ANIMA WG                                                     M. Pritikin
Internet-Draft                                                     Cisco
Intended status: Standards Track                           M. Richardson
Expires: August 24, September 6, 2018                                           SSW
                                                            M. Behringer

                                                            S. Bjarnason
                                                          Arbor Networks
                                                               K. Watsen
                                                        Juniper Networks
                                                              2 20,
                                                           March 5, 2018

        Bootstrapping Remote Secure Key Infrastructures (BRSKI)
               draft-ietf-anima-bootstrapping-keyinfra-11
               draft-ietf-anima-bootstrapping-keyinfra-12

Abstract

   This document specifies automated bootstrapping of a remote secure
   key infrastructure (BRSKI) using manufacturer installed X.509
   certificate, 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 is complete when the cryptographic identity of the new
   key infrastructure is successfully deployed to the device but 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 August 24, September 6, 2018.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Other  Prior Bootstrapping Approaches  . . . . . . . . . . . . .   5
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   6
     1.3.  Scope of solution . . . . . . . . . . . . . . . . . . . .   8   9
       1.3.1.  Support enironment  . . . . . . . . . . . . . . . . .   9
       1.3.2.  Constrained enironments . . . . . . . . . . . . . . .   9
       1.3.3.  Network Access Controls . . . . . . . . . . . . . . .  10
     1.4.  Leveraging the new key infrastructure / next steps  . . .  10
     1.5.  Requirements for Autonomic Network Infrastructure (ANI)
           devices . . . . . . . . . . . . . . . . . . . . . . . . .  10  11
   2.  Architectural Overview  . . . . . . . . . . . . . . . . . . .  11
     2.1.  Behavior of a Pledge  . . . . . . . . . . . . . . . . . .  12  13
     2.2.  Secure Imprinting using Vouchers  . . . . . . . . . . . .  14
     2.3.  Initial Device Identifier . . . . . . . . . . . . . . . .  15
       2.3.1.  Identification of the Pledge  . . . . . . . . . . . .  15
       2.3.2.  MASA URI extension  . . . . . . . . . . . . . . . . .  16
     2.4.  Protocol Flow . . . . . . . . . . . . . . . . . . . . . .  16  17
       2.4.1.  Architectural component: Pledge . . . . . . . . . . .  18  19
       2.4.2.  Architectural component: Circuit Proxy  . . . . . . .  18  19
       2.4.3.  Architectural component: Domain Registrar . . . . . .  18  19
       2.4.4.  Architectural component: Manufacturer Service . . . .  18  19
       2.4.5.  Architectural component: Public Key Infrastructure
               (PKI) . . . . . . . . . . . . . . . . . . . . . . . .  19
     2.5.  Certificate Time Validation . . . . . . . . . . . . . . .  20
       2.5.1.  Lack of realtime clock  . . . . . . . . . . . . . . .  20
       2.5.2.  Infinite Lifetime of IDevID . . . . . . . . . .  18 . . .  20
     2.6.  Cloud Registrar . . . . . . . . . . . . . . . . . . . . .  19  21
     2.7.  Determining the MASA to contact . . . . . . . . . . . . .  20  21
   3.  Voucher-Request artifact  . . . . . . . . . . . . . . . . . .  20  22
     3.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .  20  22
     3.2.  Examples  . . . . . . . . . . . . . . . . . . . . . . . .  21  23
     3.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  23  25
   4.  Proxy  Proxying details (Pledge - Proxy - Registrar) . . . . . . . . . . . . . . . . . . . . . . . .  26  28
     4.1.  Pledge discovery of Proxy . . . . . . . . . . . . . . . .  27  29
       4.1.1.  Proxy GRASP announcements . . . . . . . . . . . . . .  28  30
     4.2.  CoAP connection to Registrar  . . . . . . . . . . . . . .  28  31
     4.3.  HTTPS Proxy connection to Registrar . . . . . . . . . . .  28
     4.4.  Proxy discovery of Registrar  . . . . . . . . . . . . . .  29  31
   5.  Protocol Details  . . . . . . . . . . . . . . . . . . . . . .  30  33
     5.1.  BRSKI-EST TLS establishment details . . . . . . . . . . .  32  35
     5.2.  Pledge Requests Voucher from the Registrar  . . . . . . .  32  35
     5.3.  BRSKI-MASA TLS establishment details  . . . . . . . . . .  34  36
     5.4.  Registrar Requests Voucher from MASA  . . . . . . . . . .  34  37
     5.5.  Voucher Response  . . . . . . . . . . . . . . . . . . . .  37  39
       5.5.1.  Completing authentication of Provisional TLS
               connection  . . . . . . . . . . . . . . . . . . . . .  38  41
     5.6.  Voucher Status Telemetry  . . . . . . . . . . . . . . . .  39  41
     5.7.  MASA authorization log Request  . . . . . . . . . . . . .  40  42
       5.7.1.  MASA authorization log Response . . . . . . . . . . .  41  43
     5.8.  EST Integration for PKI bootstrapping . . . . . . . . . .  42  45
       5.8.1.  EST Distribution of CA Certificates . . . . . . . . .  43  45
       5.8.2.  EST CSR Attributes  . . . . . . . . . . . . . . . . .  43  46
       5.8.3.  EST Client Certificate Request  . . . . . . . . . . .  44  47
       5.8.4.  Enrollment Status Telemetry . . . . . . . . . . . . .  44  47
       5.8.5.  EST over CoAP . . . . . . . . . . . . . . . . . . . .  45  48
   6.  Reduced security operational modes  . . . . . . . . . . . . .  45  48
     6.1.  Trust Model . . . . . . . . . . . . . . . . . . . . . . .  46  48
     6.2.  Pledge security reductions  . . . . . . . . . . . . . . .  46  49
     6.3.  Registrar security reductions . . . . . . . . . . . . . .  47  50
     6.4.  MASA security reductions  . . . . . . . . . . . . . . . .  48  50
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  49  51
     7.1.  PKIX Registry . . . . . . . . . . . . . . . . . . . . . .  49  51
     7.2.  Voucher Status Telemetry  . . . . . . . . . . . . . . . .  49  52
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  49  52
     8.1.  Freshness in Voucher-Requests . . . . . . . . . . . . . .  51  54
     8.2.  Trusting manufacturers  . . . . . . . . . . . . . . . . .  55
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  52  56
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  52  56
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  52  56
     10.2.  Informative References . . . . . . . . . . . . . . . . .  55  59
   Appendix A.  IPv4 operations  . . . . . . . . . . . . . . . . . .  56  61
     A.1.  IPv4 Link Local addresses . . . . . . . . . . . . . . . .  57  61
     A.2.  Use of DHCPv4 . . . . . . . . . . . . . . . . . . . . . .  57  61
   Appendix B.  mDNS / DNSSD proxy discovery options . . . . . . . .  57  61
   Appendix C.  IPIP Join Proxy mechanism  . . . . . . . . . . . . .  58  62
     C.1.  Multiple Join networks on the Join Proxy side . . . . . .  58  62
     C.2.  Automatic configuration of tunnels on Registrar . . . . .  59  63
     C.3.  Proxy Neighbor Discovery by Join Proxy  . . . . . . . . .  59  63
     C.4.  Use of connected sockets; or IP_PKTINFO for CoAP on
           Registrar . . . . . . . . . . . . . . . . . . . . . . . .  60  64

     C.5.  Use of socket extension rather than virtual interface . .  60  64
   Appendix D.  MUD Extension  . . . . . . . . . . . . . . . . . . .  60  64
   Appendix E.  Example Vouchers . . . . . . . . . . . . . . . . . .  62  66
     E.1.  Keys involved . . . . . . . . . . . . . . . . . . . . . .  62  66
       E.1.1.  MASA key pair for voucher signatures  . . . . . . . .  62  66
       E.1.2.  Manufacturer key pair for IDevID signatures . . . . .  62  66
       E.1.3.  Registrar key pair  . . . . . . . . . . . . . . . . .  63  67
       E.1.4.  Pledge key pair . . . . . . . . . . . . . . . . . . .  65  69
     E.2.  Example process . . . . . . . . . . . . . . . . . . . . .  66  70
       E.2.1.  Pledge to Registrar . . . . . . . . . . . . . . . . .  66  70
       E.2.2.  Registrar to MASA . . . . . . . . . . . . . . . . . .  72  76
       E.2.3.  MASA to Registrar . . . . . . . . . . . . . . . . . .  78  82
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  83  87

1.  Introduction

   BRSKI provides a foundation solution for secure zero-touch (automated) bootstrap
   of virgin (untouched) devices that are called Pledges in this
   document.  These Pledges need to securely answer the following
   questions between discover (or be discovered by) an
   element of the network domain to which the Pledge belongs to perform
   the bootstrap.  This element (device) is called the
   "Registrar" and an unconfigured (Domain Join)
   Registrar.  Before any other operation, Pledge and untouched device called a
   "Pledge":

   o Registrar need to
   establish mutual trust:

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

   o

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

   o

   3.  Pledge authenticating the Registrar/Domain: "What is this
       domain's identity?"

   o

   4.  Pledge authorizing the Registrar: "Should I join it?"

   This document details protocols and messages to the endpoints to answer the above
   questions.  The Registrar actions derive from Pledge
   identity, third party cloud service communications,  It uses a TLS connection and local access
   control lists.  The an PKIX (X.509v3)
   certificate (an IEEE 802.1AR [IDevID] LDevID) of the Pledge actions derive from to answer
   points 1 and 2.  It uses a new artifact called a cryptographically
   protected "voucher" message delivered through that the Registrar but
   originating at
   registrar receives from a Manufacturer "Manufacturer Authorized Signing Authority. Authority"
   and passes to the Pledge to answer points 3 and 2.

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

   The syntactic details of vouchers are described in detail in
   [I-D.ietf-anima-voucher].  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 [I-D.ietf-anima-voucher].

   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.  Other  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 is has been to try and minimize user actions
   during
   bootstrapping. bootstrapping, but not eliminate all user-actions.  The enrollment protocol
   original EST protocol [RFC7030] details a set
   of non-autonomic bootstrapping methods in this vein: 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 database (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
   transfered to the Pledge.  This creates serveral 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
   [RFC2119].

   The following terms are defined for clarity:

   domainID:  The domain IDentity is the 160-bit SHA-1 hash of the BIT
      STRING of the subjectPublicKey of the root certificate for the
      Registrars in the domain.  This is consistent with the subject key
      identifier (Section 4.2.1.2 [RFC5280]).

   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 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
      [I-D.ietf-anima-voucher]

   Domain:  The set of entities that trust a common key infrastructure
      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 stores
      the trust anchor 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".  The term JRC is used in common with other bootstrap
      mechanisms.

   (Public) Key Infrastructure:  The collection of systems and processes
      that sustain the activities of a public key system.  In an ANIMA
      Autonomic system, this includes a Domain Certification Authority
      (CA), (Join) Registrar which acts as an [RFC5280] Registrar, as
      well as appropriate certificate revocation list (CRL) distribution
      points and/or OCSP ([RFC6960]) servers.

   Join Proxy:  A domain entity that helps the Pledge join the domain.
      A 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.  The Pledge is
      unaware that they are communicating with a Proxy rather than
      directly with a Registrar.

   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.

   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 [I-D.ietf-anima-voucher]

   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-autonomic-control-plane].  This document details
      specific requirements for pledges, proxies and registrars when
      they are part of an ANI.

1.3.  Scope of solution

   Questions have been posed as to whether this

1.3.1.  Support enironment

   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+) 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).

   In many target applications, the systems involved are (BRSKI) can support large router platforms with multi-gigabit multi-
   gigabit inter-connections, mounted in controlled access data centers.
   But this solution is not exclusive to the
   large, 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 the 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 aquire 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 protocol
   is usually called handoff.  BRSKI does not intended for low latency handoffs.  In networks
   requiring provide a low-latency
   handoff which is usually a requirement in such things, situations.  For these
   solutions BRSKI can be used to create a relationship (an LDevID) with
   the Pledge SHOULD already "home" domain owner.  The resulting credentials are then used to
   provide credentials more appropriate for a low-latency handoff.

1.3.2.  Constrained enironments

   Questions have been enrolled. 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+) 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 consistant 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.

1.4.  Leveraging the new key infrastructure / next steps

   As a result of the protocol described herein, the bootstrapped
   devices have a common trust anchor and a certificate has optionally
   been issued from a local PKI.  This makes it possible to
   automatically deploy services across the domain in a secure manner.

   Services that benefit from this:

   o  Device management.

   o  Routing authentication.

   o  Service discovery.

   The major 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 flexibility in this document is the result of users 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 following actions are
   required and MUST be performed by the Pledge:

   o  BRSKI: Request Voucher

   o  EST: CA Certificates Request

   o  EST: CSR Attributes

   o  EST: Client Certificate Request

   o  BRSKI: Enrollment status Telemetry

   The ANI Registrar (JRC) MUST support all the BRSKI and above listed
   EST operations.

   All ANI devices SHOULD support the BRSKI proxy function, using
   circuit proxies.  Other proxy methods are optional, and may be
   enabled only if the JRC indicates support for them in it's
   announcement.  (See Section 4.4) 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.  Each component is logical and may be combined with other
   components as necessary.

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

   Figure 1

   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 with a Circuit
   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 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-------+
                |  Discover    |
   +------------>              |
   |            +------+-------+
   |                   |
   |            +------v-------+
   |            |  Identity    |
   ^------------+              |
   | rejected   +------+-------+
   |                   |
   |            +------v-------+
   |            | Request      |
   |            | Join         |
   |            +------+-------+
   |                   |
   |            +------v-------+
   |            |  Imprint     |   Optional
   ^------------+              <--+Manual input (Appendix C)
   | Bad MASA   +------+-------+
   | response          |  send Voucher Status Telemetry
   |            +------v-------+
   |            |  Enroll      |
   ^------------+              |
   | Enroll     +------+-------+
   | Failure           |
   |            +------v-------+
   |            |  Enrolled    |
   ^------------+              |
    Factory     +--------------+
    reset

   Figure 2

   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 can be
       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.  (It enables the Pledge to finish authentication
       of the Registrar TLS server certificate).

   5.  Enroll.  By accepting the domain specific information from a
       Registrar, and by obtaining a domain certificate from a Registrar
       using a standard enrollment protocol, e.g.  Enrollment over
       Secure Transport (EST) [RFC7030].

   6.  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.

2.2.  Secure Imprinting using Vouchers

   A voucher

   After step 4, the pledge has received and authenticated an explicit
   TA (trust anchor) (pinned-domain-cert in the Voucher response).  A
   secure transport exists between pledge and registrar, and it may be
   used for things other than enrollment into a PKI.

2.2.  Secure Imprinting using Vouchers

   A voucher is a cryptographically protected artifact (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 [I-D.ietf-anima-voucher].

   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 server can indiscriminately issue
   vouchers.
   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 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 an
   X.509 a
   PKIX 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 subsequent the protocol exchanges and informing the
   Registrar of the MASA URI.
   described here.  There is no requirement for a common root PKI
   hierarchy.  Each device manufacturer can generate its own root
   certificate.  Specifically, the IDevID:

   1.  Uniquely identifying the pledge by the Distinguished Name (DN)
       and subjectAltName (SAN) parameters in the IDevID.  The following previously defined fields unique
       identification of a pledge in the voucher objects are derived
       from those parameters as described below.

   2.  Securely authentating the pledges identity via TLS connection to
       registrar.  This provides protection against cloned/fake pledged.

   3.  Secure auto-discovery of the pledges MASA by the registrar via
       the MASA URI in IDevID as explained below.

   4.  (Optionally) communicating the X.509 MUD URL (see Appendix D.

   5.  (Optional) Signing of voucher-request by the pledges IDevID
   certificate: to
       enable MASA to generate voucher only to a registrar that has a
       connection to the pledge.

   6.  Authorizing pledge (via registrar) to receive certificate from
       domain CA, by signing the Certificate Signing Request (CSR).

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.

   o  The subject-alt field's encoding SHOULD include a non-critical
      version of the RFC4108 defined HardwareModuleName.

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

   o  An RFC4514 String Representation of the Distinguished Name
      "serialNumber" attribute.

   o  The HardwareModuleName hwSerialNum OCTET STRING base64 encoded.

   o  The RFC4514 String Representation of the Distinguished Name
      "common name" attribute.

2.3.2.  MASA URI extension

   The following newly defined field SHOULD be in the X.509 PKIX IDevID
   certificate: An X.509 A PKIX non-critical certificate extension that contains
   a single Uniform Resource Identifier (URI) that points to an on-line
   Manufacturer Authorized Signing Authority.  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 URI provides the authority
   information.  The BRSKI "/.well-known" tree ([RFC5785]) is described
   in Section 5.

   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>

   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:

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

   Figure 3

2.4.1.  Architectural component: Pledge

   The Pledge is the device that is attempting to join.  Until the
   Pledge completes the enrollment process, it has link-local network
   connectivity only to the Proxy.

2.4.2.  Architectural component: Circuit Proxy

   The (Circuit) Proxy provides HTTPS connectivity between the Pledge
   and the Registrar.  The Proxy circuit proxy mechanism is described in
   Section 4, with an optional stateless proxy mechanism described in
   Appendix C.

2.4.3.  Architectural component: Domain Registrar

   The Domain Registrar (having the formal name Join Registrar/
   Coordinator (JRC), (JRC)), operates as a CMC Registrar, (Certificate
   Management over CMS, see [RFC5272] section 7) terminating the EST and
   BRSKI connections.  The Registrar is manually configured or
   distributed with a list of trust anchors necessary to authenticate
   any Pledge device expected on the network.  The Registrar
   communicates with the MASA to establish ownership.

2.4.4.  Architectural component: Manufacturer Service

   The Manufacturer Service provides two logically seperate functions:
   the Manufacturer Authorized Signing Authority (MASA), (MASA) described in
   Section 5.4 and Section 5.5, and an ownership tracking/auditing function.
   function described in Section 5.6 and Section 5.7.

2.4.5.  Architectural component: Public Key Infrastructure (PKI)

   The Key Infrastructure (PKI) administers certificates for the domain
   of concerns, providing the trust anchor(s) for it and allowing
   enrollment of Pledges with domain certificates.

   The Domain Registrar uses a Trust Anchor (TE) from the PKI in the
   BRSKI Voucher pinned-domain-cert to authenticate itself to the Pledge
   with the help of MASA.  (XXX fix me)

   The Domain Registrar acts as an [RFC5272] Registration Authority,
   requesting certificates for Pledges from the Key Infrastructure.

   The above requirements and expectations against the Key
   Infrastructure are unchanged from RFC7030.  This document does not
   place any additional architectural requirements on the Public Key
   Infrastructure.

2.5.  Certificate Time Validation

2.5.1.  Lack of realtime clock

   Many devices when bootstrapping do not have knowledge of the current
   time.  Mechanisms such as Network Time Protocols cannot be secured
   until bootstrapping is complete.  Therefore bootstrapping is defined
   in a method that does not require knowledge of the current time.

   Unfortunately there are moments during bootstrapping when
   certificates are verified, such as during the TLS handshake, where
   validity periods are confirmed.  This paradoxical "catch-22" is
   resolved by the Pledge maintaining a concept of the current "window"
   of presumed time validity that is continually refined throughout the
   bootstrapping process as follows:

   o  Initially the Pledge does not know the current time.

   o  During Pledge authentiation by the Registrar  Bootstrapping Pledges that have a realtime clock can Realtime Clock (RTC), SHOULD use
      it to verify certificate validity.  However, they MUST be used by prepared
      for the Registrar.  This bullet expands on a closely
      related issue regarding Pledge lifetimes.  RFC5280 indicates recognize that
      long lived Pledge certifiates "SHOULD be assigned the
      GeneralizedTime value of 99991231235959Z" [RFC7030], so the
      Registrar MUST support such lifetimes RTC might be completely wrong when a
      RTC battery fails and SHOULD support ignoring
      Pledge lifetimes if they did not follow the RFC5280
      recommendations. resets to an origin time (e.g., Jan. 1,
      1970)

   o  The Pledge authenticates the voucher presented to it.  During this
      authentication the Pledge ignores certificate lifetimes (by
      necessity because it does not have a realtime clock).

   o  If the voucher contains a nonce then the Pledge MUST confirm the
      nonce matches the original Pledge voucher-request.  This ensures
      the voucher is fresh.  See / (Section 5.2).

   o  Once the voucher is accepted the validity period of the pinned-
      domain-cert in the voucher now serves as a valid time window.  Any
      subsequent certificate validity periods checked during RFC5280
      path validation MUST occur within this window.

   o  When accepting an enrollment certificate the validity period
      within the new certificate is assumed to be valid by the Pledge.
      The Pledge is now willing to use this credential for client
      authentication.

2.5.2.  Infinite Lifetime of IDevID

   [RFC5280] explains that long lived Pledge certificates "SHOULD be
   assigned the GeneralizedTime value 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.

2.6.  Cloud Registrar

   There are transitional situations where devices may be deployed into
   legacy networks that use proprietary bootstrapping mechanisms based
   upon the base EST ([RFC7030]).  The same device may also be deployed
   into an ANIMA environment.  This may be due to incremental
   replacement of a legacy situation with ANIMA.

   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 device might use this
   management interface to learn that it should configure itself by to-
   be-determined mechanism (such as an Intent) to become the local
   Registrar.

   In order to support these scenarios, the Pledge MAY contact a well
   known URI of a cloud Registrar if a local 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 Implicit Trust Anchor database (see [RFC7030]) MUST be used to
   authenticate service as described in [RFC6125].  This is consistent
   with the human user configuration of an EST server URI in [RFC7030]
   which also depends on RFC6125.

2.7.  Determining the MASA to contact

   The Registrar needs to be able to contact a MASA that is trusted by
   the Pledge in order to obtain vouchers.  There are three mechanisms
   described:

   The device's Initial Device Identifier will normally contain the MASA
   URL as detailed in Section 2.3.  This is the RECOMMENDED mechanism.

   If the Registrar is integrated with [I-D.ietf-opsawg-mud] and the
   Pledge IDevID contains the id-pe-mud-url then the Registrar MAY
   attempt to obtain the MASA URL from the MUD file.  The MUD file
   extension for the MASA URL is defined in Appendix D.

   It can be operationally difficult to ensure the necessary X.509
   extensions are in the Pledge's IDevID due to the difficulty of
   aligning current Pledge manufacturing with software releases and
   development.  As a final fallback the Registrar MAY be manually
   configured or distributed with a MASA 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

   The Pledge voucher-request is

   Voucher-requests are how a Pledge requests a voucher. vouchers are requested.  The
   Pledge forms a voucher-request semantics of
   the vouchers are described below, in the YANG model.

   A Pledge forms the "Pledge voucher-request" and submits it to the
   Registrar.

   The Registrar in turn forms the "Registrar voucher-request", and
   submits a voucher-request it to the MASA server.  To
   help differentiate this document refers to "Pledge voucher-request"
   and "Registrar voucher-request" when indicating the source is
   beneficial.

   The "proximity-registrar-cert" leaf defined in this
   section is used in the Pledge voucher-requests. voucher-
   requests.

   The "prior-signed-
   voucher-request" "prior-signed-voucher-request" leaf is be used in Registrar
   voucher-requests that include a to the Pledge voucher-request.  It contains the
   encoded (signed form) of the Pledge voucher-request.

   A Registar MAY also retrieve (nonceless) vouchers by sending voucher-
   requests to the MASA.  No "prior-signed-voucher-request" leaf would
   be included.  This can be used to retrieve vouchers for later offline
   use.  The Registrar will need to know the serial number of the
   pledge.  This document does not provide a mechanism for the Registrar
   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.

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

3.1.  Tree Diagram

   The following tree diagram illustrates a high-level view of a
   voucher-request document.  The notation used in this diagram is
   described in [I-D.ietf-anima-voucher].  Each node in the diagram is
   fully described by the YANG module in Section 3.3.  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

3.2.  Examples

   This section provides voucher voucher-request examples for illustration
   purposes.  These examples conform to the encoding rules defined in
   [RFC7951].

   Example (1)  The following example illustrates a Pledge voucher-
                request.  The assertion leaf is indicated as 'proximity'
                and the Registrar's TLS server certificate is included
                in the 'proximity-registrar-cert' leaf.  See
                Section 5.2.

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

   Example (2)  The following example illustrates a Registrar voucher-
                request.  The 'prior-signed-voucher-request' leaf is
                populated with the Pledge's voucher-request (such as the
                prior example).  The Pledge's voucher-request, if a
                signed artifact with a CMS format signature is a binary
                object.  In the JSON encoding used here it must be
                base64 encoded.  The nonce, created-on and assertion is
                carried forward. serial-number is extracted from the
                Pledge's Client Certificate from the TLS connection.
                See Section 5.4.

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

   Example (3)  The following example illustrates a Registrar voucher-
                request.  The 'prior-signed-voucher-request' leaf is not
                populated with the Pledge's voucher-request nor is the
                nonce leaf.  This form might be used by a Registrar
                requesting a voucher when the Pledge is offline or when
                the Registrar expects to be offline during deployment.
                See Section 5.4.

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

   Example (4)  The following example illustrates a Registrar voucher-
                request.  The 'prior-signed-voucher-request' leaf is not
                populated with the Pledge voucher-request because the
                Pledge did not sign its own request.  This form might be
                used when more constrained Pledges are being deployed.
                The nonce is populated from the Pledge's request.  See
                Section 5.4.

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

3.3.  YANG Module

   Following is a YANG [RFC7950] module formally extending the
   [I-D.ietf-anima-voucher] 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 to access
       the yang-data extension defined in RFC 8040.";
    reference "RFC 8040: RESTCONF Protocol";
  }

  import ietf-voucher {
    prefix v;
    description "This module defines the format for a voucher,
        which is produced by a pledge's manufacturer or
        delegate (MASA) to securely assign a pledge to
        an 'owner', so that the pledge may establish a secure
        conn ection to the owner's network infrastructure";

    reference "RFC YYYY: 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:   Max Pritikin
              <mailto:pritikin@cisco.com>
    Author:   Michael Richardson
              <mailto:mcr+ietf@sandelman.ca>
    Author:   Toerless Eckert
              <mailto:tte+ietf@cs.fau.de>";

  description
   "This module module defines the format for a voucher request.

    It is a superset of the voucher itself.
    This artifact may be optionally signed.
    It provides content to the MASA for consideration
    during a voucher request.

    The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT',
    'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in
    the module text are to be interpreted as described in RFC 2119.

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

    Redistribution and use in source and binary forms, with 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 the IETF Trust's Legal Provisions Relating to IETF Documents
    (http://trustee.ietf.org/license-info).

    This version of this YANG module is part 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;
      }

      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, or re-sign and
             forward a voucher that was previously provided along a
             protocol path, then the previously signed voucher SHOULD be
             included in this field.

             For example, a pledge might sign a proximity voucher, which
             an intermediate registrar then re-signs to make its own
             proximity assertion.  This is a simple mechanism for a
             chain of trusted parties to change a voucher, while
             maintaining the prior signature information.

             The pledge MUST ignore all prior voucher information when
             accepting a voucher for imprinting. Other parties 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 information when signing
             a voucher for imprinting so as to minimize 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 the ASN.1 distinguished encoding
             rules (DER), as specified in ITU-T X.690.

             The first certificate in the Registrar 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 the proximity assertion is
             populated.";
        }
      }
    }
  }

}

<CODE ENDS>
4.  Proxy  Proxying details (Pledge - Proxy - Registrar)

   The role of the Proxy is to facilitate communications.  The Proxy
   forwards packets between the Pledge and a Registrar that has been
   configured on
   provisioned to the Proxy. Proxy via GRASP discovery.

   This section defines a stateful proxy mechanism which is refered to
   as a "circuit" proxy.

   The Proxy does not terminate the TLS handshake: it passes streams of
   bytes onward without examination.

   A Proxy MAY assume TLS framing for auditing purposes, but MUST NOT
   assume any TLS version.

   A Proxy is always

   Registrars are assumed even if it is directly integrated into to have logically a
   Registrar.  (In locally integrated Proxy
   to support directly (subnet) connected Pledges - because Registrars
   themself does not define any functions for Pledges to discover them.
   Such a completely autonomic network, the Registrar MUST logical local proxy does not need to provide Proxy functionality so that it can be discovered, and actual TCP
   proxying (just discovery) as long as the
   network Registrar can grow concentrically around operate with
   subnet (link) local addresses on the Registrar.) interfaces where Pledges may
   connect to.

   As a result of the Proxy Discovery process in Section 4.1.1, the port
   number exposed by the Proxy does not need to be well known, or
   require an IANA allocation.

   If

   In the ANI, the Proxy joins an Autonomic Control Plane
   ([I-D.ietf-anima-autonomic-control-plane]) it SHOULD use Autonomic Control Plane (ACP) secured instance of
   GRASP ([I-D.ietf-anima-grasp]) to discover the MUST be used for discovery of ANI
   Registrar address and port.  As part ACP addresses and ports by ANI Proxies.  The TCP leg of the
   proxy connection between ANI Proxy and ANI Registrar therefore also
   runs across the ACP.

   If GRASP is used by proxies for discovery process, of Registrars (ACP or not),
   the
   Proxy proxy can also learn the proxy mechanism (Circuit Proxy vs vs. IPIP encapsulation) is agreed to
   between the Registrar and Join Proxy.
   encapsulation or other)

   For the IPIP encapsulation methods (described in Appendix C), the
   port announced by the Proxy SHOULD be the same as on the Registrar in
   order for the Proxy to remain stateless.

   In order to permit the Proxy functionality to be implemented on the
   maximum variety of devices the chosen mechanism SHOULD use the
   minimum amount of state on the Proxy device.  While many devices in
   the ANIMA target space will be rather large routers, the Proxy
   function is likely to be implemented in the control plane CPU of such
   a device, with available capabilities 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 is a logical communication with a Registrar,
   through a Proxy.  The Proxy is transparent to the Pledge but is
   always assumed to exist.

   To discover the Proxy the Pledge performs the following actions:

   1.  MUST: Obtains a local address using IPv6 methods as described in
       [RFC4862] IPv6 Stateless Address AutoConfiguration.  Use of
       [RFC4941] temporary addresses is encouraged.  A new temporary
       address SHOULD be allocated whenever the discovery process is
       forced to restart due to failures.  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 for the details of the objective.  The Pledge MAY
       listen concurrently for other sources of information, see
       Appendix B.

   Once a Proxy is discovered the Pledge communicates with a Registrar
   through the Proxy using the bootstrapping protocol defined in
   Section 5.

   Each discovery method attempted

   While the GRASP M_FLOOD mechanism is passive for the Pledge, the
   optional other methods (mDNS, and IPv4 methods) are active.  The
   Pledge SHOULD run those methods in parallel with listening to for the
   M_FLOOD.  The active methods SHOULD exponentially back-off
   attempts (to to a
   maximum of one hour) hour to avoid overloading the network
   infrastructure with discovery. discovery
   attempts.  Detection of change of physical link status (ethernet
   carrier for instance) SHOULD reset the exponential back off.

   The Pledge may discover more than one proxy on a given physical
   interface.  The Pledge may have a multitude of physical interfaces as
   well: a layer-2/3 ethernet switch may have hundreds of physical
   ports.

   Each possible proxy offer SHOULD be attempted up to the point where a
   voucher is received: while there are many ways in which the attempt
   may fail, it does not succeed until the voucher has been validated.

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

   Methods connection attempts.

   Connection attempts SHOULD be run in parallel to avoid head of queue
   problems wherein an attacker running a fake Proxy or Registrar can operate could
   perform protocol actions intentionally slowly.  The Pledge SHOULD
   continue to listen to for additional GRASP M_FLOOD messages during
   the connection attempts.

   Once a connection to a Registrar is established (e.g. establishment
   of a TLS session key) there are expectations of more timely
   responses, see Section 5.2.

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

4.1.1.  Proxy GRASP announcements

   A Proxy uses the DULL GRASP M_FLOOD mechanism to announce itself.  The
   Pledge SHOULD listen for messages of this form.
   This announcement can be within the same message as the ACP
   announcement detailed in [I-D.ietf-anima-autonomic-control-plane].
   The M_FLOOD is formatted as follows:

   [M_FLOOD, 12340815, h'fe80::1', h'fe800000000000000000000000000001', 180000,
               ["AN_Proxy", 4, 1, ""],
               [O_IPv6_LOCATOR,
                    h'fe80::1',
                    h'fe800000000000000000000000000001', 'TCP', 4443]]

   Figure 6b: Proxy Discovery

   The formal 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  ; as in GRASP spec
   sync-only       =  4         ; M_FLOOD only requires synchronization
   loop-count      =  1         ; one hop only
   objective-value =  any         ; none

   locator         = [ O_IPv6_LOCATOR, ipv6-address,
                       transport-proto, port-number ]
   ipv6-address     = the v6 LL of the Proxy
   transport-proto  = IPPROTO_TCP / IPPROTO_UDP / IPPROTO_IPV6
   port-number      = selected by Proxy

   Figure 6c: AN_Proxy CDDL

4.2.  CoAP connection to Registrar

   The use of CoAP to connect from Pledge to Registrar is out of scope
   for this document, and may be described in future work.

4.3.  HTTPS  Proxy connection to discovery of Registrar

   The Proxy Registrar SHOULD also provide one of: an IPIP encapsulation of HTTP
   traffic to the Registrar, or a TCP circuit Proxy that connects the
   Pledge to a Registrar.

   When the Proxy provides a circuit Proxy to a Registrar the Registrar
   MUST accept HTTPS connections.

4.4.  Proxy discovery of Registrar

   The Registrar SHOULD announce itself so 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.  They MUST support ANI TLS circuit Proxy and
   therefore BRSKI across HTTPS/TLS native across the ACP.  ANI
   Registrars MAY support the IPIP proxy method by implementing IPIP
   tunneling for their HTTPS/TLS traffic across the ACP.  ANI Proxies
   MUST support GRASP discovery of Registrars.

   The M_FLOOD is formatted as follows:

   [M_FLOOD, 12340815, h'fda379a6f6ee0000200000064000001', h'fda379a6f6ee00000200000064000001', 180000,
               ["AN_join_registrar", 4, 255, "EST-TLS"],
               [O_IPv6_LOCATOR,
                    h'fda379a6f6ee0000200000064000001',
                    h'fda379a6f6ee00000200000064000001', TCP, 80 80]]

   Figure 7a: 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 the (list of) of supported
                                ; protocols: "EST-TLS" for RFC7030.

   Figure 7: AN_join_registrar CDDL

   The M_FLOOD message MUST be sent periodically.  The period is subject
   to network administrator policy (EST server configuration).  It must
   be sufficiently low that the aggregate amount of periodic M_FLOODs
   from all EST servers causes negligible traffic across the ACP.

   The locators are to be interpreted as follows:

   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 the indicated port is
   desired.  A protocol of 17 indicates that UDP proxying on the
   indicated port is desired.  In each case, the traffic SHOULD be
   proxied to the same port at the ULA address provided.

   A protocol of 41 indicates that packets may be IPIP proxy'ed.  In the
   case of that IPIP proxying is used, then the provided link-local
   address MUST be advertised on the local link using proxy neighbour
   discovery.  The Join Proxy MAY limit forwarded traffic to the
   protocol (6 and 17) and port numbers indicated by locator1 and
   locator2.  The address to which the IPIP traffic should be sent is
   the initiator address (an ACP address of the Registrar), not the
   address given in the locator.

   Registrars MUST accept TCP / UDP traffic on the ports given at the
   ACP address of the Registrar.  If the Registrar supports IPIP
   tunnelling, it MUST also accept traffic encapsulated with IPIP.

   Registrars MUST accept HTTPS/EST traffic on the TCP ports indicated.
   Registrars MAY accept DTLS/CoAP/EST traffic on the UDP ports, in
   addition to TCP traffic.

5.  Protocol Details

   The Pledge MUST initiate BRSKI after boot if it is unconfigured.  The
   Pledge MUST NOT automatically initiate BRSKI if it has been
   configured or is in the process of being configured.

   BRSKI is 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 implements the
   BRSKI REST interface within the same "/.well-known" URI tree as the
   existing EST URIs as described in EST [RFC7030] section 3.2.2.  The
   communication channel between the Pledge and the Registrar is
   referred to as "BRSKI-EST" (see Figure 1).

   The communication channel between the Registrar and MASA is similarly
   described as extensions to EST within the same "/.well-known" tree.
   For clarity this channel is referred to as "BRSKI-MASA".  (See
   Figure 1).

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

   BRSKI uses existing CMS message formats for existing EST operations.
   BRSKI uses JSON [RFC7159] 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, BRSKI-EST connections SHOULD use persistent connections.
   The intention of this guidance is to ensure the provisional TLS
   authentication occurs only once and is properly managed.

   Summarized automation extensions for the BRSKI-EST flow are:

   o  The Pledge provisionally accepts the Registrar certificate during
      the TLS handshake as detailed in Section 5.1.

   o  If the Registrar responds with a redirection to other web origins
      the Pledge MUST follow only a single redirection.  (EST supports
      redirection but does not allow redirections to other web origins
      without user input.)

   o  The Registar MAY respond with an HTTP 202 ("the request has been
      accepted for processing, but the processing has not been
      completed") as described in EST [RFC7030] section 4.2.3 wherein
      the client "MUST wait at least the specified 'retry-after' time
      before repeating the same request".  The Pledge is RECOMMENDED to
      provide local feed (blinked LED etc) during this wait cycle if
      mechanisms for this are available.  To prevent an attacker
      Registrar from significantly delaying bootstrapping the Pledge
      MUST limit the 'retry-after' time to 60 seconds.  To avoid
      blocking on a single erroneous Registrar the Pledge MUST drop the
      connection after 5 seconds in which there has been no progress on
      the TCP connection.  It should proceed to other discovered
      Registrars if there are any.  If there were no other Registrars
      discovered, the Pledge MAY continue to wait, as long as it is
      concurrently listening for new Proxy announcements.

   o  Ideally the Pledge could keep track of the appropriate retry-after
      value for any number of outstanding Registrars but this would
      involve a large state table on the Pledge.  Instead the Pledge MAY
      ignore the exact retry-after value in favor of a single hard coded
      value that takes effect between discovery attempts.  A Registrar
      that is unable to complete the transaction the first time due to
      timing reasons will have future chances.

   o  The Pledge requests and validates a voucher using the new REST
      calls described below.

   o  If necessary the Pledge calls the EST defined /cacerts method to
      obtain the domain owners' CA certificate.  The pinned-domain-
      certificate element from the voucher should validate this
      certificate, or be identical to it.

   o  The Pledge completes authentication of the server certificate as
      detailed in Section 5.5.1.  This moves the BRSKI-EST TLS
      connection out of the provisional state.  Optionally, the BRSKI-
      EST TLS connection can now be used for EST enrollment.

   The extensions for 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.
      The subject field's DN encoding MUST include the "serialNumber"
      attribute with the device's unique serial number.  In the language
      of [RFC6125] this provides for a SERIALNUM-ID category of
      identifier that can be included in a certificate and therefore
      that can also be used for matching purposes.  The SERIALNUM-ID
      whitelist is collated according to manufacturer trust anchor since
      serial numbers are not globally unique.

   o  The Registrar requests and validates the Voucher from the MASA.

   o  The Registrar forwards the Voucher to the Pledge when requested.

   o  The Registar performs log verifications in addition 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 proxy (see Section 4) but the TLS handshake is with the
   Registar.  The BRSKI-EST Pledge is the TLS client and the BRSKI-EST
   Registrar is the TLS server.  All security associations established
   are between the Pledge and the Registrar regardless of proxy
   operations.

   Establishment of 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 the IDevID
   certificate, and the EST server (the Registrar) is provisionally
   authenticated with an unverified server certificate.

   The Pledge maintains a security paranoia concerning the provisional
   state, and all data received, until a voucher is received and
   verified as specified in Section 5.5.1

5.2.  Pledge Requests Voucher from the Registrar

   When the Pledge bootstraps it makes a request for a Voucher from a
   Registrar.

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

   The request media types are:

   application/voucher-cms+json  The request 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].  The
      Pledge SHOULD sign the request using the Section 2.3 credential.

   application/json  The request is the "YANG-defined JSON document" as
      described in Section 3 with the exception that it is not within a
      PKCS#7 structure.  It is protected only by the TLS client
      authentication.  This reduces the cryptographic requirements on
      the Pledge.

   For simplicity the term 'voucher-request' is used to refer to either
   of these media types.  Registrar impementations SHOULD anticipate
   future media types but of course will simply fail the request if
   those types are not yet known.

   The Pledge populates the voucher-request fields as follows:

   created-on:  Pledges that have a realtime clock are RECOMMENDED to
      populate this field.  This provides additional information to the
      MASA.

   nonce:  The Pledge voucher-request MUST contain a cryptographically
      strong random or pseudo-random number nonce.  Doing so ensures
      Section 2.5 2.5.1 functionality.  The nonce MUST NOT be reused for
      bootstrapping attempts.

   assertion:  The Pledge voucher-request MAY contain an assertion of
      "proximity".

   proximity-registrar-cert:  In a Pledge voucher-request this is the
      first certificate in the TLS server 'certificate_list' sequence
      (see [RFC5246]) presented by the Registrar to the Pledge.  This
      MUST be populated in a Pledge voucher-request if the "proximity"
      assertion is populated.

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

   An example JSON payload of a Pledge voucher-request is in Section 3.2
   Example 1.

   The Registrar validates the client identity as described in EST
   [RFC7030] section 3.3.2.  If the request is signed the Registrar
   confirms that the 'proximity' asserion and associated 'proximity-
   registrar-cert' are correct.  The Registrar performs authorization as
   detailed in [[EDNOTE: UNRESOLVED.  See Appendix D "Pledge
   Authorization"]].  If these validations fail the Registrar SHOULD
   respond with an appropriate HTTP error code.

   If authorization is successful the Registrar obtains a voucher from
   the MASA service (see Section 5.4) and returns that MASA signed
   voucher to the Pledge as described in Section 5.5.

5.3.  BRSKI-MASA TLS establishment details

   The BRSKI-MASA TLS connection is a 'normal' TLS connection
   appropriate for HTTPS REST interfaces.  The Registrar initiates the
   connection and uses the MASA URL obtained as described in Section 2.7
   for [RFC6125] authentication of the MASA server.

   The primary method of Registrar "authentication" by the MASA is
   detailed in Section 5.4.  As detailed in Section 8 the MASA might
   find it necessary to request additional Registrar authentication.
   Registrars MUST be prepared to support TLS client certificate
   authentication and HTTP Basic or Digest authentication as described
   in RFC7030 for EST clients.  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 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.

5.4.  Registrar Requests Voucher from MASA

   When a Registrar receives a Pledge voucher-request it in turn submits
   a Registrar voucher-request to the MASA service.  For simplicity this
   is defined as an optional EST message between a Registrar and an EST
   server running on the MASA service although the Registrar is not
   required to make use of any other EST functionality when
   communicating with the MASA service.  (The MASA service MUST properly
   reject any EST functionality requests it does not wish to service; a
   requirement that holds for any REST interface).

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

   The request media type is defined in [I-D.ietf-anima-voucher] and is
   application/voucher-cms+json.  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 the Domain CA, MUST be included in the PKCS#7 structure.

   MASA impementations SHOULD anticipate future media types but of
   course will simply fail the request if those types are not yet known.

   The Registrar populates the voucher-request fields as follows:

   created-on:  Registrars are RECOMMENDED to populate this field.  This
      provides additional information to the MASA.

   nonce:  The optional nonce value from the Pledge request if desired
      (see below).

   serial-number:  The serial number of the Pledge the Registrar would
      like a voucher for.

   idevid-issuer:  The idevid-issuer value from the Pledge certificate
      is included to ensure a statistically unique identity.  The
      Pledge's serial number is extracted from the X.509 IDevID.  See
      Section 2.3.

   prior-signed-voucher:  If a signed Pledge voucher-request was
      received then it SHOULD be included in the Registrar voucher-
      request.  (NOTE: what is included is the complete Pledge voucher-
      request, inclusive of the 'assertion', 'proximity-registrar-cert',
      etc wrapped by the Pledge's original signature).

   A nonceless Registrar voucher-request MAY be submitted to the MASA.
   Doing so allows the Registrar to request a Voucher when the Pledge is
   offline, or when the Registrar is expected to be offline when the
   Pledge is being deployed.  These use cases require the Registrar to
   learn the appropriate IDevID SerialNumber field from the physical
   device labeling or from the sales channel (out-of-scope for this
   document).  If a nonceless voucher-reqeust is submitted the MASA
   server MUST authenticate the Registrar as described in either EST
   [RFC7030] section 3.2, section 3.3, or by validating the Registrar's
   certificate used to sign the Registrar voucher-request.  Any of these
   methods reduce the risk of DDoS attacks and provide an authenticated
   identity as an input to sales channel integration and authorizations
   (the actual sale-channel integration is also out-of-scope of this
   document).

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

   Example JSON payloads of Registrar voucher-requests are in
   Section 3.2 Examples 2 through 4.

   The MASA verifies that the Registrar voucher-request is internally
   consistent but does not necessarily authenticate the Registrar
   certificate since the Registrar is not known to the MASA server in
   advance.  The MASA performs the following actions and validation
   checks before issuing a voucher:

   Renew for expired voucher:  As described in [I-D.ietf-anima-voucher]
      vouchers are normally short lived to avoid revocation issues.  If
      the request is for a previous (expired) voucher using the same
      Registrar (as determined by the Registrar pinned-domain-cert) and
      the MASA has not been informed that the claim is invalid then the
      request for a renewed voucher SHOULD be automatically authorized.

   Voucher signature consistency:  The MASA MUST verify that the
      Registrar voucher-request is signed by a Registrar.  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 certificate of the entity that signed the Registrar
      voucher-request.  This verification is only a consistency check
      that the unauthenticated domain CA intended this to be a
      Registrar.  Performing this check provides value to domain PKI by
      assuring the domain administrator that the MASA service will only
      respect claims from authorized Registration Authorities of the
      domain.  (The requirement for the Registrar to include the Domain
      CA certificate in the signature structure was stated above.)

   Registrar revocation consistency:  The MASA SHOULD check for
      revocation of the Registrar certificate.  The maximum lifetime of
      the voucher issued SHOULD NOT exceed the lifetime of the
      Registrar's revocation validation (for example if the Registrar
      revocation status is indicated in a CRL that is valid for two
      weeks then that is an appropriate lifetime for the voucher.)
      Because the Registar certificate authority is unknown to the MASA
      in advance this is only an extended consistency check and is not
      required.  The maximum lifetime of the voucher issued SHOULD NOT
      exceed the lifetime of the Registrar's revocation validation (for
      example if the Registrar revocation status is indicated in a CRL
      that is valid for two weeks then that is an appropriate lifetime
      for the voucher.)

   Pledge proximity assertion:  The MASA server MAY verify that the
      Registrar voucher-request includes the 'prior-signed-voucher'
      field populated with a Pledge voucher-request that includes a
      'proximity-registrar-cert' that is consistent with the certificate
      used to sign the Registrar voucher-request.  The MASA server is
      aware of which Pledge's support signing of their voucher requests
      and can use this information to confirm proximity of the Pledge
      with the Registrar.

   Registar (certificate) authentication:  This only occurs if the
      Registrar voucher-request is nonceless.  As noted above the
      details concerning necessary sales-channel integration for the
      MASA to authenticate a Registrar certificate is out-of-scope.

   The Registrar's certificate chain is extracted from the signature
   method and the root certificate is used to populate the "pinned-
   domain-cert" of the Voucher being issued.  The domainID (e.g., hash
   of the root public key) is determined from the pinned-domain-cert and
   is used to update the audit log.

5.5.  Voucher Response

   The voucher response to requests from the Pledge and requests from a
   Registrar are in the same format.  A Registrar either caches prior
   MASA responses or dynamically requests a new Voucher based on local
   policy.

   If the join operation is successful, the server response MUST contain
   an HTTP 200 response code.  The server MUST answer with a suitable
   4xx or 5xx HTTP [RFC2616] error code when a problem occurs.  In this
   case, the response data from the MASA server MUST be a plaintext
   human-readable (ASCII, English) error message containing explanatory
   information describing why the request was rejected.

   A 403 (Forbidden) response is appropriate if the voucher-request is
   not signed correctly, stale, or if the Pledge has another outstanding
   voucher that cannot be overridden.

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

   A 406 (Not Acceptable) response is appropriate if a voucher of the
   desired type, or using the desired algorithms (as indicated by the
   Accept: headers, and algorithms used in the signature) cannot be
   issued, such as because the MASA knows the Pledge cannot process that
   type.

   A 415 (Unsupported Media Type) response is approriate for a request
   that has a voucher encoding that is not understood.

   The response media type is:

   application/pkcs7-mime; smime-type=voucher  The response is a "YANG-
      defined JSON document that has been signed using a PKCS#7
      structure" as described in [I-D.ietf-anima-voucher] using the JSON
      encoded described in [RFC7951].  The MASA MUST sign the request.

   The syntactic details of vouchers are described in detail in
   [I-D.ietf-anima-voucher].  For example, the voucher consists of:

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

   The Pledge verifies the signed voucher using the manufacturer
   installed trust anchor associated with the manufacturer's selected
   Manufacturer Authorized Signing Authority.

   The 'pinned-domain-cert' element of the voucher contains the domain
   CA's public key.  The Pledge MUST use the 'pinned-domain-cert' trust
   anchor to immediately complete authentication of the provisional TLS
   connection.

   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 to ignore additional fields that it does
   not recognize.

5.5.1.  Completing authentication of Provisional TLS connection

   If a Registrar's credentials cannot be verified using the pinned-
   domain-cert trust anchor from the voucher then the TLS connection is
   immediately discarded and the Pledge abandons attempts to bootstrap
   with 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 the same proxy again after attempting
   with other proxies.  Attempts should be attempted in the exponential
   backoff described earlier.  Attempts SHOULD be repeated as failure
   may be the result 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 the
   EST connection.

   The Registrar MUST use a certificate that chains to the pinned-
   domain-cert as its TLS server certificate.

   The Pledge's PKIX path validation of a Registrar certificate's
   validity period information is as described in Section 2.5. 2.5.1.  Once
   the PKIX path validation is successful the TLS connection is no
   longer provisional.

   The pinned-domain-cert is installed as an Explicit Trust Anchor for
   future operations.  It can therefore can be used to authenticate any
   dynamically discovered EST server that contain the id-kp-cmcRA
   extended key usage extension as detailed in EST RFC7030 section
   3.6.1; but to reduce system complexity the Pledge SHOULD avoid
   additional discovery operations.  Instead the Pledge SHOULD
   communicate directly with the Registrar as the EST server.  The
   'pinned-domain-cert' is not a complete distribution of the EST
   section 4.1.3 CA Certificate Response, which is an additional
   justification for the recommendation to proceed with EST key
   management operations.  Once a full CA Certificate Response is
   obtained it is more authoritative for the domain than the limited
   'pinned-domain-cert' response.

5.6.  Voucher Status Telemetry

   The domain is expected to provide indications to the system
   administrators concerning device lifecycle status.  To facilitate
   this it needs telemetry information concerning the device's status.

   To indicate Pledge status regarding the Voucher, the Pledge MUST post
   a status message.

   The posted data media type: application/json
   The client HTTP POSTs the following to the server at the EST well
   known URI "/voucher_status".  The Status field indicates if the
   Voucher was acceptable.  If it was not acceptable the Reason string
   indicates why.  In the failure case this message is being sent to an
   unauthenticated, potentially malicious Registrar and therefore the
   Reason string SHOULD NOT provide information beneficial to an
   attacker.  The operational benefit of this telemetry information is
   balanced against the operational costs of not recording that an
   Voucher was ignored by a client the registar expected to continue
   joining the domain.

   {
     "version":"1",
     "Status":FALSE /* TRUE=Success, FALSE=Fail"
     "Reason":"Informative human readable message"
     "reason-context": { additional JSON }
   }

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

   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.

   Additional standard responses MAY be added via Specification
   Required.

5.7.  MASA authorization log Request

   After receiving the voucher status telemetry Section 5.6, the
   Registrar SHOULD request the MASA authorization log from the MASA
   service using this EST extension.  If a device had previously
   registered with another domain, a Registrar of that domain would show
   in the log.

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

   The Registrar MUST HTTP POST the same Registrar voucher-request as it
   did when requesting a Voucher.  It is posted to the /requestauditlog
   URI instead.  The "idevid-issuer" and "serial-number" informs the
   MASA server 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 server implementation
   MAY leverage internal state to associate this request with the
   original, and by now already validated, Registrar voucher-request so
   as to avoid an extra crypto validation.

   A MASA that receives a request for a device which 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")
   RESTful response ([RFC7231] section 7.1) containing a URL to the
   prepared (and easily cachable) audit response.

   MASA servers that return URLs SHOULD take care to make the returned
   URL unguessable.  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, would be easily
   enumerable by an attacker.  It is recommended to put some meaningless
   randomly generated slug that indexes a database instead.

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

   The request media type is:

   application/voucher-cms+json  The request is a "YANG-defined JSON
      document that has been signed using a CMS structure" as described
      in Section 3 using the JSON encoded described in [RFC7951].  The
      Registrar MUST sign the request.  The entire Registrar certificate
      chain, up to and including the Domain CA, MUST be included in the
      CMS structure.

5.7.1.  MASA authorization log Response

   A log data file is returned consisting of all log entries.  For
   example:

   {
     "version":"1",
     "events":[
       {
        "date":"<date/time of the entry>",
        "domainID":"<domainID extracted from voucher-request>",
        "nonce":"<any nonce if supplied (or the exact string 'NULL')>"
       },
       {
        "date":"<date/time of the entry>",
        "domainID":"<domainID extracted from voucher-request>",
        "nonce":"<any nonce if supplied (or the exact string 'NULL')>"
       }
     ],
     "truncation": {
       "nonced duplicates": <number of entries truncated>,
       "nonceless duplicates": <number of entries truncated>,
       "arbitrary": <number of entries trucated>
       }
   }

   A Registrar SHOULD use this log information to make an informed
   decision regarding the continued bootstrapping of the Pledge.  For
   example if the log includes an unexpected domainID then the Pledge
   could have imprinted on an unexpected domain.  If the log includes
   nonceless entries then any Registrar in the same domain could
   theoretically trigger a reset of the device and take over management
   of the Pledge.  Equipment that is purchased pre-owned can be expected
   to have an extensive history.  A Registrar MAY request logs at future
   times.  A Registrar MAY be configured to ignore the history of the
   device but it is RECOMMENDED that this only be configured if hardware
   assisted NEA [RFC5209] is supported.

   Log entries can be compared against local history logs in search of
   discrepancies.

   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 truncated from the log leaving only the single most
   recent nonced or nonceless entry.  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 truncated for length.  The trunctation method(s) used
   MUST be indicated in the JSON truncation dictionary using "nonced
   duplicates", "nonceless duplicates", and "arbitrary" where the number
   of entries that have been truncation is indicated.  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 truncated
   ("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.

   This document specifies a simple log format as provided by the MASA
   service to the registar.  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 improvements 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.  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.

   The Pledge is also RECOMMENDED to implement the EST automation
   extensions described below.  They supplement the RFC7030 EST to
   better support automated devices that do not have an end user.

   Although EST allows clients to obtain multiple certificates by
   sending multiple CSR requests BRSKI mandates use of the CSR
   Attributes request and mandates that the Registrar 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.  Pledges that require
   multiple certificates could establish direct EST connections to the
   Registrar.

5.8.1.  EST Distribution of CA Certificates

   The Pledge MUST 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 5.5.1 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.

5.8.2.  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 boostrapping
   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 attributes MUST include the
   "ACP information" field.  See
   [I-D.ietf-anima-autonomic-control-plane] for more details.

   The Registar MUST also confirm that the resulting CSR is formatted as
   indicated before forwarding the request to a CA.  If the Registar 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.

5.8.3.  EST Client Certificate Request

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

5.8.4.  Enrollment Status Telemetry

   For automated bootstrapping of devices, the adminstrative 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, MASA provides logs and status of credential
   enrollment.  The EST protocol assumes an end user and therefore does
   not include a final success indication back to the server.  This is
   insufficient for automated use cases.

   To indicate successful enrollment the client SHOULD re-negotiate the
   EST TLS session using the newly obtained credentials.  This occurs by
   the client initiating a new TLS ClientHello message on the existing
   TLS connection.  The client MAY simply close the old TLS session and
   start a new one.  The server MUST support either model.

   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.

   Status media type: application/json

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

   {
     "version":"1",
     "Status":TRUE /* TRUE=Success, FALSE=Fail"
     "Reason":"Informative human readable message"
     "reason-context": "Additional information"
   }

   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.
   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 the server not being able to accurately verify that
   enrollment was truly successful.

5.8.5.  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 defintion 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.vanderstok-ace-coap-est] and that
   CoAP mappings for BRSKI will be discussed either there or in future
   work.

6.  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.

6.1.  Trust Model

   +--------+         +---------+    +------------+     +------------+
   | Pledge |         | Circuit |    | 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.

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

   Registrar:  When interacting with a MASA server a Registrar makes all
      decisions.  When Ownership Vouchers are involved a Registrar is
      only a conduit and all security decisions are made on the
      manufacturer service.

   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.
      Current text provides only for a trusted manufacturer.

   Vendor Service, Ownership Validation:  This form of manufacturer
      service is trusted to accurately know which device is owned by
      which domain.

6.2.  Pledge security reductions

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

   1.  The Pledge MUST accept nonceless vouchers.  This allows for
       offline use cases.  Logging and validity periods address the
       inherent security considerations of supporting these use cases.

   2.  The Pledge MAY support "trust on first use" for physical
       interfaces such as a local console port or physical user
       interface but MUST NOT support "trust on first use" on network
       interfaces.  This is because "trust on first use" permanently
       degrades the security for all use cases.

   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 can be useful
       if the manufacturer service is unavailable.  This behavior SHOULD
       be available via local configuration or physical presence methods
       to ensure new entities can always be deployed even when autonomic
       methods fail.  This allows for unsecured imprint.

   It is RECOMMENDED that "trust on first use" or skipping voucher
   validation only be available if hardware assisted Network Endpoint
   Assessment [RFC5209] is supported.  This recommendation ensures that
   domain network monitoring can detect innappropriate use of offline or
   emergency deployment procedures.

6.3.  Registrar security reductions

   A Registrar can choose to accept devices using less secure methods.
   These methods are acceptable when low security models are needed, as
   the security decisions are being made by the local administrator, but
   they MUST NOT be the default behavior:

   1.  A Registrar MAY choose to accept all devices, or all devices of a
       particular type, at the administrator's discretion.  This could
       occur when informing all Registrars of unique identifiers of new
       entities might be operationally difficult.

   2.  A Registrar MAY choose to accept devices that claim a unique
       identity without the benefit of authenticating that claimed
       identity.  This could occur when the Pledge 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
       the Section 5.4 format to ensure the Pledge's serial number
       information is provided to the Registar (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 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
       to do so by an administrator that has verified that only expected
       new entities can communicate with a Registrar (presumably via a
       physically secured perimeter.)

   3.  A Registrar MAY submit a nonceless voucher-requests to the MASA
       service (by not including a nonce in the voucher-request.)  The
       resulting Vouchers can then be stored by the Registrar until they
       are needed during bootstrapping operations.  This is for use
       cases where the target network is protected by an air gap and
       therefore cannot contact the MASA service during Pledge
       deployment.

   4.  A Registrar MAY ignore unrecognized nonceless log entries.  This
       could occur when used equipment is purchased with a valid history
       being deployed in air gap networks that required permanent
       Vouchers.

6.4.  MASA security reductions

   Lower security modes chosen by the MASA service affect all device
   deployments unless bound to the specific device identities.  In which
   case these modes can be provided as additional features for specific
   customers.  The MASA service can choose to run in less secure modes
   by:

   1.  Not enforcing that a nonce is in the Voucher.  This results in
       distribution of a Voucher that never expires and in effect makes
       the Domain an always trusted entity to the Pledge during any
       subsequent bootstrapping attempts.  That this occurred is
       captured in the log information so that the Registrar can make
       appropriate security decisions when a Pledge joins the Domain.
       This is useful to support use cases where Registrars might not be
       online during actual device deployment.  Because this results in
       a long lived Voucher and does not require the proof that the
       device is online, this is only accepted when the Registrar is
       authenticated by the MASA server and authorized to provide this
       functionality.  The MASA server is RECOMMENDED to use this
       functionality only in concert with an enhanced level of ownership
       tracking (out-of-scope.)  If the Pledge device is known to have a
       real-time-clock 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 to be a common operational model because doing so
       relieves the manufacturer providing MASA services from having 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 in depth strategy to ensure that this
       does not occur unexpectedly (for example when purchasing new
       equipment the Registrar would throw an error if any audit log
       information is reported.)  The MASA should verify the 'prior-
       signed-voucher' information for Pledges that support that
       functionality.  This provides a proof-of-proximity check that
       reduces the need for ownership verification.

7.  IANA Considerations

   This document requires the following IANA actions:

7.1.  PKIX Registry

   IANA is requested to register the following:

   This document requests a number for id-mod-MASAURLExtn2016(TBD) from
   the pkix(7) id-mod(0) Registry.  [[EDNOTE: fix names]]

   This document requests a number from the id-pe registry for id-pe-
   masa-url.  XXX

7.2.  Voucher Status Telemetry

   IANA is requested to create a registry entitled: _Voucher Status
   Telemetry Attributes_.  New items can be added using the
   Specification Required.  The following items are to be in the initial
   registration, with this document as the reference:

   o  version

   o  Status

   o  Reason

   o  reason-context

8.  Security Considerations

   There are uses cases where the MASA could be unavailable or
   uncooperative to the Registrar.  They include planned and unplanned
   network partitions, changes to MASA policy, or other instances where
   MASA policy rejects a claim.  These introduce an operational risk to
   the Registrar owner that MASA behavior might limit the ability to re-
   boostrap 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 guaranteed to be able to repeat bootstrapping for
   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 can use a previously issued nonceless
   voucher to establish management control of a Pledge device even after
   having sold it.  This risk is mitigated by recording the issuance of
   such vouchers in the MASA audit log that is verified by the
   subsequent Registrar.  This reduces the resale value of the equipment
   because future owners will detect the lowered security inherent in
   the existence of a nonceless voucher that would be trusted by their
   Pledge.  This reflects a balance between partition resistant recovery
   and security of future bootstrapping.  Registrars take the Pledge's
   audit history into account when applying policy to new devices.

   The MASA server is exposed to DoS attacks wherein attackers claim an
   unbounded number of 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 Pledge voucher-request, as forwarded by the
   Registrar in the prior-signed-voucher field of the Registrar voucher-
   request, significantly reduce this risk by ensuring the MASA can
   confirm proximity between the Pledge and the Registrar making the
   request.  This mechanism is optional to allow for constrained
   devices.

   To facilitate logging and administrative oversight in addition to
   triggering Registration verification of MASA logs the Pledge reports
   on Voucher parsing status to the Registrar.  In the case of a
   failure, this information is informative to a potentially malicious
   Registar but this is mandated anyway because of the operational
   benefits of an informed administrator in cases where the failure is
   indicative of a problem.  The Registrar is RECOMMENDED to verify MASA
   logs if voucher status telemetry is not received.

   The MASA authorization 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, especially when paired with
   the anti-DDoS authentication information the MASA might collect.
   This could provide sufficient information for the MASA service to
   build a detailed understanding the devices that have been provisioned
   within a domain.  There are a number of design choices that mitigate
   this risk.  The domain can maintain some privacy since it has not
   necessarily been authenticated and 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 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 a significant level of privacy while maintaining the
   security characteristics provided by Registrar based audit log
   inspection.

   To facilitate truely limited clients EST RFC7030 section 3.3.2
   requirements that the client MUST support a client authentication
   model have been reduced in Section 6 to a statement that the
   Registrar "MAY" choose to accept devices that fail cryptographic
   authentication.  This reflects current (poor) practices in shipping
   devices without a cryptographic identity that are NOT RECOMMENDED.

   During the provisional period of the connection the 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 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 failure and the Pledge choses whichever
   voucher to accept based on internal logic.  The Registrar's verifying
   log information will see multiple entries and take this into account
   for their analytics purposes.

8.1.  Freshness in Voucher-Requests

   A concern has been raised that the Pledge voucher-request should
   contain some content (a nonce) provided by the Registrar and/or MASA
   in order for those actors to verify that the Pledge voucher-request
   is fresh.

   There are a number of operational problems with getting a nonce from
   the MASA to the Pledge.  It is somewhat easier to collect a random
   value 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 to addressing these operational issues, so if
   such a thing were to be considered, it would have to provide some
   clear value.  This section examines the impacts of not having a fresh
   Pledge voucher-request.

   Because the Registrar authenticates the Pledge, a full Man-in-the-
   Middle attack is not possible, despite the provisional TLS
   authentication by the Pledge (see Section 5.)  Instead we examine the
   case of a fake Registrar (Rm) that communicates with the Pledge in
   parallel or in close time proximity with the intended Registrar.
   (This scenario is intentionally supported as described in
   Section 4.1.)

   The fake Registrar (Rm) can obtain a voucher signed by the MASA
   either directly or through arbitrary intermediaries.  Assuming that
   the MASA accepts the Registar voucher-request (either because Rm is
   collaborating with a legitimate Registrar according to supply chain
   information, or because the MASA is in audit-log only mode), then a
   voucher linking the Pledge to the Registrar Rm is issued.

   Such a voucher, when passed back to the 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 Rm with full administrative control, can be assumed
   to be a threat against the intended Registrar.

   This flow is mitigated by the intended Registar verifying the audit
   logs available from the MASA as described in Section 5.7.  Rm might
   chose to wait until after the intended Registrar completes the
   authorization process before submitting the now-stale Pledge voucher-
   request.  The Rm would need need to remove the Pledge's nonce.

   In order to successfully use the resulting "stale voucher" Rm would
   have to attack the Pledge and return it to a bootstrapping enabled
   state.  This would require wiping the Pledge of current configuration
   and triggering a re-bootstrapping of the Pledge.  This is no more
   likely than simply taking control of the Pledge directly but if this
   is a consideration the target network is RECOMMENDED to take the
   following steps:

   o  Ongoing network monitoring for unexpected bootstrapping attempts
      by Pledges.

   o  Retreival and examination of MASA log information upon the
      occurance of any such unexpected events.  Rm will be listed in the
      logs.

8.2.  Trusting manufacturers

   The BRSKI extensions to EST permit a new pledge to be completely
   configured with domain specific trust anchors.  The link from built-
   in 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 risk that the network will accept a pledge that
   should not be a member of the network.  As the address of the
   manufacturer's MASA is provided in the IDevID using the extension
   from Section 2.3, the malicious pledge will have no problem
   collaborating with it's MASA to produce a completely valid voucher.

   BRSKI does not, however, fundamentally change the trust model from
   domain owner to manufacturer.  Assuming that the pledge used its
   IDevID with RFC7030 EST and BRSKI, the domain (registrar) still needs
   to trust the manufacturer.

   Establishing this trust between domain and manufacturer is outside
   the scope of BRSKI.  There are a 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 trust anchor would be installed to remove the Pledge's nonce.

   In order to successfully use trusted store.
      There are risks with this; even if the resulting "stale voucher" Rm would
   have key to attack name is validated
      using something like the Pledge and return it to a bootstrapping enabled
   state.  This would require wiping WebPKI, there remains the Pledge of current configuration
   and triggering a re-bootstrapping of possibility
      that the Pledge.  This name is no more
   likely than simply taking control of a look alike: e.g, c1sco.com, ..

   o  scanning the Pledge directly but if this
   is trust anchor from a consideration QR code that came with the target network
      packaging (this is RECOMMENDED to take really a manual TOFU mechanism)

   o  some sales integration process where trust anchors are provided as
      part of the
   following steps: sales process, probably included in a digital packing
      "slip", or a sales invoice.

   o  Ongoing network monitoring  consortium membership, where all manufacturers of a particular
      device category (e.g, a light bulb, or a cable-modem) are signed
      by an certificate authority specifically for unexpected bootstrapping attempts this.  This is done
      by Pledges.

   o  Retreival CableLabs today.  It is used for authentication and examination
      authorization as part of MASA log information upon TR-79: [docsisroot] and [TR069].

   The existing WebPKI provides a reasonable anchor between manufacturer
   name and public key.  It authenticates the
      occurance of any such unexpected events.  Rm will be listed in key.  It does not provide
   a reasonable authorization for the
      logs. manufacturer, so it is not
   directly useable on it's own.

9.  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,
   and Peter van der Stok

10.  References

10.1.  Normative References

   [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-13 (work in progress), December 2017.

   [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.

   [I-D.ietf-anima-voucher]
              Watsen, K., Richardson, M., Pritikin, M., and T. Eckert,
              "Voucher Profile for Bootstrapping Protocols", draft-ietf-
              anima-voucher-07 (work in progress), January 2018.

   [IDevID]   IEEE Standard, "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>.

   [RFC3542]  Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei,
              "Advanced Sockets Application Program Interface (API) for
              IPv6", RFC 3542, DOI 10.17487/RFC3542, May 2003,
              <https://www.rfc-editor.org/info/rfc3542>.

   [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>.

   [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>.

   [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>.

   [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>.

10.2.  Informative References

   [docsisroot]
              CableLabs, "CableLabs Digital Certificate Issuance
              Service", February 2018,
              <https://www.cablelabs.com/resources/
              digital-certificate-issuance-service/>.

   [I-D.ietf-anima-reference-model]
              Behringer, M., Carpenter, B., Eckert, T., Ciavaglia, L.,
              Pierre, P., Liu, B., Nobre, J., and J. Strassner, "A
              Reference Model for Autonomic Networking", draft-ietf-
              anima-reference-model-05 (work in progress), October 2017.

   [I-D.ietf-netconf-zerotouch]
              Watsen, K., Abrahamsson, M., and I. Farrer, "Zero Touch
              Provisioning for NETCONF or RESTCONF based Management",
              draft-ietf-netconf-zerotouch-19 Networking Devices", draft-ietf-netconf-
              zerotouch-20 (work in progress),
              October 2017. February 2018.

   [I-D.ietf-opsawg-mud]
              Lear, E., Droms, R., and D. Romascanu, "Manufacturer Usage
              Description Specification", draft-ietf-opsawg-mud-15 draft-ietf-opsawg-mud-18 (work
              in progress), January March 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.

   [I-D.vanderstok-ace-coap-est]
              Stok, P., Kampanakis, P., Kumar, S., Richardson, M.,
              Furuhed, M., and S. Raza, "EST over secure CoAP (EST-
              coaps)", draft-vanderstok-ace-coap-est-04 (work in
              progress), January 2018.

   [imprinting]
              Wikipedia, "Wikipedia article: Imprinting", July 2015,
              <https://en.wikipedia.org/wiki/Imprinting_(psychology)>.

   [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>.

   [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>.

   [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>.

   [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>.

   [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>.

   [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]    Broadband Forum, "TR-69: CPE WAN Management Protocol",
              February 2018, <https://www.broadband-forum.org/
              standards-and-software/technical-specifications/
              tr-069-files-tools>.

Appendix A.  IPv4 operations

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

   The Pledge MAY perform DNS-based Service Discovery [RFC6763] over
   Multicast DNS [RFC6762] searching for the service
   "_bootstrapks._tcp.local.".

   To prevent unaccceptable levels of network traffic 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.

   The service searched for is "_bootstrapks._tcp.example.com".  In this
   case the domain "example.com" is discovered as described in [RFC6763]
   section 11.  This method is only available if the host has received a
   useable IPv4 address via DHCPv4 as suggested in Appendix A.2.

   If no local bootstrapks service is located using the GRASP
   mechanisms, or the above mentioned DNS-based Service Discovery
   methods, the Pledge MAY contact a well known manufacturer provided
   bootstrapping server by performing a DNS lookup using a well known
   URI such as "bootstrapks.manufacturer-example.com".  The details of
   the URI are manufacturer specific.  Manufacturers that leverage this
   method on the Pledge are responsible for providing the bootstrapks
   service.

   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.  IPIP Join Proxy mechanism

   The Circuit Proxy mechanism suffers from requiring a state on the
   Join Proxy for each connection that is relayed.  The Circuit Proxy
   can be considered a kind of Algorithm Gateway (see [RFC2663], section
   2.9).

   An alternative to proxying at the TCP layer is to selectively forward
   at the IP layer.  This moves all per-connection to the Join
   Registrar.  The IPIP tunnel statelessly forwards packets.  This
   section provides some explanation of some of the details of the
   Registrar discovery procotol, which are not important to Circuit
   Proxy, and some implementation advice.

   The IPIP tunnel is described in [RFC2473].  Each such tunnel is
   considered a unidirectional construct, but two tunnels may be
   associated to form a bidirectional mechanism.  An IPIP tunnel is
   setup as follows.  The outer addresses are an ACP address of the Join
   Proxy, and the ACP address of the Join Registrar.  The inner
   addresses seen in the tunnel are the link-local addresses of the
   network on which the join activity is occuring.

   One way to look at this construct is to consider that the Registrar
   is extending attaching an interface to the network on which the Join
   Proxy is physically present.  The Registrar then interacts as if it
   were present on that network using link-local (fe80::) addresses.
   The Join node is unaware that the traffic is being proxied through a
   tunnel, and does not need any special routing.

   There are a number of considerations with this mechanism which cause
   some minor amounts of complexity.  Note that due to the tunnels, the
   Registrar sees multiple connections to a fe80::/10 network on not
   just physical interfaces, but on each of the virtual interfaces
   representing the tunnels.

C.1.  Multiple Join networks on the Join Proxy side

   The Join Proxy will in the general case be a routing device with
   multiple interfaces.  Even a device as simple as a wifi access point
   may have wired, and multiple frequencies of wireless interfaces,
   potentially with multiple ESSIDs.

   Each of these interfaces on the Join Proxy may be separate L3 routing
   domains, and therefore will have a unique set of link-local
   addresses.  An IPIP packet being returned by the Registrar needs to
   be forwarded to the correct interface, so the Join Proxy needs an
   additional key to distinguish which network the packet should be
   returned to.

   The simplest way to get this additional key is to allocate an
   additional ACP address; one address for each network on which join
   traffic is occuring.  The Join Proxy SHOULD do a GRASP M_NEG_SYN for
   each interface for which they wish to relay traffic, as this allows
   the Registrar to do any static tunnel configuration that may be
   required.

C.2.  Automatic configuration of tunnels on Registrar

   The Join Proxy is expected to do a GRASP negotiation with the Proxy
   for each Join Interface that it needs to relay traffic from.  This is
   to permit Registrars to configure the appropriate virtual interfaces
   before join traffic arrives.

   A Registrar serving a large number of interfaces may not wish to
   allocate resources to every interface at all times, but can instead
   dynamically allocate interfaces.  It can do this by monitoring IPIP
   traffic that arrives on its ACP interface, and when packets arrive
   from new Join Proxys, it can dynamically configure virtual
   interfaces.

   A more sophisticated Registrar willing to modify the behaviour of its
   TCP and UDP stack could note the IPIP traffic origination in the
   socket control block and make information available to the TCP layer
   (for HTTPS connections), or to the application (for CoAP connections)
   via a proprietary extension to the socket API.

C.3.  Proxy Neighbor Discovery by Join Proxy

   The Join Proxy MUST answer neighbor discovery messages for the
   address given by the Registrar as being its link-local address.  The
   Join Proxy must also advertise this address as the address to which
   to connect when advertising its existence.

   This Proxy neighbor discovery means that the Pledge will create TCP
   and UDP connections to the correct Registrar address.  This matters
   as the TCP and UDP pseudo-header checksum includes the destination
   address, and for the Proxy to remain completely stateless, it must
   not be necessary for the checksum to be updated.

C.4.  Use of connected sockets; or IP_PKTINFO for CoAP on Registrar

   TCP connections on the Registrar SHOULD properly capture the ifindex
   of the incoming connection into the socket structure.  This is normal
   IPv6 socket API processing.  The outgoing responses will go out on
   the same (virtual) interface by ifindex.

   When using UDP sockets with CoAP, the application will have to pay
   attention to the incoming ifindex on the socket.  Access to this
   information is available using the IP_PKTINFO auxiliary extension,
   which is a standard part of the IPv6 sockets API [RFC3542].

   A Registrar application could, after receipt of an initial CoAP
   message from the Pledge, create a connected UDP socket (including the
   ifindex information.)  The kernel would then take care of accurate
   demultiplexing upon receive, and subsequent transmission to the
   correct interface.

C.5.  Use of socket extension rather than virtual interface

   Some operating systems on which a Registrar needs to be implemented
   may find need for a virtual interface per Join Proxy to be
   problematic.  There are other mechanisms which can be implemented.

   If the IPIP decapsulator can mark the (SYN) packet inside the kernel
   with the address of the Join Proxy sending the traffic, then an
   interface per Join Proxy may not be needed.  The outgoing path need
   just pay attention to this extra information and add an appropriate
   IPIP header on outgoing.  A CoAP over UDP mechanism may need to
   expose this extra information to the application as the UDP sockets
   are often not connected, and the application will need to specify the
   outgoing path on each packet sent.

   Such an additional socket mechanism has not been standardized.
   Terminating L2TP connections over IPsec transport mode suffers from
   the same challenges.

Appendix D.  MUD Extension

   The following extension augments the MUD model to include a single
   node, as described in [I-D.ietf-opsawg-mud] 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"
   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>

Appendix E.  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.

E.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.

E.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-----

E.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-----

E.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 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
           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

E.1.4.  Pledge key pair

   The Pledge has an IDevID key pair built in at manufacturing time:

   -----BEGIN EC PRIVATE KEY-----
   MHcCAQEEIL+ue8PQcN+M7LFBGPsompYwobI/rsoHnTb2a+0hO+8joAoGCCqGSM49
   AwEHoUQDQgAEumBVaDlX87WyME8CJToyt9NWy6sYw0DTbjjJIn79pgr7ALa//Y8p
   r70WpK1SIaiUeeFw7e+lCzTp1Z+wJu14Bg==
   -----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.  RFC-EDITOR: Note
   that these certificates are using a Private Enterprise Number for the
   not-yet-assigned by IANA MASA URL, and need to be replaced before
   AUTH48.

   -----BEGIN CERTIFICATE-----
   MIICMjCCAbegAwIBAgIBDDAKBggqhkjOPQQDAjBNMRIwEAYKCZImiZPyLGQBGRYC
   Y2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xHDAaBgNVBAMME1Vuc3RydW5n
   IEhpZ2h3YXkgQ0EwIBcNMTcxMDEyMTM1MjUyWhgPMjk5OTEyMzEwMDAwMDBaMEsx
   EjAQBgoJkiaJk/IsZAEZFgJjYTEZMBcGCgmSJomT8ixkARkWCXNhbmRlbG1hbjEa
   MBgGA1UEAwwRMDAtRDAtRTUtRjItMDAtMDIwWTATBgcqhkjOPQIBBggqhkjOPQMB
   BwNCAARJp5i0dU1aUnR2u8wMRwgkNupNbNM7m1n0mj+0KJZjcPIqID+trPjTSobt
   uIdpRPfGZ8hU/nIUveqwyoYI8BPbo4GHMIGEMB0GA1UdDgQWBBQdMRZhthFQmzz6
   E7YVXzkL7XZDKjAJBgNVHRMEAjAAMCsGA1UdEQQkMCKgIAYJKwYBBAGC7lIBoBMM
   ETAwLUQwLUU1LUYyLTAwLTAyMCsGCSsGAQQBgu5SAgQeDBxodHRwczovL2hpZ2h3
   YXkuc2FuZGVsbWFuLmNhMAoGCCqGSM49BAMCA2kAMGYCMQDhJ1N+eanW1U/e5qoM
   SGvUvWHR7uic8cJbh7vXy580nBs8bpNn60k/+IzvEUetMzICMQCr1uxvdYeKq7mb
   RXCR4ZCJsw67fJ7jyXZbCUSir+3wBT2+lWggzPDRgYB5ABb7sAw=
   -----END CERTIFICATE-----

   The Pledge public certificate as decoded by openssl's x509 utility so
   that the extensions can be seen.  A second custom Extension is
   included to provided to contain the EUI48/EUI64 that the Pledge will
   configure.

   Certificate:
       Data:
           Version: 3 (0x2)
           Serial Number: 12 (0xc)
           Signature Algorithm: ecdsa-with-SHA256
           Issuer: DC = ca, DC = sandelman, CN = Unstrung Highw
   ay CA
           Validity
               Not Before: Oct 12 13:52:52 2017 GMT
               Not After : Dec 31 00:00:00 2999 GMT
           Subject: DC = ca, DC = sandelman, CN = 00-D0-E5-F2-0
   0-02
           Subject Public Key Info:
               Public Key Algorithm: id-ecPublicKey
                   Public-Key: (256 bit)
                   pub:
                       04:49:a7:98:b4:75:4d:5a:52:74:76:bb:cc:0
   c:47:
                       08:24:36:ea:4d:6c:d3:3b:9b:59:f4:9a:3f:b
   4:28:
                       96:63:70:f2:2a:20:3f:ad:ac:f8:d3:4a:86:e
   d:b8:
                       87:69:44:f7:c6:67:c8:54:fe:72:14:bd:ea:b
   0:ca:
                       86:08:f0:13:db
                   ASN1 OID: prime256v1
                   NIST CURVE: P-256
           X509v3 extensions:
               X509v3 Subject Key Identifier:
                   1D:31:16:61:B6:11:50:9B:3C:FA:13:B6:15:5F:39
   :0B:ED:76:43:2A
               X509v3 Basic Constraints:
                   CA:FALSE
               X509v3 Subject Alternative Name:
                   othername:<unsupported>
               1.3.6.1.4.1.46930.2:
                   ..https://highway.sandelman.ca
       Signature Algorithm: ecdsa-with-SHA256
            30:66:02:31:00:e1:27:53:7e:79:a9:d6:d5:4f:de:e6:aa:
   0c:
            48:6b:d4:bd:61:d1:ee:e8:9c:f1:c2:5b:87:bb:d7:cb:9f:
   34:
            9c:1b:3c:6e:93:67:eb:49:3f:f8:8c:ef:11:47:ad:33:32:
   02:
            31:00:ab:d6:ec:6f:75:87:8a:ab:b9:9b:45:70:91:e1:90:
   89:
            b3:0e:bb:7c:9e:e3:c9:76:5b:09:44:a2:af:ed:f0:05:3d:
   be:
            95:68:20:cc:f0:d1:81:80:79:00:16:fb:b0:0c

E.2.  Example process

   RFC-EDITOR: these examples will need to be replaced with CMS versions
   once IANA has assigned the eContentType in [I-D.ietf-anima-voucher].

E.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.

   MIIHHAYJKoZIhvcNAQcCoIIHDTCCBwkCAQExDzANBglghkgBZQMEAgEFADCC
   Aw4GCSqGSIb3DQEHAaCCAv8EggL7eyJpZXRmLXZvdWNoZXItcmVxdWVzdDp2
   b3VjaGVyIjp7ImFzc2VydGlvbiI6InByb3hpbWl0eSIsImNyZWF0ZWQtb24i
   OiIyMDE3LTA5LTAxIiwic2VyaWFsLW51bWJlciI6IjAwLUQwLUU1LUYyLTAw
   LTAyIiwibm9uY2UiOiJEc3M5OXNCcjNwTk1PQUNlLUxZWTd3IiwicHJveGlt
   aXR5LXJlZ2lzdHJhci1jZXJ0IjoiTUlJQnJqQ0NBVE9nQXdJQkFnSUJBekFL
   QmdncWhrak9QUVFEQXpCT01SSXdFQVlLQ1pJbWlaUHlMR1FCR1JZQ1kyRXhH
   VEFYQmdvSmtpYUprL0lzWkFFWkZnbHpZVzVrWld4dFlXNHhIVEFiQmdOVkJB
   TU1GRlZ1YzNSeWRXNW5JRVp2ZFc1MFlXbHVJRU5CTUI0WERURTNNRGt3TlRB
   eE1USTBOVm9YRFRFNU1Ea3dOVEF4TVRJME5Wb3dRekVTTUJBR0NnbVNKb21U
   OGl4a0FSa1dBbU5oTVJrd0Z3WUtDWkltaVpQeUxHUUJHUllKYzJGdVpHVnNi
   V0Z1TVJJd0VBWURWUVFEREFsc2IyTmhiR2h2YzNRd1dUQVRCZ2NxaGtqT1BR
   SUJCZ2dxaGtqT1BRTUJCd05DQUFRMVpBN053MHhTTS9RMnUxOTRGelFNa3Ra
   OTR3YUFJVjBpL29WVFBnT0o4elc2TXdGNXorRHBiOC9wdWhPYkpNWjBVNkgv
   d2ZBcFI2c3ZsdW1kNHJ5eW93MHdDekFKQmdOVkhSTUVBakFBTUFvR0NDcUdT
   TTQ5QkFNREEya0FNR1lDTVFDMy9pVFFKM2V2WVljZ2JYaGJtenJwNjR0M1FD
   NnFqSWVZMmprRHgwNjJudU5pZlZLdHlhYXJhM0YzMEFJa0tTRUNNUURpMjll
   ZmJUTGJkdERrM3RlY1kvckQ3Vjc3WGFKNm5ZQ21kRENSNTRUclNGTkxneHZ0
   MWx5Rk0rMGZZcFlSYzNvPSJ9faCCAjYwggIyMIIBt6ADAgECAgEMMAoGCCqG
   SM49BAMCME0xEjAQBgoJkiaJk/IsZAEZFgJjYTEZMBcGCgmSJomT8ixkARkW
   CXNhbmRlbG1hbjEcMBoGA1UEAwwTVW5zdHJ1bmcgSGlnaHdheSBDQTAgFw0x
   NzEwMTIxMzUyNTJaGA8yOTk5MTIzMTAwMDAwMFowSzESMBAGCgmSJomT8ixk
   ARkWAmNhMRkwFwYKCZImiZPyLGQBGRYJc2FuZGVsbWFuMRowGAYDVQQDDBEw
   MC1EMC1FNS1GMi0wMC0wMjBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABEmn
   mLR1TVpSdHa7zAxHCCQ26k1s0zubWfSaP7QolmNw8iogP62s+NNKhu24h2lE
   98ZnyFT+chS96rDKhgjwE9ujgYcwgYQwHQYDVR0OBBYEFB0xFmG2EVCbPPoT
   thVfOQvtdkMqMAkGA1UdEwQCMAAwKwYDVR0RBCQwIqAgBgkrBgEEAYLuUgGg
   EwwRMDAtRDAtRTUtRjItMDAtMDIwKwYJKwYBBAGC7lICBB4MHGh0dHBzOi8v
   aGlnaHdheS5zYW5kZWxtYW4uY2EwCgYIKoZIzj0EAwIDaQAwZgIxAOEnU355
   qdbVT97mqgxIa9S9YdHu6JzxwluHu9fLnzScGzxuk2frST/4jO8RR60zMgIx
   AKvW7G91h4qruZtFcJHhkImzDrt8nuPJdlsJRKKv7fAFPb6VaCDM8NGBgHkA
   FvuwDDGCAaUwggGhAgEBMFIwTTESMBAGCgmSJomT8ixkARkWAmNhMRkwFwYK
   CZImiZPyLGQBGRYJc2FuZGVsbWFuMRwwGgYDVQQDDBNVbnN0cnVuZyBIaWdo
   d2F5IENBAgEMMA0GCWCGSAFlAwQCAQUAoIHkMBgGCSqGSIb3DQEJAzELBgkq
   hkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTE3MTAxMjE3NTQzMFowLwYJKoZI
   hvcNAQkEMSIEIP59cuKVAPkKOOlQIaIV/W1AsWKbmVmBd9wFSuD5yLafMHkG
   CSqGSIb3DQEJDzFsMGowCwYJYIZIAWUDBAEqMAsGCWCGSAFlAwQBFjALBglg
   hkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3
   DQMCAgFAMAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMAoGCCqGSM49BAMCBEYw
   RAIgYUy0NTdP+xTkm/Et69eI++S/2z3dQwPKOwdL0cDCSvACIAh3jJbybMnK
   cf7DKKnsn2G/O06HeB/8imMI+hnA7CfN

   file: examples/vr_00-D0-E5-F2-00-02.pkcs

   The ASN1 decoding of the artifact:

       0:d=0  hl=4 l=1820 cons: SEQUENCE
       4:d=1  hl=2 l=   9 prim: OBJECT            :pkcs7-signed
   Data
      15:d=1  hl=4 l=1805 cons: cont [ 0 ]
      19:d=2  hl=4 l=1801 cons: SEQUENCE
      23:d=3  hl=2 l=   1 prim: INTEGER           :01
      26:d=3  hl=2 l=  15 cons: SET
      28:d=4  hl=2 l=  13 cons: SEQUENCE
      30:d=5  hl=2 l=   9 prim: OBJECT            :sha256
      41:d=5  hl=2 l=   0 prim: NULL
      43:d=3  hl=4 l= 782 cons: SEQUENCE
      47:d=4  hl=2 l=   9 prim: OBJECT            :pkcs7-data
      58:d=4  hl=4 l= 767 cons: cont [ 0 ]
      62:d=5  hl=4 l= 763 prim: OCTET STRING      :{"ietf-vouch
   er-request:voucher":{"assertion":"proximity","created-on":"2
   017-09-01","serial-number":"00-D0-E5-F2-00-02","nonce":"Dss9
   9sBr3pNMOACe-LYY7w","proximity-registrar-cert":"MIIBrjCCATOg
   AwIBAgIBAzAKBggqhkjOPQQDAzBOMRIwEAYKCZImiZPyLGQBGRYCY2ExGTAX
   BgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xHTAbBgNVBAMMFFVuc3RydW5nIEZv
   dW50YWluIENBMB4XDTE3MDkwNTAxMTI0NVoXDTE5MDkwNTAxMTI0NVowQzES
   MBAGCgmSJomT8ixkARkWAmNhMRkwFwYKCZImiZPyLGQBGRYJc2FuZGVsbWFu
   MRIwEAYDVQQDDAlsb2NhbGhvc3QwWTATBgcqhkjOPQIBBggqhkjOPQMBBwNC
   AAQ1ZA7Nw0xSM/Q2u194FzQMktZ94waAIV0i/oVTPgOJ8zW6MwF5z+Dpb8/p
   uhObJMZ0U6H/wfApR6svlumd4ryyow0wCzAJBgNVHRMEAjAAMAoGCCqGSM49
   BAMDA2kAMGYCMQC3/iTQJ3evYYcgbXhbmzrp64t3QC6qjIeY2jkDx062nuNi
   fVKtyaara3F30AIkKSECMQDi29efbTLbdtDk3tecY/rD7V77XaJ6nYCmdDCR
   54TrSFNLgxvt1lyFM+0fYpYRc3o="}}
     829:d=3  hl=4 l= 566 cons: cont [ 0 ]
     833:d=4  hl=4 l= 562 cons: SEQUENCE
     837:d=5  hl=4 l= 439 cons: SEQUENCE
     841:d=6  hl=2 l=   3 cons: cont [ 0 ]
     843:d=7  hl=2 l=   1 prim: INTEGER           :02
     846:d=6  hl=2 l=   1 prim: INTEGER           :0C
     849:d=6  hl=2 l=  10 cons: SEQUENCE
     851:d=7  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA256
     861:d=6  hl=2 l=  77 cons: SEQUENCE
     863:d=7  hl=2 l=  18 cons: SET
     865:d=8  hl=2 l=  16 cons: SEQUENCE
     867:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
     879:d=9  hl=2 l=   2 prim: IA5STRING         :ca
     883:d=7  hl=2 l=  25 cons: SET
     885:d=8  hl=2 l=  23 cons: SEQUENCE
     887:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
     899:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
     910:d=7  hl=2 l=  28 cons: SET
     912:d=8  hl=2 l=  26 cons: SEQUENCE
     914:d=9  hl=2 l=   3 prim: OBJECT            :commonName
     919:d=9  hl=2 l=  19 prim: UTF8STRING        :Unstrung Hig
   hway CA
     940:d=6  hl=2 l=  32 cons: SEQUENCE
     942:d=7  hl=2 l=  13 prim: UTCTIME           :171012135252
   Z
     957:d=7  hl=2 l=  15 prim: GENERALIZEDTIME   :299912310000
   00Z
     974:d=6  hl=2 l=  75 cons: SEQUENCE
     976:d=7  hl=2 l=  18 cons: SET
     978:d=8  hl=2 l=  16 cons: SEQUENCE
     980:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
     992:d=9  hl=2 l=   2 prim: IA5STRING         :ca
     996:d=7  hl=2 l=  25 cons: SET
     998:d=8  hl=2 l=  23 cons: SEQUENCE
    1000:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    1012:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
    1023:d=7  hl=2 l=  26 cons: SET
    1025:d=8  hl=2 l=  24 cons: SEQUENCE
    1027:d=9  hl=2 l=   3 prim: OBJECT            :commonName
    1032:d=9  hl=2 l=  17 prim: UTF8STRING        :00-D0-E5-F2-
   00-02
    1051:d=6  hl=2 l=  89 cons: SEQUENCE
    1053:d=7  hl=2 l=  19 cons: SEQUENCE
    1055:d=8  hl=2 l=   7 prim: OBJECT            :id-ecPublicK
   ey
    1064:d=8  hl=2 l=   8 prim: OBJECT            :prime256v1
    1074:d=7  hl=2 l=  66 prim: BIT STRING
    1142:d=6  hl=3 l= 135 cons: cont [ 3 ]
    1145:d=7  hl=3 l= 132 cons: SEQUENCE
    1148:d=8  hl=2 l=  29 cons: SEQUENCE
    1150:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Subje
   ct Key Identifier
    1155:d=9  hl=2 l=  22 prim: OCTET STRING      [HEX DUMP]:04
   141D311661B611509B3CFA13B6155F390BED76432A
    1179:d=8  hl=2 l=   9 cons: SEQUENCE
    1181:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Basic
    Constraints
    1186:d=9  hl=2 l=   2 prim: OCTET STRING      [HEX DUMP]:30
   00
    1190:d=8  hl=2 l=  43 cons: SEQUENCE
    1192:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Subje
   ct Alternative Name
    1197:d=9  hl=2 l=  36 prim: OCTET STRING      [HEX DUMP]:30
   22A02006092B0601040182EE5201A0130C1130302D44302D45352D46322D
   30302D3032
    1235:d=8  hl=2 l=  43 cons: SEQUENCE
    1237:d=9  hl=2 l=   9 prim: OBJECT            :1.3.6.1.4.1.
   46930.2
    1248:d=9  hl=2 l=  30 prim: OCTET STRING      [HEX DUMP]:0C
   1C68747470733A2F2F686967687761792E73616E64656C6D616E2E6361
    1280:d=5  hl=2 l=  10 cons: SEQUENCE
    1282:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA256
    1292:d=5  hl=2 l= 105 prim: BIT STRING
    1399:d=3  hl=4 l= 421 cons: SET
    1403:d=4  hl=4 l= 417 cons: SEQUENCE
    1407:d=5  hl=2 l=   1 prim: INTEGER           :01
    1410:d=5  hl=2 l=  82 cons: SEQUENCE
    1412:d=6  hl=2 l=  77 cons: SEQUENCE
    1414:d=7  hl=2 l=  18 cons: SET
    1416:d=8  hl=2 l=  16 cons: SEQUENCE
    1418:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    1430:d=9  hl=2 l=   2 prim: IA5STRING         :ca
    1434:d=7  hl=2 l=  25 cons: SET
    1436:d=8  hl=2 l=  23 cons: SEQUENCE
    1438:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    1450:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
    1461:d=7  hl=2 l=  28 cons: SET
    1463:d=8  hl=2 l=  26 cons: SEQUENCE
    1465:d=9  hl=2 l=   3 prim: OBJECT            :commonName
    1470:d=9  hl=2 l=  19 prim: UTF8STRING        :Unstrung Hig
   hway CA
    1491:d=6  hl=2 l=   1 prim: INTEGER           :0C
    1494:d=5  hl=2 l=  13 cons: SEQUENCE
    1496:d=6  hl=2 l=   9 prim: OBJECT            :sha256
    1507:d=6  hl=2 l=   0 prim: NULL
    1509:d=5  hl=3 l= 228 cons: cont [ 0 ]
    1512:d=6  hl=2 l=  24 cons: SEQUENCE
    1514:d=7  hl=2 l=   9 prim: OBJECT            :contentType
    1525:d=7  hl=2 l=  11 cons: SET
    1527:d=8  hl=2 l=   9 prim: OBJECT            :pkcs7-data
    1538:d=6  hl=2 l=  28 cons: SEQUENCE
    1540:d=7  hl=2 l=   9 prim: OBJECT            :signingTime
    1551:d=7  hl=2 l=  15 cons: SET
    1553:d=8  hl=2 l=  13 prim: UTCTIME           :171012175430
   Z
    1568:d=6  hl=2 l=  47 cons: SEQUENCE
    1570:d=7  hl=2 l=   9 prim: OBJECT            :messageDiges
   t
    1581:d=7  hl=2 l=  34 cons: SET
    1583:d=8  hl=2 l=  32 prim: OCTET STRING      [HEX DUMP]:FE
   7D72E29500F90A38E95021A215FD6D40B1629B99598177DC054AE0F9C8B6
   9F
    1617:d=6  hl=2 l= 121 cons: SEQUENCE
    1619:d=7  hl=2 l=   9 prim: OBJECT            :S/MIME Capab
   ilities
    1630:d=7  hl=2 l= 108 cons: SET
    1632:d=8  hl=2 l= 106 cons: SEQUENCE
    1634:d=9  hl=2 l=  11 cons: SEQUENCE
    1636:d=10 hl=2 l=   9 prim: OBJECT            :aes-256-cbc
    1647:d=9  hl=2 l=  11 cons: SEQUENCE
    1649:d=10 hl=2 l=   9 prim: OBJECT            :aes-192-cbc
    1660:d=9  hl=2 l=  11 cons: SEQUENCE
    1662:d=10 hl=2 l=   9 prim: OBJECT            :aes-128-cbc
    1673:d=9  hl=2 l=  10 cons: SEQUENCE
    1675:d=10 hl=2 l=   8 prim: OBJECT            :des-ede3-cbc
    1685:d=9  hl=2 l=  14 cons: SEQUENCE
    1687:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    1697:d=10 hl=2 l=   2 prim: INTEGER           :80
    1701:d=9  hl=2 l=  13 cons: SEQUENCE
    1703:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    1713:d=10 hl=2 l=   1 prim: INTEGER           :40
    1716:d=9  hl=2 l=   7 cons: SEQUENCE
    1718:d=10 hl=2 l=   5 prim: OBJECT            :des-cbc
    1725:d=9  hl=2 l=  13 cons: SEQUENCE
    1727:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    1737:d=10 hl=2 l=   1 prim: INTEGER           :28
    1740:d=5  hl=2 l=  10 cons: SEQUENCE
    1742:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA256
    1752:d=5  hl=2 l=  70 prim: OCTET STRING      [HEX DUMP]:30
   440220614CB435374FFB14E49BF12DEBD788FBE4BFDB3DDD4303CA3B074B
   D1C0C24AF0022008778C96F26CC9CA71FEC328A9EC9F61BF3B4E87781FFC
   8A6308FA19C0EC27CD

   The JSON contained in the voucher request:

   {"ietf-voucher-request:voucher":{"assertion":"proximity","cr
   eated-on":"2017-09-01","serial-number":"00-D0-E5-F2-00-02","
   nonce":"Dss99sBr3pNMOACe-LYY7w","proximity-registrar-cert":"
   MIIBrjCCATOgAwIBAgIBAzAKBggqhkjOPQQDAzBOMRIwEAYKCZImiZPyLGQB
   GRYCY2ExGTAXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xHTAbBgNVBAMMFFVu
   c3RydW5nIEZvdW50YWluIENBMB4XDTE3MDkwNTAxMTI0NVoXDTE5MDkwNTAx
   MTI0NVowQzESMBAGCgmSJomT8ixkARkWAmNhMRkwFwYKCZImiZPyLGQBGRYJ
   c2FuZGVsbWFuMRIwEAYDVQQDDAlsb2NhbGhvc3QwWTATBgcqhkjOPQIBBggq
   hkjOPQMBBwNCAAQ1ZA7Nw0xSM/Q2u194FzQMktZ94waAIV0i/oVTPgOJ8zW6
   MwF5z+Dpb8/puhObJMZ0U6H/wfApR6svlumd4ryyow0wCzAJBgNVHRMEAjAA
   MAoGCCqGSM49BAMDA2kAMGYCMQC3/iTQJ3evYYcgbXhbmzrp64t3QC6qjIeY
   2jkDx062nuNifVKtyaara3F30AIkKSECMQDi29efbTLbdtDk3tecY/rD7V77
   XaJ6nYCmdDCR54TrSFNLgxvt1lyFM+0fYpYRc3o="}}

E.2.2.  Registrar to MASA

   As described in Section 5.4 the Registrar will sign a Registrar
   voucher-request, and will include Pledge's voucher request in the
   prior-signed-voucher-request.

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   OsxlACaW/HenAqNwMHkGCSqGSIb3DQEJDzFsMGowCwYJYIZIAWUDBAEqMAsG
   CWCGSAFlAwQBFjALBglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcN
   AwICAgCAMA0GCCqGSIb3DQMCAgFAMAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEo
   MAoGCCqGSM49BAMCBEcwRQIgDdp5uPUlMKp7GFQAD7ypAgqFv8q+KkJt6c3O
   7iVpVI8CIQCD1u8BkxipvigwvIDmWfjlYdJxcvozNjffq5j3UHg7Rg==

   file: examples/parboiled_vr_00-D0-E5-F2-00-02.pkcs

   The ASN1 decoding of the artifact:

       0:d=0  hl=4 l=3546 cons: SEQUENCE
       4:d=1  hl=2 l=   9 prim: OBJECT            :pkcs7-signed
   Data
      15:d=1  hl=4 l=3531 cons: cont [ 0 ]
      19:d=2  hl=4 l=3527 cons: SEQUENCE
      23:d=3  hl=2 l=   1 prim: INTEGER           :01
      26:d=3  hl=2 l=  15 cons: SET
      28:d=4  hl=2 l=  13 cons: SEQUENCE
      30:d=5  hl=2 l=   9 prim: OBJECT            :sha256
      41:d=5  hl=2 l=   0 prim: NULL
      43:d=3  hl=4 l=2638 cons: SEQUENCE
      47:d=4  hl=2 l=   9 prim: OBJECT            :pkcs7-data
      58:d=4  hl=4 l=2623 cons: cont [ 0 ]
      62:d=5  hl=4 l=2619 prim: OCTET STRING      :{"ietf-vouch
   er-request:voucher":{"assertion":"proximity","created-on":"2
   017-09-15T00:00:00.000Z","serial-number":"JADA123456789","no
   nce":"abcd1234","prior-signed-voucher-request":"MIIHHQYJKoZI
   hvcNAQcCoIIHDjCCBwoCAQExDzANBglghkgBZQMEAgEFADCCAw4GCSqGSIb3
   DQEHAaCCAv8EggL7eyJpZXRmLXZvdWNoZXItcmVxdWVzdDp2b3VjaGVyIjp7
   ImFzc2VydGlvbiI6InByb3hpbWl0eSIsImNyZWF0ZWQtb24iOiIyMDE3LTA5
   LTAxIiwic2VyaWFsLW51bWJlciI6IjAwLUQwLUU1LUYyLTAwLTAyIiwibm9u
   Y2UiOiJEc3M5OXNCcjNwTk1PQUNlLUxZWTd3IiwicHJveGltaXR5LXJlZ2lz
   dHJhci1jZXJ0IjoiTUlJQnJqQ0NBVE9nQXdJQkFnSUJBekFLQmdncWhrak9Q
   UVFEQXpCT01SSXdFQVlLQ1pJbWlaUHlMR1FCR1JZQ1kyRXhHVEFYQmdvSmtp
   YUprL0lzWkFFWkZnbHpZVzVrWld4dFlXNHhIVEFiQmdOVkJBTU1GRlZ1YzNS
   eWRXNW5JRVp2ZFc1MFlXbHVJRU5CTUI0WERURTNNRGt3TlRBeE1USTBOVm9Y
   RFRFNU1Ea3dOVEF4TVRJME5Wb3dRekVTTUJBR0NnbVNKb21UOGl4a0FSa1dB
   bU5oTVJrd0Z3WUtDWkltaVpQeUxHUUJHUllKYzJGdVpHVnNiV0Z1TVJJd0VB
   WURWUVFEREFsc2IyTmhiR2h2YzNRd1dUQVRCZ2NxaGtqT1BRSUJCZ2dxaGtq
   T1BRTUJCd05DQUFRMVpBN053MHhTTS9RMnUxOTRGelFNa3RaOTR3YUFJVjBp
   L29WVFBnT0o4elc2TXdGNXorRHBiOC9wdWhPYkpNWjBVNkgvd2ZBcFI2c3Zs
   dW1kNHJ5eW93MHdDekFKQmdOVkhSTUVBakFBTUFvR0NDcUdTTTQ5QkFNREEy
   a0FNR1lDTVFDMy9pVFFKM2V2WVljZ2JYaGJtenJwNjR0M1FDNnFqSWVZMmpr
   RHgwNjJudU5pZlZLdHlhYXJhM0YzMEFJa0tTRUNNUURpMjllZmJUTGJkdERr
   M3RlY1kvckQ3Vjc3WGFKNm5ZQ21kRENSNTRUclNGTkxneHZ0MWx5Rk0rMGZZ
   cFlSYzNvPSJ9faCCAjYwggIyMIIBt6ADAgECAgEMMAoGCCqGSM49BAMCME0x
   EjAQBgoJkiaJk/IsZAEZFgJjYTEZMBcGCgmSJomT8ixkARkWCXNhbmRlbG1h
   bjEcMBoGA1UEAwwTVW5zdHJ1bmcgSGlnaHdheSBDQTAgFw0xNzEwMTIxMzUy
   NTJaGA8yOTk5MTIzMTAwMDAwMFowSzESMBAGCgmSJomT8ixkARkWAmNhMRkw
   FwYKCZImiZPyLGQBGRYJc2FuZGVsbWFuMRowGAYDVQQDDBEwMC1EMC1FNS1G
   Mi0wMC0wMjBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABEmnmLR1TVpSdHa7
   zAxHCCQ26k1s0zubWfSaP7QolmNw8iogP62s+NNKhu24h2lE98ZnyFT+chS9
   6rDKhgjwE9ujgYcwgYQwHQYDVR0OBBYEFB0xFmG2EVCbPPoTthVfOQvtdkMq
   MAkGA1UdEwQCMAAwKwYDVR0RBCQwIqAgBgkrBgEEAYLuUgGgEwwRMDAtRDAt
   RTUtRjItMDAtMDIwKwYJKwYBBAGC7lICBB4MHGh0dHBzOi8vaGlnaHdheS5z
   YW5kZWxtYW4uY2EwCgYIKoZIzj0EAwIDaQAwZgIxAOEnU355qdbVT97mqgxI
   a9S9YdHu6JzxwluHu9fLnzScGzxuk2frST/4jO8RR60zMgIxAKvW7G91h4qr
   uZtFcJHhkImzDrt8nuPJdlsJRKKv7fAFPb6VaCDM8NGBgHkAFvuwDDGCAaYw
   ggGiAgEBMFIwTTESMBAGCgmSJomT8ixkARkWAmNhMRkwFwYKCZImiZPyLGQB
   GRYJc2FuZGVsbWFuMRwwGgYDVQQDDBNVbnN0cnVuZyBIaWdod2F5IENBAgEM
   MA0GCWCGSAFlAwQCAQUAoIHkMBgGCSqGSIb3DQEJAzELBgkqhkiG9w0BBwEw
   HAYJKoZIhvcNAQkFMQ8XDTE3MTAxMjEzNTgyM1owLwYJKoZIhvcNAQkEMSIE
   IP59cuKVAPkKOOlQIaIV/W1AsWKbmVmBd9wFSuD5yLafMHkGCSqGSIb3DQEJ
   DzFsMGowCwYJYIZIAWUDBAEqMAsGCWCGSAFlAwQBFjALBglghkgBZQMEAQIw
   CgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFAMAcG
   BSsOAwIHMA0GCCqGSIb3DQMCAgEoMAoGCCqGSM49BAMCBEcwRQIgEMg1dJL7
   FcdtrVDx8qCazoe9+22Nz4ZwRB9gATGL7MMCIQDjssUlZzJqp2/kCd4WhxUh
   saCpTFwPrnNew5wCkYUF8Q=="}}
    2685:d=3  hl=4 l= 434 cons: cont [ 0 ]
    2689:d=4  hl=4 l= 430 cons: SEQUENCE
    2693:d=5  hl=4 l= 307 cons: SEQUENCE
    2697:d=6  hl=2 l=   3 cons: cont [ 0 ]
    2699:d=7  hl=2 l=   1 prim: INTEGER           :02
    2702:d=6  hl=2 l=   1 prim: INTEGER           :03
    2705:d=6  hl=2 l=  10 cons: SEQUENCE
    2707:d=7  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA384
    2717:d=6  hl=2 l=  78 cons: SEQUENCE
    2719:d=7  hl=2 l=  18 cons: SET
    2721:d=8  hl=2 l=  16 cons: SEQUENCE
    2723:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    2735:d=9  hl=2 l=   2 prim: IA5STRING         :ca
    2739:d=7  hl=2 l=  25 cons: SET
    2741:d=8  hl=2 l=  23 cons: SEQUENCE
    2743:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    2755:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
    2766:d=7  hl=2 l=  29 cons: SET
    2768:d=8  hl=2 l=  27 cons: SEQUENCE
    2770:d=9  hl=2 l=   3 prim: OBJECT            :commonName
    2775:d=9  hl=2 l=  20 prim: UTF8STRING        :Unstrung Fou
   ntain CA
    2797:d=6  hl=2 l=  30 cons: SEQUENCE
    2799:d=7  hl=2 l=  13 prim: UTCTIME           :170905011245
   Z
    2814:d=7  hl=2 l=  13 prim: UTCTIME           :190905011245
   Z
    2829:d=6  hl=2 l=  67 cons: SEQUENCE
    2831:d=7  hl=2 l=  18 cons: SET
    2833:d=8  hl=2 l=  16 cons: SEQUENCE
    2835:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    2847:d=9  hl=2 l=   2 prim: IA5STRING         :ca
    2851:d=7  hl=2 l=  25 cons: SET
    2853:d=8  hl=2 l=  23 cons: SEQUENCE
    2855:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    2867:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
    2878:d=7  hl=2 l=  18 cons: SET
    2880:d=8  hl=2 l=  16 cons: SEQUENCE
    2882:d=9  hl=2 l=   3 prim: OBJECT            :commonName
    2887:d=9  hl=2 l=   9 prim: UTF8STRING        :localhost
    2898:d=6  hl=2 l=  89 cons: SEQUENCE
    2900:d=7  hl=2 l=  19 cons: SEQUENCE
    2902:d=8  hl=2 l=   7 prim: OBJECT            :id-ecPublicK
   ey
    2911:d=8  hl=2 l=   8 prim: OBJECT            :prime256v1
    2921:d=7  hl=2 l=  66 prim: BIT STRING
    2989:d=6  hl=2 l=  13 cons: cont [ 3 ]
    2991:d=7  hl=2 l=  11 cons: SEQUENCE
    2993:d=8  hl=2 l=   9 cons: SEQUENCE
    2995:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Basic
    Constraints
    3000:d=9  hl=2 l=   2 prim: OCTET STRING      [HEX DUMP]:30
   00
    3004:d=5  hl=2 l=  10 cons: SEQUENCE
    3006:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA384
    3016:d=5  hl=2 l= 105 prim: BIT STRING
    3123:d=3  hl=4 l= 423 cons: SET
    3127:d=4  hl=4 l= 419 cons: SEQUENCE
    3131:d=5  hl=2 l=   1 prim: INTEGER           :01
    3134:d=5  hl=2 l=  83 cons: SEQUENCE
    3136:d=6  hl=2 l=  78 cons: SEQUENCE
    3138:d=7  hl=2 l=  18 cons: SET
    3140:d=8  hl=2 l=  16 cons: SEQUENCE
    3142:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    3154:d=9  hl=2 l=   2 prim: IA5STRING         :ca
    3158:d=7  hl=2 l=  25 cons: SET
    3160:d=8  hl=2 l=  23 cons: SEQUENCE
    3162:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    3174:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
    3185:d=7  hl=2 l=  29 cons: SET
    3187:d=8  hl=2 l=  27 cons: SEQUENCE
    3189:d=9  hl=2 l=   3 prim: OBJECT            :commonName
    3194:d=9  hl=2 l=  20 prim: UTF8STRING        :Unstrung Fou
   ntain CA
    3216:d=6  hl=2 l=   1 prim: INTEGER           :03
    3219:d=5  hl=2 l=  13 cons: SEQUENCE
    3221:d=6  hl=2 l=   9 prim: OBJECT            :sha256
    3232:d=6  hl=2 l=   0 prim: NULL
    3234:d=5  hl=3 l= 228 cons: cont [ 0 ]
    3237:d=6  hl=2 l=  24 cons: SEQUENCE
    3239:d=7  hl=2 l=   9 prim: OBJECT            :contentType
    3250:d=7  hl=2 l=  11 cons: SET
    3252:d=8  hl=2 l=   9 prim: OBJECT            :pkcs7-data
    3263:d=6  hl=2 l=  28 cons: SEQUENCE
    3265:d=7  hl=2 l=   9 prim: OBJECT            :signingTime
    3276:d=7  hl=2 l=  15 cons: SET
    3278:d=8  hl=2 l=  13 prim: UTCTIME           :171026013618
   Z
    3293:d=6  hl=2 l=  47 cons: SEQUENCE
    3295:d=7  hl=2 l=   9 prim: OBJECT            :messageDiges
   t
    3306:d=7  hl=2 l=  34 cons: SET
    3308:d=8  hl=2 l=  32 prim: OCTET STRING      [HEX DUMP]:44
   0133BDCF6733E8EED13D323F2042F69A61E3103ACC65002696FC77A702A3
   70
    3342:d=6  hl=2 l= 121 cons: SEQUENCE
    3344:d=7  hl=2 l=   9 prim: OBJECT            :S/MIME Capab
   ilities
    3355:d=7  hl=2 l= 108 cons: SET
    3357:d=8  hl=2 l= 106 cons: SEQUENCE
    3359:d=9  hl=2 l=  11 cons: SEQUENCE
    3361:d=10 hl=2 l=   9 prim: OBJECT            :aes-256-cbc
    3372:d=9  hl=2 l=  11 cons: SEQUENCE
    3374:d=10 hl=2 l=   9 prim: OBJECT            :aes-192-cbc
    3385:d=9  hl=2 l=  11 cons: SEQUENCE
    3387:d=10 hl=2 l=   9 prim: OBJECT            :aes-128-cbc
    3398:d=9  hl=2 l=  10 cons: SEQUENCE
    3400:d=10 hl=2 l=   8 prim: OBJECT            :des-ede3-cbc
    3410:d=9  hl=2 l=  14 cons: SEQUENCE
    3412:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    3422:d=10 hl=2 l=   2 prim: INTEGER           :80
    3426:d=9  hl=2 l=  13 cons: SEQUENCE
    3428:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    3438:d=10 hl=2 l=   1 prim: INTEGER           :40
    3441:d=9  hl=2 l=   7 cons: SEQUENCE
    3443:d=10 hl=2 l=   5 prim: OBJECT            :des-cbc
    3450:d=9  hl=2 l=  13 cons: SEQUENCE
    3452:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    3462:d=10 hl=2 l=   1 prim: INTEGER           :28
    3465:d=5  hl=2 l=  10 cons: SEQUENCE
    3467:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA256
    3477:d=5  hl=2 l=  71 prim: OCTET STRING      [HEX DUMP]:30
   4502200DDA79B8F52530AA7B1854000FBCA9020A85BFCABE2A426DE9CDCE
   EE2569548F02210083D6EF019318A9BE2830BC80E659F8E561D27172FA33
   3637DFAB98F750783B46

E.2.3.  MASA to Registrar

   The MASA will return a voucher to the Registrar, to be relayed to the
   Pledge.

   MIIG3AYJKoZIhvcNAQcCoIIGzTCCBskCAQExDzANBglghkgBZQMEAgEFADCC
   AxAGCSqGSIb3DQEHAaCCAwEEggL9eyJpZXRmLXZvdWNoZXI6dm91Y2hlciI6
   eyJhc3NlcnRpb24iOiJsb2dnZWQiLCJjcmVhdGVkLW9uIjoiMjAxNy0xMC0x
   MlQxMzo1NDozMS40MzktMDQ6MDAiLCJzZXJpYWwtbnVtYmVyIjoiMDAtRDAt
   RTUtRjItMDAtMDIiLCJub25jZSI6IkRzczk5c0JyM3BOTU9BQ2UtTFlZN3ci
   LCJwaW5uZWQtZG9tYWluLWNlcnQiOiJNSUlCcmpDQ0FUT2dBd0lCQWdJQkF6
   QUtCZ2dxaGtqT1BRUURBekJPTVJJd0VBWUtDWkltaVpQeUxHUUJHUllDWTJF
   eEdUQVhCZ29Ka2lhSmsvSXNaQUVaRmdsellXNWtaV3h0WVc0eEhUQWJCZ05W
   QkFNTUZGVnVjM1J5ZFc1bklFWnZkVzUwWVdsdUlFTkJNQjRYRFRFM01Ea3dO
   VEF4TVRJME5Wb1hEVEU1TURrd05UQXhNVEkwTlZvd1F6RVNNQkFHQ2dtU0pv
   bVQ4aXhrQVJrV0FtTmhNUmt3RndZS0NaSW1pWlB5TEdRQkdSWUpjMkZ1WkdW
   c2JXRnVNUkl3RUFZRFZRUUREQWxzYjJOaGJHaHZjM1F3V1RBVEJnY3Foa2pP
   UFFJQkJnZ3Foa2pPUFFNQkJ3TkNBQVExWkE3TncweFNNL1EydTE5NEZ6UU1r
   dFo5NHdhQUlWMGkvb1ZUUGdPSjh6VzZNd0Y1eitEcGI4L3B1aE9iSk1aMFU2
   SC93ZkFwUjZzdmx1bWQ0cnl5b3cwd0N6QUpCZ05WSFJNRUFqQUFNQW9HQ0Nx
   R1NNNDlCQU1EQTJrQU1HWUNNUUMzL2lUUUozZXZZWWNnYlhoYm16cnA2NHQz
   UUM2cWpJZVkyamtEeDA2Mm51TmlmVkt0eWFhcmEzRjMwQUlrS1NFQ01RRGky
   OWVmYlRMYmR0RGszdGVjWS9yRDdWNzdYYUo2bllDbWREQ1I1NFRyU0ZOTGd4
   dnQxbHlGTSswZllwWVJjM289In19oIIB0zCCAc8wggFWoAMCAQICAQEwCgYI
   KoZIzj0EAwIwTTESMBAGCgmSJomT8ixkARkWAmNhMRkwFwYKCZImiZPyLGQB
   GRYJc2FuZGVsbWFuMRwwGgYDVQQDDBNVbnN0cnVuZyBIaWdod2F5IENBMB4X
   DTE3MDMyNjE2MTk0MFoXDTE5MDMyNjE2MTk0MFowRzESMBAGCgmSJomT8ixk
   ARkWAmNhMRkwFwYKCZImiZPyLGQBGRYJc2FuZGVsbWFuMRYwFAYDVQQDDA1V
   bnN0cnVuZyBNQVNBMHYwEAYHKoZIzj0CAQYFK4EEACIDYgAE2QB90W9hbyCT
   p7bPr17llt+aH8jWwh84wMzotpFmRRNQcrqyiJjXDTBRoqxp0VyFxqlgn8OS
   AoCfArjN71ebcvW3+ylJTpHo8077/uT1fvnpZD/R0PN76kwMLNlsFk8SoxAw
   DjAMBgNVHRMBAf8EAjAAMAoGCCqGSM49BAMCA2cAMGQCMBm9KMjNHaD+rd/y
   0jy+Tg7mrRMDGIe1hjviGExwvCuxMhwTpgmEXik9vhoVfwi1swIwTculDCU7
   dbbMSbCanTD1CBY/uMGYNQDiG/yaAOjO6996cC0E6x0cRM1TBn1jpGFMMYIB
   xjCCAcICAQEwUjBNMRIwEAYKCZImiZPyLGQBGRYCY2ExGTAXBgoJkiaJk/Is
   ZAEZFglzYW5kZWxtYW4xHDAaBgNVBAMME1Vuc3RydW5nIEhpZ2h3YXkgQ0EC
   AQEwDQYJYIZIAWUDBAIBBQCggeQwGAYJKoZIhvcNAQkDMQsGCSqGSIb3DQEH
   ATAcBgkqhkiG9w0BCQUxDxcNMTcxMDEyMTc1NDMxWjAvBgkqhkiG9w0BCQQx
   IgQgQXnG628cIW8MoYfB1ljDDlLlJQlxED2tnjcvkLEfix0weQYJKoZIhvcN
   AQkPMWwwajALBglghkgBZQMEASowCwYJYIZIAWUDBAEWMAsGCWCGSAFlAwQB
   AjAKBggqhkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcNAwICAUAw
   BwYFKw4DAgcwDQYIKoZIhvcNAwICASgwCgYIKoZIzj0EAwIEZzBlAjEAhzid
   /AkNjttpSP1rflNppdHsi324Z2+TXJxueewnJ8z/2NXb+Tf3DsThv7du00Oz
   AjBjyOnmkkSKHsPR2JluA5c6wovuPEnNKP32daGGeFKGEHMkTInbrqipC881
   /5K9Q+k=

   file: examples/voucher_00-D0-E5-F2-00-02.pkcs

   The ASN1 decoding of the artifact:

       0:d=0  hl=4 l=1756 cons: SEQUENCE
       4:d=1  hl=2 l=   9 prim: OBJECT            :pkcs7-signed
   Data
      15:d=1  hl=4 l=1741 cons: cont [ 0 ]
      19:d=2  hl=4 l=1737 cons: SEQUENCE
      23:d=3  hl=2 l=   1 prim: INTEGER           :01
      26:d=3  hl=2 l=  15 cons: SET
      28:d=4  hl=2 l=  13 cons: SEQUENCE
      30:d=5  hl=2 l=   9 prim: OBJECT            :sha256
      41:d=5  hl=2 l=   0 prim: NULL
      43:d=3  hl=4 l= 784 cons: SEQUENCE
      47:d=4  hl=2 l=   9 prim: OBJECT            :pkcs7-data
      58:d=4  hl=4 l= 769 cons: cont [ 0 ]
      62:d=5  hl=4 l= 765 prim: OCTET STRING      :{"ietf-vouch
   er:voucher":{"assertion":"logged","created-on":"2017-10-12T1
   3:54:31.439-04:00","serial-number":"00-D0-E5-F2-00-02","nonc
   e":"Dss99sBr3pNMOACe-LYY7w","pinned-domain-cert":"MIIBrjCCAT
   OgAwIBAgIBAzAKBggqhkjOPQQDAzBOMRIwEAYKCZImiZPyLGQBGRYCY2ExGT
   AXBgoJkiaJk/IsZAEZFglzYW5kZWxtYW4xHTAbBgNVBAMMFFVuc3RydW5nIE
   ZvdW50YWluIENBMB4XDTE3MDkwNTAxMTI0NVoXDTE5MDkwNTAxMTI0NVowQz
   ESMBAGCgmSJomT8ixkARkWAmNhMRkwFwYKCZImiZPyLGQBGRYJc2FuZGVsbW
   FuMRIwEAYDVQQDDAlsb2NhbGhvc3QwWTATBgcqhkjOPQIBBggqhkjOPQMBBw
   NCAAQ1ZA7Nw0xSM/Q2u194FzQMktZ94waAIV0i/oVTPgOJ8zW6MwF5z+Dpb8
   /puhObJMZ0U6H/wfApR6svlumd4ryyow0wCzAJBgNVHRMEAjAAMAoGCCqGSM
   49BAMDA2kAMGYCMQC3/iTQJ3evYYcgbXhbmzrp64t3QC6qjIeY2jkDx062nu
   NifVKtyaara3F30AIkKSECMQDi29efbTLbdtDk3tecY/rD7V77XaJ6nYCmdD
   CR54TrSFNLgxvt1lyFM+0fYpYRc3o="}}
     831:d=3  hl=4 l= 467 cons: cont [ 0 ]
     835:d=4  hl=4 l= 463 cons: SEQUENCE
     839:d=5  hl=4 l= 342 cons: SEQUENCE
     843:d=6  hl=2 l=   3 cons: cont [ 0 ]
     845:d=7  hl=2 l=   1 prim: INTEGER           :02
     848:d=6  hl=2 l=   1 prim: INTEGER           :01
     851:d=6  hl=2 l=  10 cons: SEQUENCE
     853:d=7  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA256
     863:d=6  hl=2 l=  77 cons: SEQUENCE
     865:d=7  hl=2 l=  18 cons: SET
     867:d=8  hl=2 l=  16 cons: SEQUENCE
     869:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
     881:d=9  hl=2 l=   2 prim: IA5STRING         :ca
     885:d=7  hl=2 l=  25 cons: SET
     887:d=8  hl=2 l=  23 cons: SEQUENCE
     889:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
     901:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
     912:d=7  hl=2 l=  28 cons: SET
     914:d=8  hl=2 l=  26 cons: SEQUENCE
     916:d=9  hl=2 l=   3 prim: OBJECT            :commonName
     921:d=9  hl=2 l=  19 prim: UTF8STRING        :Unstrung Hig

   hway CA
     942:d=6  hl=2 l=  30 cons: SEQUENCE
     944:d=7  hl=2 l=  13 prim: UTCTIME           :170326161940
   Z
     959:d=7  hl=2 l=  13 prim: UTCTIME           :190326161940
   Z
     974:d=6  hl=2 l=  71 cons: SEQUENCE
     976:d=7  hl=2 l=  18 cons: SET
     978:d=8  hl=2 l=  16 cons: SEQUENCE
     980:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
     992:d=9  hl=2 l=   2 prim: IA5STRING         :ca
     996:d=7  hl=2 l=  25 cons: SET
     998:d=8  hl=2 l=  23 cons: SEQUENCE
    1000:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    1012:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
    1023:d=7  hl=2 l=  22 cons: SET
    1025:d=8  hl=2 l=  20 cons: SEQUENCE
    1027:d=9  hl=2 l=   3 prim: OBJECT            :commonName
    1032:d=9  hl=2 l=  13 prim: UTF8STRING        :Unstrung MAS
   A
    1047:d=6  hl=2 l= 118 cons: SEQUENCE
    1049:d=7  hl=2 l=  16 cons: SEQUENCE
    1051:d=8  hl=2 l=   7 prim: OBJECT            :id-ecPublicK
   ey
    1060:d=8  hl=2 l=   5 prim: OBJECT            :secp384r1
    1067:d=7  hl=2 l=  98 prim: BIT STRING
    1167:d=6  hl=2 l=  16 cons: cont [ 3 ]
    1169:d=7  hl=2 l=  14 cons: SEQUENCE
    1171:d=8  hl=2 l=  12 cons: SEQUENCE
    1173:d=9  hl=2 l=   3 prim: OBJECT            :X509v3 Basic
    Constraints
    1178:d=9  hl=2 l=   1 prim: BOOLEAN           :255
    1181:d=9  hl=2 l=   2 prim: OCTET STRING      [HEX DUMP]:30
   00
    1185:d=5  hl=2 l=  10 cons: SEQUENCE
    1187:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA256
    1197:d=5  hl=2 l= 103 prim: BIT STRING
    1302:d=3  hl=4 l= 454 cons: SET
    1306:d=4  hl=4 l= 450 cons: SEQUENCE
    1310:d=5  hl=2 l=   1 prim: INTEGER           :01
    1313:d=5  hl=2 l=  82 cons: SEQUENCE
    1315:d=6  hl=2 l=  77 cons: SEQUENCE
    1317:d=7  hl=2 l=  18 cons: SET
    1319:d=8  hl=2 l=  16 cons: SEQUENCE
    1321:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon

   ent
    1333:d=9  hl=2 l=   2 prim: IA5STRING         :ca
    1337:d=7  hl=2 l=  25 cons: SET
    1339:d=8  hl=2 l=  23 cons: SEQUENCE
    1341:d=9  hl=2 l=  10 prim: OBJECT            :domainCompon
   ent
    1353:d=9  hl=2 l=   9 prim: IA5STRING         :sandelman
    1364:d=7  hl=2 l=  28 cons: SET
    1366:d=8  hl=2 l=  26 cons: SEQUENCE
    1368:d=9  hl=2 l=   3 prim: OBJECT            :commonName
    1373:d=9  hl=2 l=  19 prim: UTF8STRING        :Unstrung Hig
   hway CA
    1394:d=6  hl=2 l=   1 prim: INTEGER           :01
    1397:d=5  hl=2 l=  13 cons: SEQUENCE
    1399:d=6  hl=2 l=   9 prim: OBJECT            :sha256
    1410:d=6  hl=2 l=   0 prim: NULL
    1412:d=5  hl=3 l= 228 cons: cont [ 0 ]
    1415:d=6  hl=2 l=  24 cons: SEQUENCE
    1417:d=7  hl=2 l=   9 prim: OBJECT            :contentType
    1428:d=7  hl=2 l=  11 cons: SET
    1430:d=8  hl=2 l=   9 prim: OBJECT            :pkcs7-data
    1441:d=6  hl=2 l=  28 cons: SEQUENCE
    1443:d=7  hl=2 l=   9 prim: OBJECT            :signingTime
    1454:d=7  hl=2 l=  15 cons: SET
    1456:d=8  hl=2 l=  13 prim: UTCTIME           :171012175431
   Z
    1471:d=6  hl=2 l=  47 cons: SEQUENCE
    1473:d=7  hl=2 l=   9 prim: OBJECT            :messageDiges
   t
    1484:d=7  hl=2 l=  34 cons: SET
    1486:d=8  hl=2 l=  32 prim: OCTET STRING      [HEX DUMP]:41
   79C6EB6F1C216F0CA187C1D658C30E52E5250971103DAD9E372F90B11F8B
   1D
    1520:d=6  hl=2 l= 121 cons: SEQUENCE
    1522:d=7  hl=2 l=   9 prim: OBJECT            :S/MIME Capab
   ilities
    1533:d=7  hl=2 l= 108 cons: SET
    1535:d=8  hl=2 l= 106 cons: SEQUENCE
    1537:d=9  hl=2 l=  11 cons: SEQUENCE
    1539:d=10 hl=2 l=   9 prim: OBJECT            :aes-256-cbc
    1550:d=9  hl=2 l=  11 cons: SEQUENCE
    1552:d=10 hl=2 l=   9 prim: OBJECT            :aes-192-cbc
    1563:d=9  hl=2 l=  11 cons: SEQUENCE
    1565:d=10 hl=2 l=   9 prim: OBJECT            :aes-128-cbc
    1576:d=9  hl=2 l=  10 cons: SEQUENCE
    1578:d=10 hl=2 l=   8 prim: OBJECT            :des-ede3-cbc
    1588:d=9  hl=2 l=  14 cons: SEQUENCE
    1590:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    1600:d=10 hl=2 l=   2 prim: INTEGER           :80
    1604:d=9  hl=2 l=  13 cons: SEQUENCE
    1606:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    1616:d=10 hl=2 l=   1 prim: INTEGER           :40
    1619:d=9  hl=2 l=   7 cons: SEQUENCE
    1621:d=10 hl=2 l=   5 prim: OBJECT            :des-cbc
    1628:d=9  hl=2 l=  13 cons: SEQUENCE
    1630:d=10 hl=2 l=   8 prim: OBJECT            :rc2-cbc
    1640:d=10 hl=2 l=   1 prim: INTEGER           :28
    1643:d=5  hl=2 l=  10 cons: SEQUENCE
    1645:d=6  hl=2 l=   8 prim: OBJECT            :ecdsa-with-S
   HA256
    1655:d=5  hl=2 l= 103 prim: OCTET STRING      [HEX DUMP]:30
   6502310087389DFC090D8EDB6948FD6B7E5369A5D1EC8B7DB8676F935C9C
   6E79EC2727CCFFD8D5DBF937F70EC4E1BFB76ED343B3023063C8E9E69244
   8A1EC3D1D8996E03973AC28BEE3C49CD28FDF675A1867852861073244C89
   DBAEA8A90BCF35FF92BD43E9

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/

   Michael H. Behringer

   Email: Michael.H.Behringer@gmail.com

   Steinthor Bjarnason
   Arbor Networks

   Email: sbjarnason@arbor.net

   Kent Watsen
   Juniper Networks

   Email: kwatsen@juniper.net