacturer key pair for IDevID signatures

   This private key signs IDevID certificates:

   -----BEGIN EC PRIVATE KEY-----
   MIGkAgEBBDAgiRoYqKoEcfOfvRvmZ5P5Azn58tuI7nSnIy7OgFnCeiNo+BmbgMho
   r6lcU60gwVagBwYFK4EEACKhZANiAATZAH3Rb2FvIJOnts+vXuWW35ofyNbCHzjA
   zOi2kWZFE1ByurKImNcNMFGirGnRXIXGqWCfw5ICgJ8CuM3vV5ty9bf7KUlOkejz
   Tvv+5PV++elkP9HQ83vqTAws2WwWTxI=
   -----END EC PRIVATE KEY-----

   This public key validates IDevID certificates:

   -----BEGIN CERTIFICATE-----
   MIIBzzCCAVagAwIBAgIBATAKBggqhkjOPQQDAjBNMRIwEAYKCZImiZPyLGQBGRYC
   Y2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xHDAaBgNVBAMME1Vuc3RydW5n
   IEhpZ2h3YXkgQ0EwHhcNMTcwMzI2MTYxOTQwWhcNMTkwMzI2MTYxOTQwWjBHMRIw
   EAYKCZImiZPyLGQBGRYCY2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xFjAU
   BgNVBAMMDVVuc3RydW5nIE1BU0EwdjAQBgcqhkjOPQIBBgUrgQQAIgNiAATZAH3R
   b2FvIJOnts+vXuWW35ofyNbCHzjAzOi2kWZFE1ByurKImNcNMFGirGnRXIXGqWCf
   w5ICgJ8CuM3vV5ty9bf7KUlOkejzTvv+5PV++elkP9HQ83vqTAws2WwWTxKjEDAO
   MAwGA1UdEwEB/wQCMAAwCgYIKoZIzj0EAwIDZwAwZAIwGb0oyM0doP6t3/LSPL5O
   DuatEwMYh7WGO+IYTHC8K7EyHBOmCYReKT2+GhV/CLWzAjBNy6UMJTt1tsxJsJqd
   MPUIFj+4wZg1AOIb/JoA6M7r33pwLQTrHRxEzVMGfWOkYUw=
   -----END CERTIFICATE-----

D.1.3.  Registrar key pair

   The registrar key (or chain) is the representative of the domain
   owner.  This key signs registrar voucher-requests:

   -----BEGIN EC PRIVATE KEY-----
   MHcCAQEEIF+obiToYYYeMifPsZvrjWJ0yFsCJwIFhpokmT/TULmXoAoGCCqGSM49
   AwEHoUQDQgAENWQOzcNMUjP0NrtfeBc0DJLWfeMGgCFdIv6FUz4DifM1ujMBec/g
   6W/P6boTmyTGdFOh/8HwKUerL5bpneK8sg==
   -----END EC PRIVATE KEY-----

   The public key is indicated in a pledge voucher-request to show
   proximity.

   -----BEGIN CERTIFICATE-----
   MIIBrjCCATOgAwIBAgIBAzAKBggqhkjOPQQDAzBOMRIwEAYKCZImiZPyLGQBGRYC
   Y2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xHTAbBgNVBAMMFFVuc3RydW5n
   IEZvdW50YWluIENBMB4XDTE3MDkwNTAxMTI0NVoXDTE5MDkwNTAxMTI0NVowQzES
   MBAGCgmSJomT8ixkARkWAmNhMRkwFwYKCZImiZPyLGQBGRYJc2FuZGVsbWFuMRIw
   EAYDVQQDDAlsb2NhbGhvc3QwWTATBgcqhkjOPQIBBggqhkjOPQMBBwNCAAQ1ZA7N
   w0xSM/Q2u194FzQMktZ94waAIV0i/oVTPgOJ8zW6MwF5z+Dpb8/puhObJMZ0U6H/
   wfApR6svlumd4ryyow0wCzAJBgNVHRMEAjAAMAoGCCqGSM49BAMDA2kAMGYCMQC3
   /iTQJ3evYYcgbXhbmzrp64t3QC6qjIeY2jkDx062nuNifVKtyaara3F30AIkKSEC
   MQDi29efbTLbdtDk3tecY/rD7V77XaJ6nYCmdDCR54TrSFNLgxvt1lyFM+0fYpYR
   c3o=
   -----END CERTIFICATE-----
   The registrar public certificate as decoded by openssl's x509
   utility.  Note that the registrar certificate is marked with the
   cmcRA extension.

   Certificate:
       Data:
           Version: 3 (0x2)
           Serial Number: 3 (0x3)
       Signature Algorithm: ecdsa-with-SHA384
           Issuer: DC = ca, DC = sandelman, CN = Unstrung Fount
   ain DC=ca, DC=sandelman, CN=Unstrung Fountain CA
           Validity
               Not Before: Sep  5 01:12:45 2017 GMT
               Not After : Sep  5 01:12:45 2019 GMT
           Subject: DC = ca, DC = sandelman, CN = localhost DC=ca, DC=sandelman, CN=localhost
           Subject Public Key Info:
               Public Key Algorithm: id-ecPublicKey
                   Public-Key: (256 bit)
                   pub:
                       04:35:64:0e:cd:c3:4c:52:33:f4:36:bb:5f:7
   8:17:
                       34:0c:92:d6:7d:e3:06:80:21:5d:22:fe:85:5
   3:3e:
                       03:89:f3:35:ba:33:01:79:cf:e0:e9:6f:cf:e
   9:ba:
                       13:9b:24:c6:74:53:a1:ff:c1:f0:29:47:ab:2
   f:96:
                       e9:9d:e2:bc:b2
                   ASN1 OID: prime256v1
                   NIST CURVE: P-256
           X509v3 extensions:
               X509v3 Basic Constraints:
                   CA:FALSE
       Signature Algorithm: ecdsa-with-SHA384
            30:66:02:31:00:b7:fe:24:d0:27:77:af:61:87:20:6d:78:
   5b:
            9b:3a:e9:eb:8b:77:40:2e:aa:8c:87:98:da:39:03:c7:4e:
   b6:
            9e:e3:62:7d:52:ad:c9:a6:ab:6b:71:77:d0:02:24:29:21:
   02:
            31:00:e2:db:d7:9f:6d:32:db:76:d0:e4:de:d7:9c:63:fa:
   c3:
            ed:5e:fb:5d:a2:7a:9d:80:a6:74:30:91:e7:84:eb:48:53:
   4b:
            83:1b:ed:d6:5c:85:33:ed:1f:62:96:11:73:7a

D.1.4.  Pledge key pair

   The pledge has an IDevID key pair built in at manufacturing time:

   -----BEGIN EC PRIVATE KEY-----
   MHcCAQEEIBgR6SV+uEvWfl5zCQWZxWjYbMhXPyNqdHJ3KPh11mm4oAoGCCqGSM49
   AwEHoUQDQgAEWi/jqPpRJ0JgWghZRgeZlLKutbXVjmnHb+1AYaEF/YQjE2g5FZV8
   KjiR/bkEl+l8M4onIC7KHaXKKkuag9S6Tw==
   -----END EC PRIVATE KEY-----

   The public key is used by the registrar to find the MASA.  The MASA
   URL is in an extension described in Section 2.3.

   -----BEGIN CERTIFICATE-----
   MIICBDCCAYugAwIBAgIECe20qTAKBggqhkjOPQQDAjBNMRIwEAYKCZImiZPyLGQB
   GRYCY2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xHDAaBgNVBAMME1Vuc3Ry
   dW5nIEhpZ2h3YXkgQ0EwIBcNMTkwNDI0MDIxNjU4WhgPMjk5OTEyMzEwMDAwMDBa
   MBwxGjAYBgNVBAUMETAwLWQwLWU1LTAyLTAwLTJkMFkwEwYHKoZIzj0CAQYIKoZI
   zj0DAQcDQgAEWi/jqPpRJ0JgWghZRgeZlLKutbXVjmnHb+1AYaEF/YQjE2g5FZV8
   KjiR/bkEl+l8M4onIC7KHaXKKkuag9S6T6OBhzCBhDAdBgNVHQ4EFgQUj8KYdUoE
   OvJ0kcOIbjEWwgWdDYkwCQYDVR0TBAIwADArBgNVHREEJDAioCAGCSsGAQQBgu5S
   AaATDBEwMC1EMC1FNS0wMi0wMC0yRDArBgkrBgEEAYLuUgIEHgwcbWFzYS5ob25l
   eWR1a2VzLnNhbmRlbG1hbi5jYTAKBggqhkjOPQQDAgNnADBkAjAmvMjmNgjypDhc
   fynMV3kMuIpSKrYzRWr4g3PtTwXDsAe0oitTTj4QtU1bajhOfTkCMGMNbsW2Q41F
   z9t6PDVdtOKabBbAP1RVoFTlDQuO9nmLzb5kU+cUqCtPRFZBUXP3kg==
   -----END CERTIFICATE-----

   The pledge public certificate as decoded by openssl's x509 utility so
   that the extensions can be seen.  There is a second Custom Extension
   is included to provided to contain the EUI48/EUI64 that the pledge
   will configure as it's layer-2 address (this is non-normative).

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 166573225 (0x9edb4a9)
        Signature Algorithm: ecdsa-with-SHA256
        Issuer: DC = ca, DC = sandelman, CN = Unstrung Highway CA
        Validity
            Not Before: Apr 24 02:16:58 2019 GMT
            Not After : Dec 31 00:00:00 2999 GMT
        Subject: serialNumber = 00-d0-e5-02-00-2d
        Subject Public Key Info:
            Public Key Algorithm: id-ecPublicKey
                Public-Key: (256 bit)
                pub:
                    04:5a:2f:e3:a8:fa:51:27:42:60:5a:08:59:46:07:
                    99:94:b2:ae:b5:b5:d5:8e:69:c7:6f:ed:40:61:a1:
                    05:fd:84:23:13:68:39:15:95:7c:2a:38:91:fd:b9:
                    04:97:e9:7c:33:8a:27:20:2e:ca:1d:a5:ca:2a:4b:
                    9a:83:d4:ba:4f
                ASN1 OID: prime256v1
                NIST CURVE: P-256
        X509v3 extensions:
            X509v3 Subject Key Identifier:
                8F:C2:98:75:4A:04:3A:F2:74:91:C3:88:6E:31:16:C2:05:9D:0D:89
            X509v3 Basic Constraints:
                CA:FALSE
            X509v3 Subject Alternative Name:
                othername:<unsupported>
            1.3.6.1.4.1.46930.2:
                ..masa.honeydukes.sandelman.ca
    Signature Algorithm: ecdsa-with-SHA256
         30:64:02:30:26:bc:c8:e6:36:08:f2:a4:38:5c:7f:29:cc:57:
         79:0c:b8:8a:52:2a:b6:33:45:6a:f8:83:73:ed:4f:05:c3:b0:
         07:b4:a2:2b:53:4e:3e:10:b5:4d:5b:6a:38:4e:7d:39:02:30:
         63:0d:6e:c5:b6:43:8d:45:cf:db:7a:3c:35:5d:b4:e2:9a:6c:
         16:c0:3f:54:55:a0:54:e5:0d:0b:8e:f6:79:8b:cd:be:64:53:
         e7:14:a8:2b:4f:44:56:41:51:73:f7:92

D.2.  Example process

   The JSON examples below are wrapped at 60 columns.  This results in
   strings that have newlines in them, which makes them invalid JSON as
   is.  The strings would otherwise be too long, so they need to be
   unwrapped before processing.

D.2.1.  Pledge to Registrar

   As described in Section 5.2, the pledge will sign a pledge voucher-
   request containing the registrar's public key in the proximity-
   registrar-cert field.  The base64 has been wrapped at 60 characters
   for presentation reasons.

   -----BEGIN CMS-----
   MIIGtQYJKoZIhvcNAQcCoIIGpjCCBqICAQExDTALBglghkgBZQMEAgEwggNRBgkq
   hkiG9w0BBwGgggNCBIIDPnsiaWV0Zi12b3VjaGVyLXJlcXVlc3Q6dm91Y2hlciI6
   eyJhc3NlcnRpb24iOiJwcm94aW1pdHkiLCJjcmVhdGVkLW9uIjoiMjAxOS0wNS0x
   NVQxNzoyNTo1NS42NDQtMDQ6MDAiLCJzZXJpYWwtbnVtYmVyIjoiMDAtZDAtZTUt
   MDItMDAtMmQiLCJub25jZSI6IlZPVUZULVd3ckV2ME51QVFFSG9WN1EiLCJwcm94
   aW1pdHktcmVnaXN0cmFyLWNlcnQiOiJNSUlCMFRDQ0FWYWdBd0lCQWdJQkFqQUtC
   Z2dxaGtqT1BRUURBekJ4TVJJd0VBWUtDWkltaVpQeUxHUUJHUllDWTJFeEdUQVhC
   Z29Ka2lhSmsvSXNaQUVaRmdsellXNWtaV3h0WVc0eFFEQStCZ05WQkFNTU55TThV
   M2x6ZEdWdFZtRnlhV0ZpYkdVNk1IZ3dNREF3TURBd05HWTVNVEZoTUQ0Z1ZXNXpk
   SEoxYm1jZ1JtOTFiblJoYVc0Z1EwRXdIaGNOTVRjeE1UQTNNak0wTlRJNFdoY05N
   VGt4TVRBM01qTTBOVEk0V2pCRE1SSXdFQVlLQ1pJbWlaUHlMR1FCR1JZQ1kyRXhH
   VEFYQmdvSmtpYUprL0lzWkFFWkZnbHpZVzVrWld4dFlXNHhFakFRQmdOVkJBTU1D
   V3h2WTJGc2FHOXpkREJaTUJNR0J5cUdTTTQ5QWdFR0NDcUdTTTQ5QXdFSEEwSUFC
   SlpsVUhJMHVwL2wzZVpmOXZDQmIrbElub0VNRWdjN1JvK1haQ3RqQUkwQ0QxZkpm
   SlIvaEl5eURtSFd5WWlORmJSQ0g5ZnlhcmZremdYNHAwelRpenFqRFRBTE1Ba0dB
   MVVkRXdRQ01BQXdDZ1lJS29aSXpqMEVBd01EYVFBd1pnSXhBTFFNTnVyZjh0djUw
   bFJPRDVEUVhIRU9KSk5XM1FWMmc5UUVkRFNrMk1ZK0FvU3JCU21HU05qaDRvbEVP
   aEV1TGdJeEFKNG5XZk53K0JqYlptS2lJaVVFY1R3SE1oR1ZYYU1IWS9GN24zOXd3
   S2NCQlNPbmROUHFDcE9FTGw2YnEzQ1pxUT09In19oIICCDCCAgQwggGLoAMCAQIC
   BAnttKkwCgYIKoZIzj0EAwIwTTESMBAGCgmSJomT8ixkARkWAmNhMRkwFwYKCZIm
   iZPyLGQBGRYJc2FuZGVsbWFuMRwwGgYDVQQDDBNVbnN0cnVuZyBIaWdod2F5IENB
   MCAXDTE5MDQyNDAyMTY1OFoYDzI5OTkxMjMxMDAwMDAwWjAcMRowGAYDVQQFDBEw
   MC1kMC1lNS0wMi0wMC0yZDBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABFov46j6
   USdCYFoIWUYHmZSyrrW11Y5px2/tQGGhBf2EIxNoORWVfCo4kf25BJfpfDOKJyAu
   yh2lyipLmoPUuk+jgYcwgYQwHQYDVR0OBBYEFI/CmHVKBDrydJHDiG4xFsIFnQ2J
   MAkGA1UdEwQCMAAwKwYDVR0RBCQwIqAgBgkrBgEEAYLuUgGgEwwRMDAtRDAtRTUt
   MDItMDAtMkQwKwYJKwYBBAGC7lICBB4MHG1hc2EuaG9uZXlkdWtlcy5zYW5kZWxt
   YW4uY2EwCgYIKoZIzj0EAwIDZwAwZAIwJrzI5jYI8qQ4XH8pzFd5DLiKUiq2M0Vq
   +INz7U8Fw7AHtKIrU04+ELVNW2o4Tn05AjBjDW7FtkONRc/bejw1XbTimmwWwD9U
   VaBU5Q0LjvZ5i82+ZFPnFKgrT0RWQVFz95IxggErMIIBJwIBATBVME0xEjAQBgoJ
   kiaJk/IsZAEZFgJjYTEZMBcGCgmSJomT8ixkARkWCXNhbmRlbG1hbjEcMBoGA1UE
   AwwTVW5zdHJ1bmcgSGlnaHdheSBDQQIECe20qTALBglghkgBZQMEAgGgaTAYBgkq
   hkiG9w0BCQMxCwYJKoZIhvcNAQcBMBwGCSqGSIb3DQEJBTEPFw0xOTA1MTUyMTI1
   NTVaMC8GCSqGSIb3DQEJBDEiBCAQN2lP7aqwyhmj9qUHt6Qk/SbOTOPXFOwn1wv2
   5YGYgDAKBggqhkjOPQQDAgRHMEUCIEYQhHToU0rrhPyQv2fR0TwWePTx2Z1DEhR4
   tTl/Dr/ZAiEA47u9+bIz/p6nFJ+wctKHER+ycUzYQF56h9odMo+Ilkc=
   -----END CMS-----

   file: examples/vr_00-D0-E5-02-00-2D.pkcs
   The ASN1 decoding of the artifact:

    0:d=0  hl=4 l=1717 cons: SEQUENCE
    4:d=1  hl=2 l=   9 prim: OBJECT            :pkcs7-signedData
   15:d=1  hl=4 l=1702 cons: cont [ 0 ]
   19:d=2  hl=4 l=1698 cons: SEQUENCE
   23:d=3  hl=2 l=   1 prim: INTEGER           :01
   26:d=3  hl=2 l=  13 cons: SET
   28:d=4  hl=2 l=  11 cons: SEQUENCE
   30:d=5  hl=2 l=   9 prim: OBJECT            :sha256
   41:d=3  hl=4 l= 849 cons: SEQUENCE
   45:d=4  hl=2 l=   9 prim: OBJECT            :pkcs7-data
   56:d=4  hl=4 l= 834 cons: cont [ 0 ]
   60:d=5  hl=4 l= 830 prim: OCTET STRING      :{"ietf-voucher-request:v
  894:d=3  hl=4 l= 520 cons: cont [ 0 ]
  898:d=4  hl=4 l= 516 cons: SEQUENCE
  902:d=5  hl=4 l= 395 cons: SEQUENCE
  906:d=6  hl=2 l=   3 cons: cont [ 0 ]
  908:d=7  hl=2 l=   1 prim: INTEGER           :02
  911:d=6  hl=2 l=   4 prim: INTEGER           :09EDB4A9
  917:d=6  hl=2 l=  10 cons: SEQUENCE
  919:d=7  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
  929:d=6  hl=2 l=  77 cons: SEQUENCE
  931:d=7  hl=2 l=  18 cons: SET
  933:d=8  hl=2 l=  16 cons: SEQUENCE
  935:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
  947:d=9  hl=2 l=   2 prim: IA5STRING         :ca
  951:d=7  hl=2 l=  25 cons: SET
  953:d=8  hl=2 l=  23 cons: SEQUENCE
  955:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
  967:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
  978:d=7  hl=2 l=  28 cons: SET
  980:d=8  hl=2 l=  26 cons: SEQUENCE
  982:d=9  hl=2 l=   3 prim: OBJECT            :commonName
  987:d=9  hl=2 l=  19 prim: UTF8STRING        :Unstrung Highway CA
 1008:d=6  hl=2 l=  32 cons: SEQUENCE
 1010:d=7  hl=2 l=  13 prim: UTCTIME           :190424021658Z
 1025:d=7  hl=2 l=  15 prim: GENERALIZEDTIME   :29991231000000Z
 1042:d=6  hl=2 l=  28 cons: SEQUENCE
 1044:d=7  hl=2 l=  26 cons: SET
 1046:d=8  hl=2 l=  24 cons: SEQUENCE
 1048:d=9  hl=2 l=   3 prim: OBJECT            :serialNumber
 1053:d=9  hl=2 l=  17 prim: UTF8STRING        :00-d0-e5-02-00-2d
 1072:d=6  hl=2 l=  89 cons: SEQUENCE
 1074:d=7  hl=2 l=  19 cons: SEQUENCE
 1076:d=8  hl=2 l=   7 prim: OBJECT            :id-ecPublicKey
 1085:d=8  hl=2 l=   8 prim: OBJECT            :prime256v1
 1095:d=7  hl=2 l=  66 prim: BIT STRING
 1163:d=6  hl=3 l= 135 cons: cont [ 3 ]
 1166:d=7  hl=3 l= 132 cons: SEQUENCE
 1169:d=8  hl=2 l=  29 cons: SEQUENCE
 1171:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Subject Key Ident
 1176:d=9  hl=2 l=  22 prim: OCTET STRING      [HEX DUMP]:04148FC298754A
 1200:d=8  hl=2 l=   9 cons: SEQUENCE
 1202:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Basic Constraints
 1207:d=9  hl=2 l=   2 prim: OCTET STRING      [HEX DUMP]:3000
 1211:d=8  hl=2 l=  43 cons: SEQUENCE
 1213:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Subject Alternati
 1218:d=9  hl=2 l=  36 prim: OCTET STRING      [HEX DUMP]:3022A02006092B
 1256:d=8  hl=2 l=  43 cons: SEQUENCE
 1258:d=9  hl=2 l=   9 prim: OBJECT            :1.3.6.1.4.1.46930.2
 1269:d=9  hl=2 l=  30 prim: OCTET STRING      [HEX DUMP]:0C1C6D6173612E
 1301:d=5  hl=2 l=  10 cons: SEQUENCE
 1303:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
 1313:d=5  hl=2 l= 103 prim: BIT STRING
 1418:d=3  hl=4 l= 299 cons: SET
 1422:d=4  hl=4 l= 295 cons: SEQUENCE
 1426:d=5  hl=2 l=   1 prim: INTEGER           :01
 1429:d=5  hl=2 l=  85 cons: SEQUENCE
 1431:d=6  hl=2 l=  77 cons: SEQUENCE
 1433:d=7  hl=2 l=  18 cons: SET
 1435:d=8  hl=2 l=  16 cons: SEQUENCE
 1437:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 1449:d=9  hl=2 l=   2 prim: IA5STRING         :ca
 1453:d=7  hl=2 l=  25 cons: SET
 1455:d=8  hl=2 l=  23 cons: SEQUENCE
 1457:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 1469:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
 1480:d=7  hl=2 l=  28 cons: SET
 1482:d=8  hl=2 l=  26 cons: SEQUENCE
 1484:d=9  hl=2 l=   3 prim: OBJECT            :commonName
 1489:d=9  hl=2 l=  19 prim: UTF8STRING        :Unstrung Highway CA
 1510:d=6  hl=2 l=   4 prim: INTEGER           :09EDB4A9
 1516:d=5  hl=2 l=  11 cons: SEQUENCE
 1518:d=6  hl=2 l=   9 prim: OBJECT            :sha256
 1529:d=5  hl=2 l= 105 cons: cont [ 0 ]
 1531:d=6  hl=2 l=  24 cons: SEQUENCE
 1533:d=7  hl=2 l=   9 prim: OBJECT            :contentType
 1544:d=7  hl=2 l=  11 cons: SET
 1546:d=8  hl=2 l=   9 prim: OBJECT            :pkcs7-data
 1557:d=6  hl=2 l=  28 cons: SEQUENCE
 1559:d=7  hl=2 l=   9 prim: OBJECT            :signingTime
 1570:d=7  hl=2 l=  15 cons: SET
 1572:d=8  hl=2 l=  13 prim: UTCTIME           :190515212555Z
 1587:d=6  hl=2 l=  47 cons: SEQUENCE
 1589:d=7  hl=2 l=   9 prim: OBJECT            :messageDigest
 1600:d=7  hl=2 l=  34 cons: SET
 1602:d=8  hl=2 l=  32 prim: OCTET STRING      [HEX DUMP]:1037694FEDAAB0
 1636:d=5  hl=2 l=  10 cons: SEQUENCE
 1638:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
 1648:d=5  hl=2 l=  71 prim: OCTET STRING      [HEX DUMP]:30450220461084

   The JSON contained in the voucher request:

   {"ietf-voucher-request:voucher":{"assertion":"proximity","cr
   eated-on":"2019-05-15T17:25:55.644-04:00","serial-number":"0
   0-d0-e5-02-00-2d","nonce":"VOUFT-WwrEv0NuAQEHoV7Q","proximit
   y-registrar-cert":"MIIB0TCCAVagAwIBAgIBAjAKBggqhkjOPQQDAzBxM
   RIwEAYKCZImiZPyLGQBGRYCY2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtY
   W4xQDA+BgNVBAMMNyM8U3lzdGVtVmFyaWFibGU6MHgwMDAwMDAwNGY5MTFhM
   D4gVW5zdHJ1bmcgRm91bnRhaW4gQ0EwHhcNMTcxMTA3MjM0NTI4WhcNMTkxM
   TA3MjM0NTI4WjBDMRIwEAYKCZImiZPyLGQBGRYCY2ExGTAXBgoJkiaJk/IsZ
   AEZFglzYW5kZWxtYW4xEjAQBgNVBAMMCWxvY2FsaG9zdDBZMBMGByqGSM49A
   gEGCCqGSM49AwEHA0IABJZlUHI0up/l3eZf9vCBb+lInoEMEgc7Ro+XZCtjA
   I0CD1fJfJR/hIyyDmHWyYiNFbRCH9fyarfkzgX4p0zTizqjDTALMAkGA1UdE
   wQCMAAwCgYIKoZIzj0EAwMDaQAwZgIxALQMNurf8tv50lROD5DQXHEOJJNW3
   QV2g9QEdDSk2MY+AoSrBSmGSNjh4olEOhEuLgIxAJ4nWfNw+BjbZmKiIiUEc
   TwHMhGVXaMHY/F7n39wwKcBBSOndNPqCpOELl6bq3CZqQ=="}}

D.2.2.  Registrar to MASA

   As described in Section 5.5 the registrar will sign a registrar
   voucher-request, and will include pledge's voucher request in the
   prior-signed-voucher-request.

   -----BEGIN CMS-----
   MIIPkwYJKoZIhvcNAQcCoIIPhDCCD4ACAQExDTALBglghkgBZQMEAgEwggnUBgkq
   hkiG9w0BBwGgggnFBIIJwXsiaWV0Zi12b3VjaGVyLXJlcXVlc3Q6dm91Y2hlciI6
   eyJhc3NlcnRpb24iOiJwcm94aW1pdHkiLCJjcmVhdGVkLW9uIjoiMjAxOS0wNS0x
   NVQyMToyNTo1NS43NThaIiwic2VyaWFsLW51bWJlciI6IjAwLWQwLWU1LTAyLTAw
   LTJkIiwibm9uY2UiOiJWT1VGVC1Xd3JFdjBOdUFRRUhvVjdRIiwicHJpb3Itc2ln
   bmVkLXZvdWNoZXItcmVxdWVzdCI6Ik1JSUd0UVlKS29aSWh2Y05BUWNDb0lJR3Bq
   Q0NCcUlDQVFFeERUQUxCZ2xnaGtnQlpRTUVBZ0V3Z2dOUkJna3Foa2lHOXcwQkJ3
   R2dnZ05DQklJRFBuc2lhV1YwWmkxMmIzVmphR1Z5TFhKbGNYVmxjM1E2ZG05MVky
   aGxjaUk2ZXlKaGMzTmxjblJwYjI0aU9pSndjbTk0YVcxcGRIa2lMQ0pqY21WaGRH
   VmtMVzl1SWpvaU1qQXhPUzB3TlMweE5WUXhOem95TlRvMU5TNDJORFF0TURRNk1E
   QWlMQ0p6WlhKcFlXd3RiblZ0WW1WeUlqb2lNREF0WkRBdFpUVXRNREl0TURBdE1t
   UWlMQ0p1YjI1alpTSTZJbFpQVlVaVUxWZDNja1YyTUU1MVFWRkZTRzlXTjFFaUxD
   SndjbTk0YVcxcGRIa3RjbVZuYVhOMGNtRnlMV05sY25RaU9pSk5TVWxDTUZSRFEw
   RldZV2RCZDBsQ1FXZEpRa0ZxUVV0Q1oyZHhhR3RxVDFCUlVVUkJla0o0VFZKSmQw
   VkJXVXREV2tsdGFWcFFlVXhIVVVKSFVsbERXVEpGZUVkVVFWaENaMjlLYTJsaFNt
   c3ZTWE5hUVVWYVJtZHNlbGxYTld0YVYzaDBXVmMwZUZGRVFTdENaMDVXUWtGTlRV
   NTVUVGhWTTJ4NlpFZFdkRlp0Um5saFYwWnBZa2RWTmsxSVozZE5SRUYzVFVSQmQw
   NUhXVFZOVkVab1RVUTBaMVpYTlhwa1NFb3hZbTFqWjFKdE9URmlibEpvWVZjMFox
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   aElSVTlLU2s1WE0xRldNbWM1VVVWa1JGTnJNazFaSzBGdlUzSkNVMjFIVTA1cWFE
   UnZiRVZQYUVWMVRHZEplRUZLTkc1WFprNTNLMEpxWWxwdFMybEphVlZGWTFSM1NF
   MW9SMVpZWVUxSVdTOUdOMjR6T1hkM1MyTkNRbE5QYm1ST1VIRkRjRTlGVEd3Mllu
   RXpRMXB4VVQwOUluMTlvSUlDQ0RDQ0FnUXdnZ0dMb0FNQ0FRSUNCQW50dEtrd0Nn
   WUlLb1pJemowRUF3SXdUVEVTTUJBR0NnbVNKb21UOGl4a0FSa1dBbU5oTVJrd0Z3
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   b3Y0Nmo2VVNkQ1lGb0lXVVlIbVpTeXJyVzExWTVweDIvdFFHR2hCZjJFSXhOb09S
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   QXdaQUl3SnJ6STVqWUk4cVE0WEg4cHpGZDVETGlLVWlxMk0wVnErSU56N1U4Rnc3
   QUh0S0lyVTA0K0VMVk5XMm80VG4wNUFqQmpEVzdGdGtPTlJjL2JlancxWGJUaW1t
   d1d3RDlVVmFCVTVRMExqdlo1aTgyK1pGUG5GS2dyVDBSV1FWRno5NUl4Z2dFck1J
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   bVNKb21UOGl4a0FSa1dDWE5oYm1SbGJHMWhiakVjTUJvR0ExVUVBd3dUVlc1emRI
   SjFibWNnU0dsbmFIZGhlU0JEUVFJRUNlMjBxVEFMQmdsZ2hrZ0JaUU1FQWdHZ2FU
   QVlCZ2txaGtpRzl3MEJDUU14Q3dZSktvWklodmNOQVFjQk1Cd0dDU3FHU0liM0RR
   RUpCVEVQRncweE9UQTFNVFV5TVRJMU5UVmFNQzhHQ1NxR1NJYjNEUUVKQkRFaUJD
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   MURFaFI0dFRsL0RyL1pBaUVBNDd1OStiSXovcDZuRkord2N0S0hFUit5Y1V6WVFG
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   aQAwZgIxALQMNurf8tv50lROD5DQXHEOJJNW3QV2g9QEdDSk2MY+AoSrBSmGSNjh
   4olEOhEuLgIxAJ4nWfNw+BjbZmKiIiUEcTwHMhGVXaMHY/F7n39wwKcBBSOndNPq
   CpOELl6bq3CZqTCCAmkwggHvoAMCAQICAQMwCgYIKoZIzj0EAwIwbTESMBAGCgmS
   JomT8ixkARkWAmNhMRkwFwYKCZImiZPyLGQBGRYJc2FuZGVsbWFuMTwwOgYDVQQD
   DDNmb3VudGFpbi10ZXN0LmV4YW1wbGUuY29tIFVuc3RydW5nIEZvdW50YWluIFJv
   b3QgQ0EwHhcNMTkwMTEzMjI1NDQ0WhcNMjEwMTEyMjI1NDQ0WjBtMRIwEAYKCZIm
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   dCBDQTB2MBAGByqGSM49AgEGBSuBBAAiA2IABBt/WboXwxq8Zo2MbODD+jFxD2X2
   IpG9t1aAB9vfuHqlRU15ikaXGVmWMbGPaX0yvjzIPltjtUb2qNVvm/nA89O5FD9y
   R1Gkdt3S8L/1yo8wAX/4wl/T9SADRIuL8gdstKNjMGEwDwYDVR0TAQH/BAUwAwEB
   /zAOBgNVHQ8BAf8EBAMCAQYwHQYDVR0OBBYEFLml9ssR4QekSSynCMZ8ELyHs3Qm
   MB8GA1UdIwQYMBaAFLml9ssR4QekSSynCMZ8ELyHs3QmMAoGCCqGSM49BAMCA2gA
   MGUCMAviLdbfd6AZdsOxNgf7D15WFmGC1JkHeEbT/0w4UXz6q/48S71/IMbSXRWH
   aNxiJwIxAOCRjtlN+VSmCLTvWwMTxnSpIuqMr/O1y2Z8rl459VRFphWPdbf4i0qE
   cwu0u4JzpDGCAUwwggFIAgEBMHYwcTESMBAGCgmSJomT8ixkARkWAmNhMRkwFwYK
   CZImiZPyLGQBGRYJc2FuZGVsbWFuMUAwPgYDVQQDDDcjPFN5c3RlbVZhcmlhYmxl
   OjB4MDAwMDAwMDRmOTExYTA+IFVuc3RydW5nIEZvdW50YWluIENBAgECMAsGCWCG
   SAFlAwQCAaBpMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkF
   MQ8XDTE5MDUxNTIxMjU1NVowLwYJKoZIhvcNAQkEMSIEIFBQjMmWzZOEkRHXrVAS
   snJwgQ26goyvOAtUFYs3MstMMAoGCCqGSM49BAMCBEcwRQIgBthbhEmgbqZbYDkD
   zxHXLzJ5eusWplzHKqZyxNpzaR8CIQC3UtMu0QsXoUpYL016iTsbd7Eedi8IfnwQ
   akExfhh0ew==
   -----END CMS-----

   file: examples/parboiled_vr_00_D0-E5-02-00-2D.pkcs

   The ASN1 decoding of the artifact:

    0:d=0  hl=4 l=3987 cons: SEQUENCE
    4:d=1  hl=2 l=   9 prim: OBJECT            :pkcs7-signedData
   15:d=1  hl=4 l=3972 cons: cont [ 0 ]
   19:d=2  hl=4 l=3968 cons: SEQUENCE
   23:d=3  hl=2 l=   1 prim: INTEGER           :01
   26:d=3  hl=2 l=  13 cons: SET
   28:d=4  hl=2 l=  11 cons: SEQUENCE
   30:d=5  hl=2 l=   9 prim: OBJECT            :sha256
   41:d=3  hl=4 l=2516 cons: SEQUENCE
   45:d=4  hl=2 l=   9 prim: OBJECT            :pkcs7-data
   56:d=4  hl=4 l=2501 cons: cont [ 0 ]
   60:d=5  hl=4 l=2497 prim: OCTET STRING      :{"ietf-voucher-request:v
 2561:d=3  hl=4 l=1090 cons: cont [ 0 ]
 2565:d=4  hl=4 l= 465 cons: SEQUENCE
 2569:d=5  hl=4 l= 342 cons: SEQUENCE
 2573:d=6  hl=2 l=   3 cons: cont [ 0 ]
 2575:d=7  hl=2 l=   1 prim: INTEGER           :02
 2578:d=6  hl=2 l=   1 prim: INTEGER           :02
 2581:d=6  hl=2 l=  10 cons: SEQUENCE
 2583:d=7  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA384
 2593:d=6  hl=2 l= 113 cons: SEQUENCE
 2595:d=7  hl=2 l=  18 cons: SET
 2597:d=8  hl=2 l=  16 cons: SEQUENCE
 2599:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 2611:d=9  hl=2 l=   2 prim: IA5STRING         :ca
 2615:d=7  hl=2 l=  25 cons: SET
 2617:d=8  hl=2 l=  23 cons: SEQUENCE
 2619:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 2631:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
 2642:d=7  hl=2 l=  64 cons: SET
 2644:d=8  hl=2 l=  62 cons: SEQUENCE
 2646:d=9  hl=2 l=   3 prim: OBJECT            :commonName
 2651:d=9  hl=2 l=  55 prim: UTF8STRING        :#<SystemVariable:0x00000
 2708:d=6  hl=2 l=  30 cons: SEQUENCE
 2710:d=7  hl=2 l=  13 prim: UTCTIME           :171107234528Z
 2725:d=7  hl=2 l=  13 prim: UTCTIME           :191107234528Z
 2740:d=6  hl=2 l=  67 cons: SEQUENCE
 2742:d=7  hl=2 l=  18 cons: SET
 2744:d=8  hl=2 l=  16 cons: SEQUENCE
 2746:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 2758:d=9  hl=2 l=   2 prim: IA5STRING         :ca
 2762:d=7  hl=2 l=  25 cons: SET
 2764:d=8  hl=2 l=  23 cons: SEQUENCE
 2766:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 2778:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
 2789:d=7  hl=2 l=  18 cons: SET
 2791:d=8  hl=2 l=  16 cons: SEQUENCE
 2793:d=9  hl=2 l=   3 prim: OBJECT            :commonName
 2798:d=9  hl=2 l=   9 prim: UTF8STRING        :localhost
 2809:d=6  hl=2 l=  89 cons: SEQUENCE
 2811:d=7  hl=2 l=  19 cons: SEQUENCE
 2813:d=8  hl=2 l=   7 prim: OBJECT            :id-ecPublicKey
 2822:d=8  hl=2 l=   8 prim: OBJECT            :prime256v1
 2832:d=7  hl=2 l=  66 prim: BIT STRING
 2900:d=6  hl=2 l=  13 cons: cont [ 3 ]
 2902:d=7  hl=2 l=  11 cons: SEQUENCE
 2904:d=8  hl=2 l=   9 cons: SEQUENCE
 2906:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Basic Constraints
 2911:d=9  hl=2 l=   2 prim: OCTET STRING      [HEX DUMP]:3000
 2915:d=5  hl=2 l=  10 cons: SEQUENCE
 2917:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA384
 2927:d=5  hl=2 l= 105 prim: BIT STRING
 3034:d=4  hl=4 l= 617 cons: SEQUENCE
 3038:d=5  hl=4 l= 495 cons: SEQUENCE
 3042:d=6  hl=2 l=   3 cons: cont [ 0 ]
 3044:d=7  hl=2 l=   1 prim: INTEGER           :02
 3047:d=6  hl=2 l=   1 prim: INTEGER           :03
 3050:d=6  hl=2 l=  10 cons: SEQUENCE
 3052:d=7  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
 3062:d=6  hl=2 l= 109 cons: SEQUENCE
 3064:d=7  hl=2 l=  18 cons: SET
 3066:d=8  hl=2 l=  16 cons: SEQUENCE
 3068:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 3080:d=9  hl=2 l=   2 prim: IA5STRING         :ca
 3084:d=7  hl=2 l=  25 cons: SET
 3086:d=8  hl=2 l=  23 cons: SEQUENCE
 3088:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 3100:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
 3111:d=7  hl=2 l=  60 cons: SET
 3113:d=8  hl=2 l=  58 cons: SEQUENCE
 3115:d=9  hl=2 l=   3 prim: OBJECT            :commonName
 3120:d=9  hl=2 l=  51 prim: UTF8STRING        :fountain-test.example.co
 3173:d=6  hl=2 l=  30 cons: SEQUENCE
 3175:d=7  hl=2 l=  13 prim: UTCTIME           :190113225444Z
 3190:d=7  hl=2 l=  13 prim: UTCTIME           :210112225444Z
 3205:d=6  hl=2 l= 109 cons: SEQUENCE
 3207:d=7  hl=2 l=  18 cons: SET
 3209:d=8  hl=2 l=  16 cons: SEQUENCE
 3211:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 3223:d=9  hl=2 l=   2 prim: IA5STRING         :ca
 3227:d=7  hl=2 l=  25 cons: SET
 3229:d=8  hl=2 l=  23 cons: SEQUENCE
 3231:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 3243:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
 3254:d=7  hl=2 l=  60 cons: SET
 3256:d=8  hl=2 l=  58 cons: SEQUENCE
 3258:d=9  hl=2 l=   3 prim: OBJECT            :commonName
 3263:d=9  hl=2 l=  51 prim: UTF8STRING        :fountain-test.example.co
 3316:d=6  hl=2 l= 118 cons: SEQUENCE
 3318:d=7  hl=2 l=  16 cons: SEQUENCE
 3320:d=8  hl=2 l=   7 prim: OBJECT            :id-ecPublicKey
 3329:d=8  hl=2 l=   5 prim: OBJECT            :secp384r1
 3336:d=7  hl=2 l=  98 prim: BIT STRING
 3436:d=6  hl=2 l=  99 cons: cont [ 3 ]
 3438:d=7  hl=2 l=  97 cons: SEQUENCE
 3440:d=8  hl=2 l=  15 cons: SEQUENCE
 3442:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Basic Constraints
 3447:d=9  hl=2 l=   1 prim: BOOLEAN           :255
 3450:d=9  hl=2 l=   5 prim: OCTET STRING      [HEX DUMP]:30030101FF
 3457:d=8  hl=2 l=  14 cons: SEQUENCE
 3459:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Key Usage
 3464:d=9  hl=2 l=   1 prim: BOOLEAN           :255
 3467:d=9  hl=2 l=   4 prim: OCTET STRING      [HEX DUMP]:03020106
 3473:d=8  hl=2 l=  29 cons: SEQUENCE
 3475:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Subject Key Ident
 3480:d=9  hl=2 l=  22 prim: OCTET STRING      [HEX DUMP]:0414B9A5F6CB11
 3504:d=8  hl=2 l=  31 cons: SEQUENCE
 3506:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Authority Key Ide
 3511:d=9  hl=2 l=  24 prim: OCTET STRING      [HEX DUMP]:30168014B9A5F6
 3537:d=5  hl=2 l=  10 cons: SEQUENCE
 3539:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
 3549:d=5  hl=2 l= 104 prim: BIT STRING
 3655:d=3  hl=4 l= 332 cons: SET
 3659:d=4  hl=4 l= 328 cons: SEQUENCE
 3663:d=5  hl=2 l=   1 prim: INTEGER           :01
 3666:d=5  hl=2 l= 118 cons: SEQUENCE
 3668:d=6  hl=2 l= 113 cons: SEQUENCE
 3670:d=7  hl=2 l=  18 cons: SET
 3672:d=8  hl=2 l=  16 cons: SEQUENCE
 3674:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 3686:d=9  hl=2 l=   2 prim: IA5STRING         :ca
 3690:d=7  hl=2 l=  25 cons: SET
 3692:d=8  hl=2 l=  23 cons: SEQUENCE
 3694:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 3706:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
 3717:d=7  hl=2 l=  64 cons: SET
 3719:d=8  hl=2 l=  62 cons: SEQUENCE
 3721:d=9  hl=2 l=   3 prim: OBJECT            :commonName
 3726:d=9  hl=2 l=  55 prim: UTF8STRING        :#<SystemVariable:0x00000
 3783:d=6  hl=2 l=   1 prim: INTEGER           :02
 3786:d=5  hl=2 l=  11 cons: SEQUENCE
 3788:d=6  hl=2 l=   9 prim: OBJECT            :sha256
 3799:d=5  hl=2 l= 105 cons: cont [ 0 ]
 3801:d=6  hl=2 l=  24 cons: SEQUENCE
 3803:d=7  hl=2 l=   9 prim: OBJECT            :contentType
 3814:d=7  hl=2 l=  11 cons: SET
 3816:d=8  hl=2 l=   9 prim: OBJECT            :pkcs7-data
 3827:d=6  hl=2 l=  28 cons: SEQUENCE
 3829:d=7  hl=2 l=   9 prim: OBJECT            :signingTime
 3840:d=7  hl=2 l=  15 cons: SET
 3842:d=8  hl=2 l=  13 prim: UTCTIME           :190515212555Z
 3857:d=6  hl=2 l=  47 cons: SEQUENCE
 3859:d=7  hl=2 l=   9 prim: OBJECT            :messageDigest
 3870:d=7  hl=2 l=  34 cons: SET
 3872:d=8  hl=2 l=  32 prim: OCTET STRING      [HEX DUMP]:50508CC996CD93
 3906:d=5  hl=2 l=  10 cons: SEQUENCE
 3908:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
 3918:d=5  hl=2 l=  71 prim: OCTET STRING      [HEX DUMP]:3045022006D85B

D.2.3.  MASA to Registrar

   The MASA will return a voucher to the registrar, to be relayed to the
   pledge.

   -----BEGIN CMS-----
   MIIGsgYJKoZIhvcNAQcCoIIGozCCBp8CAQExDTALBglghkgBZQMEAgEwggNABgkq
   hkiG9w0BBwGgggMxBIIDLXsiaWV0Zi12b3VjaGVyOnZvdWNoZXIiOnsiYXNzZXJ0
   aW9uIjoibG9nZ2VkIiwiY3JlYXRlZC1vbiI6IjIwMTktMDUtMTZUMDI6NTE6NDIu
   Njk3KzAwOjAwIiwic2VyaWFsLW51bWJlciI6IjAwLWQwLWU1LTAyLTAwLTJkIiwi
   bm9uY2UiOiJHWmUtT2pvZXJwS0VNNFNNN1N6UzlnIiwicGlubmVkLWRvbWFpbi1j
   ZXJ0IjoiTUlJQjBUQ0NBVmFnQXdJQkFnSUJBakFLQmdncWhrak9QUVFEQXpCeE1S
   SXdFQVlLQ1pJbWlaUHlMR1FCR1JZQ1kyRXhHVEFYQmdvSmtpYUprL0lzWkFFWkZn
   bHpZVzVrWld4dFlXNHhRREErQmdOVkJBTU1OeU04VTNsemRHVnRWbUZ5YVdGaWJH
   VTZNSGd3TURBd01EQXdOR1k1TVRGaE1ENGdWVzV6ZEhKMWJtY2dSbTkxYm5SaGFX
   NGdRMEV3SGhjTk1UY3hNVEEzTWpNME5USTRXaGNOTVRreE1UQTNNak0wTlRJNFdq
   QkRNUkl3RUFZS0NaSW1pWlB5TEdRQkdSWUNZMkV4R1RBWEJnb0praWFKay9Jc1pB
   RVpGZ2x6WVc1a1pXeHRZVzR4RWpBUUJnTlZCQU1NQ1d4dlkyRnNhRzl6ZERCWk1C
   TUdCeXFHU000OUFnRUdDQ3FHU000OUF3RUhBMElBQkpabFVISTB1cC9sM2VaZjl2
   Q0JiK2xJbm9FTUVnYzdSbytYWkN0akFJMENEMWZKZkpSL2hJeXlEbUhXeVlpTkZi
   UkNIOWZ5YXJma3pnWDRwMHpUaXpxakRUQUxNQWtHQTFVZEV3UUNNQUF3Q2dZSUtv
   Wkl6ajBFQXdNRGFRQXdaZ0l4QUxRTU51cmY4dHY1MGxST0Q1RFFYSEVPSkpOVzNR
   VjJnOVFFZERTazJNWStBb1NyQlNtR1NOamg0b2xFT2hFdUxnSXhBSjRuV2ZOdytC
   amJabUtpSWlVRWNUd0hNaEdWWGFNSFkvRjduMzl3d0tjQkJTT25kTlBxQ3BPRUxs
   NmJxM0NacVE9PSJ9faCCAfUwggHxMIIBeKADAgECAgQjzIkTMAoGCCqGSM49BAMC
   ME0xEjAQBgoJkiaJk/IsZAEZFgJjYTEZMBcGCgmSJomT8ixkARkWCXNhbmRlbG1h
   bjEcMBoGA1UEAwwTVW5zdHJ1bmcgSGlnaHdheSBDQTAeFw0xOTA0MjMyMzIxMDda
   Fw0xOTA1MjQwOTIxMDdaMGYxDzANBgNVBAYTBkNhbmFkYTESMBAGA1UECgwJU2Fu
   ZGVsbWFuMRMwEQYDVQQLDApob25leWR1a2VzMSowKAYDVQQDDCFtYXNhLmhvbmV5
   ZHVrZXMuc2FuZGVsbWFuLmNhIE1BU0EwdjAQBgcqhkjOPQIBBgUrgQQAIgNiAAQ1
   /2UdVp8zVmgADoBNql7LcPlJsEaaVAogYEqABikNOkoTO3oPjIQfNBxtGfRFzBXx
   gihzkTH58r8SW1L/Mej8AFqhB4SZyyjmWURdzD71Ju0M+tRritWf7T+QGaE+fcWj
   EDAOMAwGA1UdEwEB/wQCMAAwCgYIKoZIzj0EAwIDZwAwZAIwOMlNOMNYEZo4yLW4
   iRltDL8uirmjMdtVmmVYzqYHSindjP0a3pXQkQZ5LLARoSRWAjBTxsnv6ya5HpZI
   IWcspDPZGlOSDPm7nuRJSDkgWqevxLI4+9nmIhsfMBsDvz1DJhAxggFMMIIBSAIB
   ATBVME0xEjAQBgoJkiaJk/IsZAEZFgJjYTEZMBcGCgmSJomT8ixkARkWCXNhbmRl
   bG1hbjEcMBoGA1UEAwwTVW5zdHJ1bmcgSGlnaHdheSBDQQIEI8yJEzALBglghkgB
   ZQMEAgGgaTAYBgkqhkiG9w0BCQMxCwYJKoZIhvcNAQcBMBwGCSqGSIb3DQEJBTEP
   Fw0xOTA1MTYwMjUxNDJaMC8GCSqGSIb3DQEJBDEiBCCYRh4i21QjEjEk8leRLSVA
   x/EVY5g1bM40QM21oR4c2DAKBggqhkjOPQQDAgRoMGYCMQCYYOiSbIlED4nAN0iL
   e4S8ixWAZ9SXpGv77bB/G4fTTVTN35mnAeYBfeNfhC6/kOECMQDqlkCmwQJQDdEL
   asj1ISinJ/FnZjjgOMz9MXOmGNGIfw9v2VBb9mVyhsOSMcqlVig=
   -----END CMS-----

   file: examples/voucher_00-D0-E5-02-00-2D.pkcs

   The ASN1 decoding of the artifact:

    0:d=0  hl=4 l=1714 cons: SEQUENCE
    4:d=1  hl=2 l=   9 prim: OBJECT            :pkcs7-signedData
   15:d=1  hl=4 l=1699 cons: cont [ 0 ]
   19:d=2  hl=4 l=1695 cons: SEQUENCE
   23:d=3  hl=2 l=   1 prim: INTEGER           :01
   26:d=3  hl=2 l=  13 cons: SET
   28:d=4  hl=2 l=  11 cons: SEQUENCE
   30:d=5  hl=2 l=   9 prim: OBJECT            :sha256
   41:d=3  hl=4 l= 832 cons: SEQUENCE
   45:d=4  hl=2 l=   9 prim: OBJECT            :pkcs7-data
   56:d=4  hl=4 l= 817 cons: cont [ 0 ]
   60:d=5  hl=4 l= 813 prim: OCTET STRING      :{"ietf-voucher:voucher":
  877:d=3  hl=4 l= 501 cons: cont [ 0 ]
  881:d=4  hl=4 l= 497 cons: SEQUENCE
  885:d=5  hl=4 l= 376 cons: SEQUENCE
  889:d=6  hl=2 l=   3 cons: cont [ 0 ]
  891:d=7  hl=2 l=   1 prim: INTEGER           :02
  894:d=6  hl=2 l=   4 prim: INTEGER           :23CC8913
  900:d=6  hl=2 l=  10 cons: SEQUENCE
  902:d=7  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
  912:d=6  hl=2 l=  77 cons: SEQUENCE
  914:d=7  hl=2 l=  18 cons: SET
  916:d=8  hl=2 l=  16 cons: SEQUENCE
  918:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
  930:d=9  hl=2 l=   2 prim: IA5STRING         :ca
  934:d=7  hl=2 l=  25 cons: SET
  936:d=8  hl=2 l=  23 cons: SEQUENCE
  938:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
  950:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
  961:d=7  hl=2 l=  28 cons: SET
  963:d=8  hl=2 l=  26 cons: SEQUENCE
  965:d=9  hl=2 l=   3 prim: OBJECT            :commonName
  970:d=9  hl=2 l=  19 prim: UTF8STRING        :Unstrung Highway CA
  991:d=6  hl=2 l=  30 cons: SEQUENCE
  993:d=7  hl=2 l=  13 prim: UTCTIME           :190423232107Z
 1008:d=7  hl=2 l=  13 prim: UTCTIME           :190524092107Z
 1023:d=6  hl=2 l= 102 cons: SEQUENCE
 1025:d=7  hl=2 l=  15 cons: SET
 1027:d=8  hl=2 l=  13 cons: SEQUENCE
 1029:d=9  hl=2 l=   3 prim: OBJECT            :countryName
 1034:d=9  hl=2 l=   6 prim: PRINTABLESTRING   :Canada
 1042:d=7  hl=2 l=  18 cons: SET
 1044:d=8  hl=2 l=  16 cons: SEQUENCE
 1046:d=9  hl=2 l=   3 prim: OBJECT            :organizationName
 1051:d=9  hl=2 l=   9 prim: UTF8STRING        :Sandelman
 1062:d=7  hl=2 l=  19 cons: SET
 1064:d=8  hl=2 l=  17 cons: SEQUENCE
 1066:d=9  hl=2 l=   3 prim: OBJECT            :organizationalUnitName
 1071:d=9  hl=2 l=  10 prim: UTF8STRING        :honeydukes
 1083:d=7  hl=2 l=  42 cons: SET
 1085:d=8  hl=2 l=  40 cons: SEQUENCE
 1087:d=9  hl=2 l=   3 prim: OBJECT            :commonName
 1092:d=9  hl=2 l=  33 prim: UTF8STRING        :masa.honeydukes.sandelma
 1127:d=6  hl=2 l= 118 cons: SEQUENCE
 1129:d=7  hl=2 l=  16 cons: SEQUENCE
 1131:d=8  hl=2 l=   7 prim: OBJECT            :id-ecPublicKey
 1140:d=8  hl=2 l=   5 prim: OBJECT            :secp384r1
 1147:d=7  hl=2 l=  98 prim: BIT STRING
 1247:d=6  hl=2 l=  16 cons: cont [ 3 ]
 1249:d=7  hl=2 l=  14 cons: SEQUENCE
 1251:d=8  hl=2 l=  12 cons: SEQUENCE
 1253:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Basic Constraints
 1258:d=9  hl=2 l=   1 prim: BOOLEAN           :255
 1261:d=9  hl=2 l=   2 prim: OCTET STRING      [HEX DUMP]:3000
 1265:d=5  hl=2 l=  10 cons: SEQUENCE
 1267:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
 1277:d=5  hl=2 l= 103 prim: BIT STRING
 1382:d=3  hl=4 l= 332 cons: SET
 1386:d=4  hl=4 l= 328 cons: SEQUENCE
 1390:d=5  hl=2 l=   1 prim: INTEGER           :01
 1393:d=5  hl=2 l=  85 cons: SEQUENCE
 1395:d=6  hl=2 l=  77 cons: SEQUENCE
 1397:d=7  hl=2 l=  18 cons: SET
 1399:d=8  hl=2 l=  16 cons: SEQUENCE
 1401:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 1413:d=9  hl=2 l=   2 prim: IA5STRING         :ca
 1417:d=7  hl=2 l=  25 cons: SET
 1419:d=8  hl=2 l=  23 cons: SEQUENCE
 1421:d=9  hl=2 l=  10 prim: OBJECT            :domainComponent
 1433:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
 1444:d=7  hl=2 l=  28 cons: SET
 1446:d=8  hl=2 l=  26 cons: SEQUENCE
 1448:d=9  hl=2 l=   3 prim: OBJECT            :commonName
 1453:d=9  hl=2 l=  19 prim: UTF8STRING        :Unstrung Highway CA
 1474:d=6  hl=2 l=   4 prim: INTEGER           :23CC8913
 1480:d=5  hl=2 l=  11 cons: SEQUENCE
 1482:d=6  hl=2 l=   9 prim: OBJECT            :sha256
 1493:d=5  hl=2 l= 105 cons: cont [ 0 ]
 1495:d=6  hl=2 l=  24 cons: SEQUENCE
 1497:d=7  hl=2 l=   9 prim: OBJECT            :contentType
 1508:d=7  hl=2 l=  11 cons: SET
 1510:d=8  hl=2 l=   9 prim: OBJECT            :pkcs7-data
 1521:d=6  hl=2 l=  28 cons: SEQUENCE
 1523:d=7  hl=2 l=   9 prim: OBJECT            :signingTime
 1534:d=7  hl=2 l=  15 cons: SET
 1536:d=8  hl=2 l=  13 prim: UTCTIME           :190516025142Z
 1551:d=6  hl=2 l=  47 cons: SEQUENCE
 1553:d=7  hl=2 l=   9 prim: OBJECT            :messageDigest
 1564:d=7  hl=2 l=  34 cons: SET
 1566:d=8  hl=2 l=  32 prim: OCTET STRING      [HEX DUMP]:98461E22DB5423
 1600:d=5  hl=2 l=  10 cons: SEQUENCE
 1602:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-SHA256
 1612:d=5  hl=2 l= 104 prim: OCTET STRING      [HEX DUMP]:30660231009860

Authors' Addresses

   Max Pritikin
   Cisco

   Email: pritikin@cisco.com

   Michael C. Richardson
   Sandelman Software Works

   Email: mcr+ietf@sandelman.ca
   URI:   http://www.sandelman.ca/

   Toerless Eckert
   Futurewei Technologies Inc.  USA
   2330 Central Expy
   Santa Clara  95050
   USA

   Email: ttef@cs.fau.de

   Michael H. Behringer

   Email: Michael.H.Behringer@gmail.com

   Kent Watsen
   Watsen Networks

   Email: kent+ietf@watsen.net