ANIMA WG                                                     M. Pritikin
Internet-Draft                                                     Cisco
Intended status: Informational Standards Track                           M. Richardson
Expires: September 14, November 24, 2017                                           SSW
                                                            M. Behringer
                                                            S. Bjarnason
                                                                   Cisco
                                                               K. Watsen
                                                        Juniper Networks
                                                          March 13,
                                                            May 23, 2017

        Bootstrapping Remote Secure Key Infrastructures (BRSKI)
               draft-ietf-anima-bootstrapping-keyinfra-05
               draft-ietf-anima-bootstrapping-keyinfra-06

Abstract

   This document specifies automated bootstrapping of a remote secure
   key infrastructure (BRSKI) using vendor installed X.509 certificate,
   in combination with a vendor's authorizing service, both online the
   Internet, 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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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4   3
     1.1.  Secure Imprinting without Vouchers  Other Bootstrapping Approaches  . . . . . . . . . . .   5 . .   4
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   6   5
     1.3.  Scope of solution . . . . . . . . . . . . . . . . . . . .   8   7
   2.  Architectural Overview  . . . . . . . . . . . . . . . . . . .   9
     2.1.  Secure Imprinting without using Vouchers  . . . . . . . . . . .  11 .  10
     2.2.  Secure Imprinting using Vouchers  Initial Device Identifier . . . . . . . . . . . .  12
     2.3.  Initial Device Identifier . . . .  10
     2.3.  Protocol Flow . . . . . . . . . . . .  12
   3.  Functional Overview . . . . . . . . . .  12
     2.4.  Lack of realtime clock  . . . . . . . . . . .  13
     3.1.  Behavior of a Pledge . . . . . .  13
     2.5.  Cloud Registrar . . . . . . . . . . . .  15
       3.1.1.  Discovery . . . . . . . . .  14
   3.  Protocol Details  . . . . . . . . . . . . .  17
       3.1.2.  Identity . . . . . . . . .  14
     3.1.  Discovery . . . . . . . . . . . . .  18
       3.1.3.  Request Join . . . . . . . . . . .  16
       3.1.1.  Proxy Discovery Protocol Details  . . . . . . . . .  18
       3.1.4.  Imprint .  17
       3.1.2.  Registrar Discovery Protocol Details  . . . . . . . .  17
     3.2.  Request Voucher from the Registrar  . . . . . . . . . . .  18
     3.3.  Request Voucher from MASA . . .  19
       3.1.5.  Lack of realtime clock . . . . . . . . . . . . .  20
     3.4.  Voucher Response  . .  19
       3.1.6.  Enrollment . . . . . . . . . . . . . . . . . .  21
       3.4.1.  Completing authentication of Provisional TLS
               connection  . . .  20
       3.1.7.  Being Managed . . . . . . . . . . . . . . . . . .  22
     3.5.  Voucher Status Telemetry  . .  20
     3.2.  Behavior of a Join Proxy . . . . . . . . . . . . . .  23
     3.6.  MASA authorization log Request  . .  21
       3.2.1.  CoAP connection to Registrar . . . . . . . . . . .  24
     3.7.  MASA authorization log Response .  22
       3.2.2.  HTTPS proxy connection to Registrar . . . . . . . . .  22
     3.3.  Behavior of the Registrar . . .  24
     3.8.  EST Integration for PKI bootstrapping . . . . . . . . . .  26
       3.8.1.  EST Distribution of CA Certificates . . .  22
       3.3.1.  Pledge Authentication . . . . . .  26
       3.8.2.  EST CSR Attributes  . . . . . . . . . .  23
       3.3.2.  Pledge Authorization . . . . . . .  27
       3.8.3.  EST Client Certificate Request  . . . . . . . . .  24
       3.3.3.  Claiming the New Entity . .  27
       3.8.4.  Enrollment Status Telemetry . . . . . . . . . . . . .  24
       3.3.4.  Log Verification  27
       3.8.5.  EST over CoAP . . . . . . . . . . . . . . . . . .  25
     3.4.  Behavior of the MASA Service . .  29
   4.  Reduced security operational modes  . . . . . . . . . . . .  26
     3.5.  Leveraging the new key infrastructure / next steps .  29
     4.1.  Trust Model . .  26
       3.5.1.  Network boundaries . . . . . . . . . . . . . . . . .  26
     3.6.  Interactions with Network Access Control . . . .  29
     4.2.  New Entity security reductions  . . . .  27
   4.  Domain Operator Activities . . . . . . . . .  30
     4.3.  Registrar security reductions . . . . . . . .  27
     4.1.  Instantiating the Domain Certification Authority . . . .  27
     4.2.  Instantiating the Registrar . .  30
     4.4.  MASA security reductions  . . . . . . . . . . . . .  27
     4.3.  Accepting New Entities . . .  31
   5.  IANA Considerations . . . . . . . . . . . . . .  28
     4.4.  Automatic Enrollment of Devices . . . . . . .  32
     5.1.  PKIX Registry . . . . . .  29
     4.5.  Secure Network Operations . . . . . . . . . . . . . . . .  29
   5.  Proxy Discovery Protocol Details  32
   6.  Security Considerations . . . . . . . . . . . . . .  29
   6.  Registrar Discovery Protocol Details . . . . .  32
   7.  Acknowledgements  . . . . . . .  29
   7.  Protocol Details . . . . . . . . . . . . . . .  34
   8.  References  . . . . . . . . . .  30
     7.1.  Request Voucher from the Registrar . . . . . . . . . . .  34
     7.2.  Request Voucher from MASA . . . .  34
     8.1.  Normative References  . . . . . . . . . . . .  35
     7.3.  Voucher Response . . . . . .  34
     8.2.  Informative References  . . . . . . . . . . . . . .  36
       7.3.1.  Completing authentication of Provisional TLS
               connection . . .  35
   Appendix A.  IPv4 operations  . . . . . . . . . . . . . . . . . .  37
     7.4.  Voucher Status Telemetry
     A.1.  IPv4 Link Local addresses . . . . . . . . . . . . . . . .  38
     7.5.  MASA authorization log Request  37
     A.2.  Use of DHCPv4 . . . . . . . . . . . . .  39
     7.6.  MASA authorization log Response . . . . . . . . .  37
   Appendix B.  mDNS / DNSSD proxy discovery options . . . .  39
     7.7.  EST Integration for PKI bootstrapping . . . .  37
   Appendix C.  IPIP Join Proxy mechanism  . . . . . .  40
       7.7.1.  EST Distribution of CA Certificates . . . . . . .  38
     C.1.  Multiple Join networks on the Join Proxy side . .  41
       7.7.2.  EST CSR Attributes . . . .  39
     C.2.  Automatic configuration of tunnels on Registrar . . . . .  39
     C.3.  Proxy Neighbor Discovery by Join Proxy  . . . . . . . .  41
       7.7.3.  EST Client Certificate Request .  39
     C.4.  Use of connected sockets; or IP_PKTINFO for CoAP on
           Registrar . . . . . . . . . .  42
       7.7.4.  Enrollment Status Telemetry . . . . . . . . . . . . .  42
       7.7.5.  EST over CoAP .  40
     C.5.  Use of socket extension rather than virtual interface . .  40
   Appendix D.  To be deprecated: Consolidation remnants . . . . . .  40
     D.1.  Functional Overview . . . . . . . . . . .  43
   8.  Reduced security operational modes . . . . . . . .  41
       D.1.1.  Behavior of a Pledge  . . . . .  43
     8.1.  Trust Model . . . . . . . . . . .  44
       D.1.2.  Behavior of a Join Proxy  . . . . . . . . . . . .  43
     8.2.  New Entity security reductions . .  50
       D.1.3.  Behavior of the Registrar . . . . . . . . . . .  44
     8.3.  Registrar security reductions . . . . . . . . . . . . . .  44
     8.4.  MASA security reductions  . . . . . . . . . . . . . . . .  45
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  46
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  48
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  48
     11.1.  Normative References . . . . .  51
       D.1.4.  Behavior of the MASA Service  . . . . . . . . . . . .  55
       D.1.5.  Leveraging the new key infrastructure / next steps  .  48
     11.2.  Informative References  56
       D.1.6.  Interactions with Network Access Control  . . . . . .  56
     D.2.  Domain Operator Activities  . . . . . . . . . . .  49
   Appendix A.  IPv4 operations . . . .  56
       D.2.1.  Instantiating the Domain Certification Authority  . .  57
       D.2.2.  Instantiating the Registrar . . . . . . . . . . . .  51
     A.1.  IPv4 Link Local addresses .  57
       D.2.3.  Accepting New Entities  . . . . . . . . . . . . . . .  51
     A.2.  Use  57
       D.2.4.  Automatic Enrollment of DHCPv4 . . . . . . . . . . . . . . . Devices . . . . . . .  51
   Appendix B.  mDNS / DNSSD proxy discovery options . . . .  58
       D.2.5.  Secure Network Operations . . . .  51
   Appendix C.  IPIP Join Proxy mechanism . . . . . . . . . .  58
   Authors' Addresses  . . .  52
     C.1.  Multiple Join networks on the Join Proxy side . . . . . .  53
     C.2.  Automatic configuration of tunnels on Registrar . . . . .  53
     C.3.  Proxy Neighbor Discovery by Join Proxy . . . . . . . . .  53
     C.4.  Use  59

1.  Introduction

   BRSKI provides a foundation to securely answer the following
   questions between an element of connected sockets; or IP_PKTINFO for CoAP on
           Registrar . . . . . . . . . . . . . . . . . . . . . . . .  54
     C.5.  Use of socket extension rather than virtual interface . .  54
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  54

1.  Introduction

   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 is pre-provisioned on each new device in a costly and non-
   scalable manner.  These existing mechanisms are known as non-secured
   'Trust on First Use' (TOFU) [RFC7435], 'resurrecting duckling'
   [Stajano99theresurrecting] or 'pre-staging'.

   This document describes a zero-touch approach to bootstrapping that
   secures the initial distribution of key material between an
   unconfigured and untouched device called a "Pledge" and the
   "Registrar" device that is a member of an established network domain.
   The bootstrapping process provides a foundation to securely answer
   the following questions:

   o the network domain called the
   "Registrar" and an unconfigured and untouched device called a
   "Pledge":

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

   o  Registrar authorization the Pledge: "Is it mine?  Do I want it?
      What are the chances it has been compromised?"

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

   o  Pledge authorization 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, and local access
   control lists.  The Pledge actions derive from a cryptographically
   protected "voucher" message delivered through the Registrar.
   Multiple forms of "vouchers" are described to support a variety of
   use cases.

   The syntactic details of vouchers are described in detail in
   [I-D.ietf-anima-voucher].  This document details automated protocol
   mechanisms to obtain vouchers.

   The result of bootstrapping is that a security association between

   BRSKI results in the Pledge and storing an X.509 root certificate
   sufficient for verifying the Registrar identity.  In the process a
   TLS connection is established.  A method of leveraging
   this association established which can be directly used for
   Enrollment over Secure Transport (EST).  The Pledge can use these
   credentials to optimize PKI enrollment is described.

   The described system secure additional protocol exchanges.

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

1.1.  Secure Imprinting  Other Bootstrapping Approaches

   To literally "pull yourself up by the bootstraps" is an impossible
   action.  Similarly the secure establishment of a key infrastructure
   without Vouchers

   There are pre-existing methods available for establishing initial
   trust.  For example 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 is pre-provisioned on each new device in a costly and non-
   scalable manner.  Existing mechanisms are known as non-secured 'Trust
   on First Use' (TOFU) [RFC7435], 'resurrecting duckling'
   [Stajano99theresurrecting] or 'pre-staging'.

   Another approach is to try and minimize user actions during
   bootstrapping.  The enrollment protocol EST [RFC7030] details a set
   of non-autonomic bootstrapping methods such as: in this vein:

   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 vendor 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 vendor service,

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

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

   BRSKI addresses these issues by introducting an authorization layer
   via "vouchers".  The additional complexity provides for significant
   flexibility. defining "voucher" and automation
   extensions to the EST protocol.

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 domain trust anchor that is
      stored by the Domain CA.  This is consistent with the
      Certification Authority subject key identifier (Section 4.2.1.2
      [RFC5280]) of the Domain CA's self signed root certificate.  (A
      string value bound to the Domain CA's self signed root certificate
      subject and issuer fields is often colloquially used as a
      humanized identity value but during protocol discussions the more
      exact term as defined here is used).

   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 by a
      third-party (e.g., vendor, manufacturer or integrator).

   Voucher  A signed statement from the MASA service 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 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.

   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.

1.3.  Scope of solution

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

   The solution described in this document is aimed in general at non-
   constrained (i.e. class 2+) 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).

   There are a number of optional mechanisms in BRSKI.  These mechanisms
   are not mandatory to implement for the core applicability to ANIMA.
   These mechanisms have been moved out of the main flow of the document
   to appendices to emphasis that they are not considered normative,
   mandatory to implement, while making it easier for another document
   to normatively reference them.

   In many target applications, the systems involved are large router
   platforms with multi-gigabit inter-connections, mounted in controlled
   access data centers.  But this solution is not exclusive to the
   large, 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 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 it's
   presence through broadcasting.

   This protocol is not intended for low latency handoffs.  In networks
   requiring such things, the pledge SHOULD already have been enrolled.

   Specifically, there are protocol aspects described here which 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 constained devices.  It is simply the
   actual on-the-wire imprint protocol which could be inappropriate.

   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.

   Some aspects are in scope for constrained devices on challenged
   networks: the certificate contents, and the process by which the four
   questions above are resolved is in scope.  It is simply the actual
   on-the-wire imprint
   Integrating this protocol which with network access control, perhaps as an
   Extensible Authentication Protocol (EAP) method (see [RFC3748]), is likely inappropriate.
   out-of-scope.

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   |         |
      |                                      .+--------------+---------+
      |                                      ..............  ^
      V                                                      |
   +-------+     ............................................|...
   |       |     .                                           |  .
   |       |     .  +------------+       +-----------+       |  .
   |       |     .  |            |       |           |       |  .
   |Pledge |     .  |   Circuit  |       | Domain    <-------+  .
   |       |     .  |   Proxy    |       | Registrar |          .
   |       <-------->            <------->           |          .
   |       |     .  |            |       |           |          .
   |       |     .  +------------+       +-----+-----+          .
   |IDevID |     .                             |                .
   |       |     .           +-----------------+----------+     .
   |       |     .           | Domain Certification       | Key Infrastructure         |     .
   |       |     .           | Authority (e.g. PKI Certificate      |     .
   +-------+     .           | Management and etc       Authority)           |     .
                 .           +----------------------------+     .
                 .                                              .
                 ................................................
                               "Domain" components

   Figure 1

   We assume a multi-vendor network.  In such an environment there could
   be a Vendor Service for each vendor that supports devices following
   this document's specification, or an integrator could provide a
   generic service authorized by multiple vendors.  It is unlikely that
   an integrator could provide Ownership Tracking services for multiple
   vendors 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
   managed by. joining.  The a domain provides initial
   device connectivity
   minimally sufficient for bootstrapping through the with a Circuit
   Proxy.  The Domain registrar authenticates the Pledge, makes
   authorization decisions decisions, and handles
   connectivity to distributes vouchers obtained from the vendor services and authenticates
   Vendor Service.  Optionally the Pledge.
   Optional cryptographic credential and configuration management
   systems are expected.

   This document describes a secure zero-touch approach to bootstrapping Registrar also acts as a remote key infrastructure. PKI
   Registration Authority.

2.1.  Secure bootstrapping requires
   mitigating the threat of an attacker domain establishing Imprinting using Vouchers

   A voucher is a management
   role over cryptographically protected statement to the pledge device.  In Pledge
   device authorizing a "trust zero-touch imprint on first use" model, where
   this threat is ignored, the attacker has an opportunity to install a
   persistent malware component.  This document uses 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 address secure imprinting: the threat while maintaining
   Pledge device only imprints when a significant level voucher can be validated.  At the
   lowest security levels the MASA server can indiscriminately issue
   vouchers.  At the highest security levels issuance of flexibility.

2.1.  Secure Imprinting without Vouchers

   There vouchers can be
   integrated with complex sales channel integrations that are pre-existing methods available for establishing initial
   trust.  For example beyond
   the enrollment protocol EST [RFC7030] details a
   set scope of non-autonomic bootstrapping methods such as:

   o  using this document.  This provides the Implicit Trust Anchor database (not an autonomic
      solution because flexibility for a
   number of use cases via a single common protocol mechanism on the URL must
   Pledge and Registrar devices that are to be securely distributed),

   o  engaging a human user widely deployed in the
   field.  The MASA vendor services have the flexibility to authorize leverage
   either the CA certificate using out-
      of-band data (not currently defined claim mechanisms or to experiment with
   higher or lower security levels.

2.2.  Initial Device Identifier

   Pledge authentication is via an autonomic solution because X.509 certificate installed during
   the human user is
      involved),

   o  using manufacturing process.  This Initial Device Identifier provides a configured Explicit TA database (not an autonomic solution
      because
   basis for authenticating the distribution of an explicit TA database is not
      autonomic),

   o Pledge during subsequent protocol
   exchanges and using a Certificate-Less TLS mutual authentication method (not
      an autonomic solution because informing the distribution Registrar of symmetric key
      material is not autonomic).

   These "touch" methods do not meet the requirements for zero-touch. MASA URI.  There are "call home" technologies where the Pledge first establishes
   a connection to a well known vendor service using is no
   requirement for a common client-
   server authentication model.  After mutual authentication appropriate
   credentials to authenticate the target domain root PKI hierarchy.  Each device vendor can
   generate their own root certificate.

   The following previously defined fields are transfered to in the
   Pledge.  This creates serveral problems and limitations: X.509 IDevID
   certificate:

   o  The subject field's DN encoding MUST include the pledge requires realtime connectivity to "serialNumber"
      attribute with the vendor service, device's unique serial number.

   o  the domain identity is exposed to the vendor service (this is  The subject-alt field's encoding SHOULD include a
      privacy concern),

   o non-critical
      version of the vendor is responsible for making RFC4108 defined HardwareModuleName.

   The following newly defined field SHOULD be in the authorization decisions
      (this is X.509 IDevID
   certificate: An X.509 non-critical certificate extension that
   contains a liability concern),

   BRSKI addresses these issues by introducting an authorization layer
   via "vouchers".  The additional complexity provides for significant
   flexibility.

2.2.  Secure Imprinting using Vouchers

   A voucher is a cryptographically protected statement single Uniform Resource Identifier (URI) that points to the Pledge
   device authorizing a zero-touch imprint on the Registrar domain. an
   on-line Manufacturer Authorized Signing Authority.  The format and cryptographic mechanism of vouchers URI is
   represented as 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.  At the highest security levels issuance Section 7.4 of vouchers can [RFC5280].

   Any Internationalized Resource Identifiers (IRIs) MUST be
   integrated with complex sales channel integrations that are beyond
   the scope of this document.  This provides the flexability for a
   number mapped to
   URIs as specified in Section 3.1 of use cases via a single common protocol mechanism on the
   Pledge and Registrar devices that [RFC3987] before they are to be widely deployed placed
   in the
   field.  The MASA vendor services have the flexibility to leverage
   either the currently defined claim mechanisms or to experiment with
   higher or lower security levels.

2.3.  Initial Device Identifier

   Pledge authentication is via an X.509 certificate installed during
   the manufacturing process.  This Initial Device Identifier extension.  The URI provides a
   basis for authenticating the Pledge during subsequent protocol
   exchanges and informing the Registrar of the MASA URI.  There is no
   requirement for a common root PKI hierarchy.  Each device vendor can
   generate their own root certificate. authority
   information.  The following previously defined fields are BRSKI .well-known tree is described in the X.509 IDevID
   certificate:

   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 the a non-critical
      version of the RFC4108 defined HardwareModuleName.

   The following newly defined field SHOULD be in the X.509 IDevID
   certificate: An X.509 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 semantics of the URI are defined in Section 7 of this document. Section 3

   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.

3.  Functional Overview

   Entities behave in an autonomic fashion.  They discover each other
   and autonomically bootstrap into a key infrastructure delineating the
   autonomic domain.  See [RFC7575] for more information.

   This section details the state machine and operational flow for each
   of the main three entities.  The pledge, the domain (primarily a
   Registrar) and the MASA service.

2.3.  Protocol Flow

   A representative flow is shown in Figure 2:

   +--------+         +---------+    +------------+     +------------+
   | Pledge |         | Circuit |    | Domain     |     | Vendor     |
   |        |         | Proxy   |    | Registrar  |     | Service    |
   |        |         |         |    |            |     | (Internet  |
   +--------+         +---------+    +------------+     +------------+
     |                     |                   |                    |
     |<-RFC3927 IPv4 adr   | Appendix A        |                    |
   or|<-RFC4862 IPv6 adr   |                   |                    |
     |                     |                   |                    |
     |-------------------->|                   |                    |
     | optional: mDNS query| Appendix B        |                    |
     | RFC6763/RFC6762     |                   |                    |
     |                     |                   |                    |
     |<--------------------|                   |                    |
     | 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---Request Voucher (include nonce)------>|                    |
     P                     |                   |                    |
     P                     |       /--->       |                    |
     P                     |       |      [accept device?]          |
     P                     |       |      [contact Vendor]          |
     P                     |       |           |--Pledge ID-------->|
     P                     |       |           |--Domain ID-------->|
     P                     |       |           |--optional:nonce--->|
     P                     |       |           |     [extract DomainID]
     P                     |       |           |                    |
     P                     |    optional:      |     [update audit log]
     P                     |       |can        |                    |
     P                     |       |occur      |                    |
     P                     |       |in         |                    |
     P                     |       |advance    |                    |
     P                     |       |           |                    |
     P                     |       |           |<-device audit log--|
     P                     |       |           |<- voucher ---------|
     P                     |       \---->      |                    |
     P                     |                   |                    |
     P                     |       [verify audit log and voucher]   |
     P                     |                   |                    |
     P<------voucher---------------------------|                    |
   [verify voucher ]       |                   |                    |
   [verify provisional cert ]| cert|                   |                    |
     |                     |                   |                    |
      |---------------------------------------->|
     |<--------------------------------------->|                    |
     | Continue with RFC7030 enrollment        |                    |
     | using now bidirectionally authenticated |                    |
     | TLS session.        |                   |                    |
     |                     |                   |                    |
     |                     |                   |                    |
     |                     |                   |                    |

   Figure 2

3.1.  Behavior

2.4.  Lack of a Pledge

   A pledge that has realtime clock

   Many devices when bootstrapping do not yet been bootstrapped attempts to find a local
   domain and join it.  A pledge MUST NOT automatically initiate have knowledge of the current
   time.  Mechanisms like Network Time Protocols can not be secured
   until bootstrapping is complete.  Therefore bootstrapping if it has already been configured or is defined
   in the process
   of being configured.

   States of a pledge method that does not require knowledge of the current time.

   Unfortunately there are as follows:

                +--------------+
                |   Start      |
                |              |
                +------+-------+
                       |
                +------v-------+
                |  Discover    |
   +------------>              |
   |            +------+-------+
   |                   |
   |            +------v-------+
   |            |  Identity    |
   ^------------+              |
   | rejected   +------+-------+
   |                   |
   |            +------v-------+
   |            | Request      |
   |            | Join         |
   |            +------+-------+
   |                   |
   |            +------v-------+
   |            |  Imprint     |   Optional
   ^------------+              <--+Manual input (Appendix C)
   | Bad Vendor +------+-------+
   | response          |
   |            +------v-------+
   |            |  Enroll      |
   ^------------+              |
   | Enroll     +------+-------+
   | Failure           |
   |            +------v-------+
   |            |  Being       |
   ^------------+  Managed     |
    Factory     +--------------+
    reset

   Figure 3

   State descriptions for the pledge moments during bootstrapping when
   certificates are verified, such as follows:

   1.  Discover a communication channel to a Registrar.

   2.  Identify itself. during the TLS handshake, where
   validity periods are confirmed.  This paradoxical "catch-22" is done
   resolved by presenting an X.509 IDevID
       credential to the discovered Registrar (via the Proxy) in Pledge maintaining a TLS
       handshake.  (The Registrar credentials are only provisionally
       accepted at this time).

   3.  Requests 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 concept of the Registrar.  This requires verification current "window"
   of presumed time validity that is continually refined throughout the
       vendor service provided voucher.  A voucher contains sufficient
       information for
   bootstrapping process as follows:

   o  Initially the Pledge to complete authentication of a
       Registrar.  (It enables does not know the current time.

   o  During Pledge to finish authentication of authentiation by the Registrar TLS server certificate).

   5.  Enroll.  By accepting the domain specific information from a
       Registrar, and realtime clock can
      be used by obtaining a domain certificate from a Registrar
       using the Registrar.  This bullet expands on a standard enrollment protocol, e.g.  Enrollment over
       Secure Transport (EST) [RFC7030].

   6.  The closely
      related issue regarding Pledge is now a member of, and can lifetimes.  RFC5280 indicates that
      long lived Pledge certifiates "SHOULD be managed by, the domain
       and will only repeat assigned the discovery aspects
      GeneralizedTime value of bootstrapping 99991231235959Z" [RFC7030] so the
      Registrar MUST support such lifetimes and SHOULD support ignoring
      Pledge lifetimes if it
       is returned to factory default settings.

   The following sections describe each of these steps in more detail.

3.1.1.  Discovery

   The result of discovery is a logical communication with a Registrar,
   through a Proxy.  The Proxy is transparent to they did not follow the RFC5280
      recommendations.

   o  The Pledge but is
   always assumed to exist.

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

   o  If the following actions:

   a.  MUST: Obtains voucher contains a local address using IPv6 methods as described in
       [RFC4862] IPv6 Stateless Address AutoConfiguration.  [RFC7217] is
       encouraged.  IPv4 methods are described in Appendix A

   b.  MUST: Listen for GRASP M_FLOOD ([I-D.ietf-anima-grasp])
       announcements of nonce then the objective: "ACP+Proxy".  See section
       Section 5 for Pledge MUST confirm the details of
      nonce matches the original voucher request.  This ensures the objective.  The Pledge may
       listen concurrently for other sources of information, see
       Appendix B.

   Once a proxy
      voucher is discovered fresh.  See / (Section 3.2).

   o  Once the Pledge communicates with a Registrar
   through voucher is accepted the proxy using validity period of the bootstrapping protocol defined
      domainCAcert in the voucher (see Section 7.

   Each discovery method attempted SHOULD exponentially back-off
   attempts (to 3.4) now serves as a maximum of one hour)
      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 avoid overloading be valid by the network
   infrastructure with discovery. Pledge.
      The back-off timer for each method
   MUST be independent of other methods.  Methods SHOULD be run in
   parallel Pledge is now willing to avoid head of queue problems.  Once use this credential for client
      authentication.

2.5.  Cloud Registrar

   The Pledge MAY contact a connection to well known URI of a cloud Registrar is established (e.g. establishment of if a TLS session key)
   there are expectations of more timely responses, see Section 7.1.

   Once all
   local Registrar can not be discovered services are attempted or if the device SHOULD return
   to listening for GRASP M_FLOOD.  It should periodically retry Pledge's target use
   cases do not include a local Registrar.

   If the
   vendor specific mechanisms.  The Pledge MAY prioritize selection
   order as appropriate 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 anticipated environment.

3.1.2.  Identity human user configuration of an EST server URI in [RFC7030]
   which also depends on RFC6125.

3.  Protocol Details

   The Pledge identifies itself during the communication protocol
   handshake.  If the client identity MUST initiate BRSKI after boot if it is rejected (that is, the TLS
   handshake does not complete) the Pledge repeats the Identity process
   using the next proxy or discovery method available. unconfigured.  The bootstrapping protocol server
   Pledge MUST NOT automatically initiate BRSKI if it has been
   configured or is not initially authenticated.
   Thus in the connection is provisional and all data received is untrusted
   until sufficiently validated even though it process of being configured.

   BRSKI is over a described as extensions to EST [RFC7030] to reduce the
   number of TLS connection.
   This is aligned with 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 provisional mode of EST URIs as described in
   EST [RFC7030]
   during s4.1.1 "Bootstrap Distribution section 3.2.2.  A MASA URI is therefore "https://
   authority "./well-known/est".

   Establishment of CA Certificates".  See
   Section 7.3 for more information about when the TLS connection
   authentication for bootstrapping is completed.

   All security associations established are between as specified
   in EST [RFC7030] section 4.1.1 "Bootstrap Distribution of CA
   Certificates" [RFC7030] with the new device and following extensions for automation:

   Automation extensions for the Bootstrapping server regardless of proxy operations.

3.1.2.1.  Concurrent attempts Pledge (equivalent to join EST client) are:

   o  The Pledge MAY attempt multiple mechanisms concurrently, but if it
   does so, it MUST wait in provisionally accepts the provisional state until all mechanisms
   have either succeeded or failed, and then MUST proceed with Registrar certificate during
      the
   highest priority mechanism which has succeed.  To proceed beyond this
   point, specifically, to provide a nonce, could result TLS handshake as detailed in EST.

   o  If the MASA
   gratuitously auditing a connection.

3.1.3.  Request Join

   The Pledge POSTs Registrar responds with a request to join the domain redirection to the Bootstrapping
   server.  This request contains a Pledge generated nonce and informs
   the Bootstrapping server which imprint methods other web origins
      the Pledge will
   accept.

   The nonce ensures the Pledge can verify that responses are specific
   to this bootstrapping attempt.  This minimizes the use of global time
   and provides MUST follow only a substantial benefit for devices single redirection.  (EST supports
      redirection but does not allow redirections to other web origins
      without a valid clock.

3.1.3.1.  Redirects during the Join Process

   EST [RFC7030] describes situations where the bootstrapping server user input).

   o  The Registar MAY
   redirect the client to respond with an alternate server via a 3xx status code.
   Such redirects MAY be HTTP 202 ("the request has been
      accepted if for processing, but the pledge processing has used the methods not been
      completed") as described in Appendix B, in combination with an implicit trust
   anchor.  Redirects during EST [RFC7030] section 4.2.3 wherein
      the provisional period are otherwise
   unstrusted, and MUST cause a failure.

3.1.4.  Imprint

   The Pledge validates client "MUST wait at least the voucher and accepts specified 'retry-after' time
      before repeating the Registrar ID. same request".  The
   provisional TLS connection Pledge is validated using the RECOMMENDED to
      provide local feed (blinked LED etc) during this wait cycle if
      mechanisms for this are available.  To prevent an attacker
      Registrar ID from
   the voucher.

3.1.5.  Lack of realtime clock

   Many devices when bootstrapping do not have knowledge of the current
   time.  Mechanisms like Network Time Protocols can not 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 significantly delaying 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
      MUST limit the current "window"
   of presumed 'retry-after' time validity that is continually refined throughout the
   bootstrapping process as follows:

   o  Initially to 60 seconds.  To avoid waiting
      on a single erroneous Registrar the Pledge does not know MUST drop the
      connection after 5 seconds and proceed to other discovered
      Registrars.  Ideally the current time.

   o  During Pledge authentiation by could keep track of the Registrar
      appropriate retry-after value for any number of outstanding
      Registrars but this would involve a realtime clock can
      be used by the Registrar.  This bullet expands large state table on a closely
      related issue regarding Pledge lifetimes.  RFC5280 indicates that
      long lived the
      Pledge.  Instead the Pledge certifiates "SHOULD be assigned MAY ignore the
      GeneralizedTime exact retry-after value
      in favor of 99991231235959Z" [RFC7030] so the a single hard coded value that takes effect between
      discovery (Appendix D.1.1.1) attempts.  A Registrar MUST support such lifetimes and SHOULD support ignoring
      Pledge lifetimes if they did not follow that is unable
      to complete the RFC5280
      recommendations. transaction the first time due to timing reasons
      will have future chances.

   o  The Pledge authenticates the requests and validates a voucher presented to it.  During this
      authentication using the new REST
      calls described below.

   o  If necessary the Pledge ignores certificate lifetimes (by
      necessity because it does not have a clock).  The voucher itself
      SHOULD contain calls the nonce included in EST defined /cacerts method to
      obtain the original request which
      proves current CA certificate.  These are validated using the voucher is fresh.
      Voucher.

   o  Once  The Pledge completes authentication of the voucher is accepted server certificate as
      detailed in Section 3.4.1.  This moves the validity period TLS connection out of
      the
      domainCAcert in provisional state.  Optionally the voucher (see Section 7.3) TLS connection can 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.
      used for EST enrollment.

   The Pledge is now willing to use this credential for client
      authentication.

3.1.6.  Enrollment

   As establishes the final step of bootstrapping a Registrar helps to issue a
   domain specific credential to TLS connection with the Pledge.  For simplicity in this
   document, a Registrar primarily facilitates issuing a credential by
   acting as an RFC5280 Registration Authority for through
   the Domain
   Certification Authority.

   Enrollment proceeds as described in [RFC7030].  Authentication of circuit proxy (see Appendix D.1.2) but the
   EST server TLS connection is done using the Voucher rather than with
   the methods defined Registar; so in EST.

   Once the Voucher above section the "Pledge" is received, as specified in this document, the TLS client has sufficient information to leverage
   and the existing
   communication channel with "Registrar" is the TLS server.  All security associations
   established are between the new device and the Registrar regardless
   of proxy operations.

   The extensions for a Registrar (equivalent to continue an EST RFC7030
   enrollment.  Enrollment picks up at RFC7030 section 4.1.1.
   bootstrapping where server) are:

   o  Client authentication is automated using Initial Device Identity.
      The subject field's DN encoding MUST include the Voucher provides "serialNumber"
      attribute with the "out-of-band" CA
   certificate fingerprint (in this case device's unique serial number.  In the full CA certificate) such language
      of RFC6125 this provides for a SERIALNUM-ID category of identifier
      that the client can now complete the TLS server authentication.  At
   this point the client continues with EST enrollment operations
   including "CA Certificates Request", "CSR Attributes" and "Client
   Certificate Request" or "Server-Side Key Generation".

   For the purposes of creating the ANIMA Autonomic Control Plane, the
   contents of the new be included in a certificate MUST and therefore that can also
      be carefully specified.
   [I-D.ietf-anima-autonomic-control-plane] section 5.1.1 contains
   details. used for matching purposes.  The SERIALNUM-ID whitelist is
      collated according to vendor trust anchor since serial numbers are
      not globally unique.

   o  The Registrar MUST provide requests and validates the Voucher from the correct ACP information vendor
      authorized MASA service.

   o  The Registrar forwards the Voucher to populate the subjectAltName / rfc822Name field Pledge when requested.

   o  The Registar performs log verifications in the "CSR
   Attributes" step.

3.1.7.  Being Managed

   Functionality addition to provide generic "configuration" information is
   supported. local
      authorization checks before accepting optional Pledge device
      enrollment requests.

3.1.  Discovery

   The parsing of this data and any subsequent use result of the
   data, for example communications discovery is a logical communication with a Network Management System is
   out of scope but Registrar,
   through a Proxy.  The Proxy is expected transparent to occur after bootstrapping enrollment
   is complete.  This ensures that all communications with management
   systems which can divulge local security information (e.g. network
   topology or raw key material) is secured using the local credentials
   issued during enrollment.

   The Pledge uses bootstrapping to join only one domain.  Management by
   multiple domains but is out-of-scope of bootstrapping.  After
   always assumed to exist.

   To discover the device
   has successfully joined a domain and is being managed it is plausible
   that Registrar the domain can insert credentials for other domains depending on Pledge performs the device capabilities.

   See Section 3.5.

3.2.  Behavior of following actions:

   a.  MUST: Obtains a Join Proxy

   The role of the Proxy local address using IPv6 methods as described in
       [RFC4862] IPv6 Stateless Address AutoConfiguration.  [RFC7217] is to facilitate communications.  The Proxy
   forwards packets between the Pledge
       encouraged.  Pledges will generally prefer use of IPv6 Link-Local
       addresses, and a Registrar that has been
   configured on the Proxy.

   The Proxy does not terminate the TLS handshake.

   A discovery of Proxy is always assumed even if it is directly integrated into a
   Registrar.  (In will be by Link-Local
       mechanisms.  [[EDNOTE: In some environments, a completely autonomic network, the Registrar MUST
   provide proxy functionality so that routable public
       address may be obtained, should it be?  Should it can be discovered, and the
   network can grow concentrically around the Registrar)

   As a result used?]] IPv4
       methods are described in Appendix A

   b.  MUST: Listen for GRASP M_FLOOD ([I-D.ietf-anima-grasp])
       announcements of the Proxy Discovery process in objective: "ACP+Proxy".  See section
       Section 3.1.1,
   the port number exposed by the proxy does not need to be well known,
   or require an IANA allocation.

   If the Proxy joins an Autonomic Control Plane
   ([I-D.ietf-anima-autonomic-control-plane]) it SHOULD use Autonomic
   Control Plane secured GRASP ([I-D.ietf-anima-grasp]) to discovery 3.1.1 for the
   Registrar address and port.  As part details of the discovery process, the objective.  The Pledge
       may listen concurrently for other sources of information, see
       Appendix B.

   Once a proxy mechanism (Circuit Proxy vs IPIP encapsulation) is agreed to
   between discovered the Pledge communicates with a Registrar and Join Proxy.

   For the IPIP encapsulation methods, the port announced by the Proxy
   MUST be
   through the same as on proxy using the registrar bootstrapping protocol defined in order for the proxy
   Section 3.

   Each discovery method attempted SHOULD exponentially back-off
   attempts (to a maximum of one hour) to remain
   stateless.

   In order to permit avoid overloading the proxy functionality to network
   infrastructure with discovery.  The back-off timer for each method
   MUST be implemented on the
   maximum variety independent of devices the chosen mechanism other methods.

   Methods 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 run in the control plane CPU parallel to avoid head of such queue problems
   wherein an attacker running a device, with available capabilities for the fake proxy function similar
   to many class 2 IoT devices.

   The document [I-D.richardson-anima-state-for-joinrouter] provides or registrar can operate
   protocol actions intentionally slowly.

   Once a
   more extensive analysis of the alternative proxy methods.

3.2.1.  CoAP connection to Registrar

   The CoAP mechanism was depreciated.

3.2.2.  HTTPS proxy connection to a Registrar

   The proxy SHOULD also provide one of: an IPIP encapsulation is established (e.g. establishment
   of HTTP
   traffic on TCP port TBD to the registrar, or a TCP circuit proxy that
   connects TLS session key) there are expectations of more timely
   responses, see Section 3.2.

   Once all discovered services are attempted the Pledge device SHOULD return
   to a Registrar.

   When listening for GRASP M_FLOOD.  It should periodically retry the
   vendor specific mechanisms.  The Pledge MAY prioritize selection
   order as appropriate for the anticipated environment.

3.1.1.  Proxy provides a circuit Discovery Protocol Details

   The proxy to a Registrar the Registrar
   MUST accept HTTPS connections.

   When uses the Proxy provides a stateless IPIP encapsulation GRASP M_FLOOD mechanism to a
   Registrar, then announce itself.  This
   announcement is done with the Registrar will have to perform IPIP
   decapsulation, remembering same message as the originating outer IPIP source address ACP announcement
   detailed in order to qualify [I-D.ietf-anima-autonomic-control-plane].

    proxy-objective = ["Proxy", [ O_IPv6_LOCATOR, ipv6-address,
    transport-proto, port-number ] ]

    ipv6-address       - the inner link-local address.  This is a kind v6 LL of
   encapsulation and processing which is similar in many ways to how
   mobile IP works.

   Being able to connect a the proxy
    transport-proto    - 6, for TCP (HTTP) or UDP (CoAP) socket to a link-
   local address with an encapsulated IPIP header requires API
   extensions beyond [RFC3542] 17 for UDP use, and requires a form of
   connection latching (see section 4.1 of [RFC5386] and all of
   [RFC5660], except that a simple IPIP tunnel is used rather than an
   IPsec tunnel).

3.3.  Behavior of the Registrar

   A Registrar listens for Pledges and determines if they can join the
   domain.  A Registrar obtains a Voucher from
    port-number        - the MASA service and
   delivers them TCP or UDP port number to find the Pledge as well as facilitating enrollment with
   the domain PKI. proxy

   Figure 5

3.1.2.  Registrar Discovery Protocol Details

   A Registrar is typically configured manually.  When the Registrar
   joins an Autonomic Control Plane
   ([I-D.ietf-anima-autonomic-control-plane]) it MUST respond to GRASP
   ([I-D.ietf-anima-grasp]) M_DISCOVERY M_NEG_SYN message.  See Section 6

   Registrar behavior is

   The registrar responds to discovery messages from the proxy (or GRASP
   caches between them) as follows:

   Contacted by Pledge
           +
           |
   +-------v----------+
   | Entity           | fail?
   | Authentication   +---------+
   +-------+----------+         |
           |                    |
   +-------v----------+         |
   | Entity           | fail?   |
   | Authorization    +--------->
   +-------+----------+         |
           |                    |
   +-------v----------+         |
   | Claiming (XXX changed from M_DISCOVERY)

    objective         = ["AN_registrar", F_DISC, 255 ]
    discovery-message = [M_NEG_SYN, session-id, initiator, objective]

   Figure 6: Registrar Discovery

   The response from the     | fail?   |
   | Entity           +--------->
   +-------+----------+         |
           |                    |
   +-------v----------+         |
   | Log Verification | fail?   |
   |                  +--------->
   +-------+----------+         |
           |                    |
   +-------v----------+    +----v-------+
   | Forward          |    |            |
   | Voucher          |    | Reject     |
   | to registrar (or cache) will be a M_RESPONSE with
   the Pledge    |    | Device     |
   |                  |    |            |
   +------------------+    +------------+ following parameters:

    response-message = [M_RESPONSE, session-id, initiator, ttl,
    (+locator-option // divert-option), ?objective)]
    initiator = ACP address of Registrar
    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]

   Figure 4

3.3.1.  Pledge Authentication 7: Registrar Response

   The applicable authentication methods detailed in EST [RFC7030] are:

   o  the use set of an X.509 IDevID credential during the TLS client
      authentication,

   o  or the use locators is to be interpreted as follows.  A protocol of a secret 6
   indicates that TCP proxying on the indicated port is transmitted out desired.  A
   protocol of band between 17 indicates that UDP proxying on the
      Pledge and a Registrar (this use case indicated port is not autonomic).
   desired.  In order to validate each case, the X.509 IDevID credential a Registrar
   maintains a database of vendor trust anchors (e.g. vendor root
   certificates or keyIdentifiers for vendor root public keys).  For
   user interface purposes this database can traffic SHOULD be mapped proxied to colloquial
   vendor names.  Registrars can be shipped with the trust anchors same
   port at the ULA address provided.

   A protocol of a
   significant number 41 indicates that packets may be IPIP proxy'ed.  In the
   case of third-party vendors within that IPIP proxying is used, then the target market.

3.3.2.  Pledge Authorization

   In a fully automated network all devices must provided link-local
   address MUST be securely identified
   and authorized advertised on the local link using proxy neighbour
   discovery.  The Join Proxy MAY limit forwarded traffic to join the domain.

   A Registrar accepts or declines a request
   protocol (6 and 17) and port numbers indicated by locator1 and
   locator2.  The address to join which the domain, based
   on IPIP traffic should be sent is
   the authenticated identity presented.  Automated acceptance
   criteria include:

   o  allow any device initiator address (an ACP address of a specific type (as determined by the X.509
      IDevID),

   o  allow any device from a specific vendor (as determined by Registrar), not the
      X.509 IDevID),

   o  allow a specific device from a vendor (as determined by
   address given in the X.509
      IDevID) against a domain white list.  (The mechanism for checking
      a shared white list potentially used by multiple locator.

   Registrars is out MUST accept TCP / UDP traffic on the ports given at the
   ACP address of scope).

   To look the Pledge up in a domain white list a consistent method for
   extracting device identity from Registrar.  If the X.509 certificate is required.
   RFC6125 describes Domain-Based Application Service identity but here
   we require Vendor Device-Based identity.  The subject field's DN
   encoding Registrar supports IPIP
   tunnelling, it MUST include the "serialNumber" attribute also accept traffic encapsulated with IPIP.

   Registrars MUST accept HTTPS/EST traffic on the device's
   unique serial number.  In TCP ports indicated.
   Registrars MAY accept DTLS/CoAP/EST traffic on the language of RFC6125 this provides for a
   SERIALNUM-ID category of identifier that can be included UDP in addition to
   TCP traffic.

3.2.  Request Voucher from the Registrar

   When the Pledge bootstraps it makes a
   certificate and therefore that can also be used request for matching
   purposes. a Voucher from a
   Registrar.

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

   The SERIALNUM-ID whitelist request is collated according to vendor
   trust anchor since serial numbers are not globally unique. itself a voucher [I-D.ietf-anima-voucher].  The Registrar Pledge
   populates the voucher fields as follows:

   assertion:  The voucher request MUST use contain an assertion of
      "proximity".  [[EDNOTE: this is a placeholder as this commit is
      not the vendor provided MASA service correct place to verify
   that expand this list.  Using proximity and
      channel binding: if both the Pledge and the device's history log does not include unexpected Registrars.
   If a device had previously registered with another domain, a Registrar of that domain would show sign the
      channel binding statement then these provide vital proximity
      information to the MASA.  To be expanded on in a future commit.]]

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

   nonce:  The authorization performed during BRSKI voucher request MUST contain a cryptographically strong
      random or pseudo-random number nonce.  Doing so ensures
      Section 2.4 functionality.  The nonce MUST NOT be reused for
      multiple bootstrapping attempts.

   All other fields MAY be used ommitted in a voucher request.  [[EDNOTE: An
   issue has been created for EST
   enrollment requests by proceeding with EST enrollment using the
   authenticated and authorized TLS connection.  This minimizes the
   number of cryptographic and protocol operations necessary voucher document to complete
   bootstraping of ensure normative
   language supports this]]

   Signing the local key infrastructure.

3.3.3.  Claiming request is RECOMMENDED if the New Entity

   Claiming an entity establishes an audit log at Pledge has sufficient
   processing to perform the crypto operations.  Doing so allows the MASA server and
   provides a
   Registrar with proof, in and MASA to confirm the form "proximity" assertion of the Voucher, that
   Pledge.

   Request media type: application/voucherrequest

   An example JWS payload of the
   log entry has been inserted.  As indicated in Section 3.1.4 a Pledge
   will only proceed with bootstrapping if a Voucher has been received. voucher request:

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

   [[EDNOTE: The Pledge therefore enforces that bootstrapping only occurs if the
   claim has been logged.  There is no requirement move to JWT allows for the vendor relatively simple signing
   operations.  One possibility here is to
   definitively know that carry the device is owned by original signed JWT
   as an optional part of the Registrar.

   The Registrar obtains payload sent to the MASA URI via static configuration or by
   extracting it from the X.509 IDevID credential.  See Section 2.3.

   During initial bootstrapping the Pledge provides (e.g. "original
   request"). this would be a nonce specific BRSKI addition to the particular bootstrapping attempt. voucher?]]

   The Registrar SHOULD include
   this nonce when claiming validates the Pledge from client identity as described in EST
   [RFC7030] section 3.3.2.  The registrar performs authorization as
   detailed in Section 3.3.2.  If authorization is successful the MASA service.  Claims
   from an unauthenticated
   Registrar are only serviced by obtains an Voucher from the MASA
   resource if a nonce is provided. service (see Section 3.3).

   The received voucher request is forwarded to the Pledge.

3.3.  Request Voucher from MASA

   A Registrar can claim requests a Pledge that is not online by forming Voucher from the
   request MASA service using the entities unique identifier and not including a
   nonce in the claim request.  Vouchers obtained in REST
   interface.  For simplicity this way do not
   have is defined as an optional EST message
   between a lifetime Registrar and they provide a permanent method for an EST server running on the domain to
   claim MASA service
   although the device.  Evidence of such a claim Registrar is provided in the audit
   log entries available not required to make use of any future Registrar.  Such claims reduce
   the ability for future domains to secure bootstrapping and therefore
   the Registrar MUST be authenticated by other EST
   functionality when communicating with the MASA service.  (The MASA
   service although no MUST properly reject any EST functionality requests it does
   not wish to service; a requirement is implied that the MASA associates this authentication holds for any REST
   interface).

   This is done with ownership.

   An Ownership Voucher requires an HTTP POST using the vendor to definitively know that a
   device is owned by a specific domain. operation path value of
   "/requestvoucher".

   Request media type: application/voucherrequest+cms

   The method used to "claim"
   this are out-of-scope.  A MASA ignores or reports failures when an
   attempt request format is made to claim a device that has a an Ownership Voucher.

3.3.4.  Log Verification

   A Registrar requests JSON object optionally containing the log nonce
   value (as obtained from the bootstrap request) and the X.509 IDevID
   extracted serial number (the full certificate is not needed and no
   proof-of-possession information for the Pledge device identity is included).
   The AuthorityKeyIdentifier value from the MASA
   service.  The log certificate is verified included to confirm that
   ensure a statistically unique identity.  The Pledge's serial number
   is extracted from the following X.509 IDevID.  See Section 2.2.

   {
     "ietf-voucher:voucher": {
       "nonce": "62a2e7693d82fcda2624de58fb6722e5",
       "created-on": "2017-01-01T00:00:00.000Z",
       "assertion": "proximity"
       "device-identifier-aki": "[[EDNOTE:authority key identifier field
       from the IDevID. Voucher draft text that device-identifier is true
   to "A
       unique identifier (e.g., serial number) within the satisfaction scope of the
       MASA" is insufficient because it prevents vendors from sharing
       a Registrar's configured policy:

   o  Any nonceless entries in MASA]]"
       "device-identifier": "JADA123456789"
     }
   }

   A Registrar MAY exclude the log are associated with domainIDs
      recognized by nonce from the registrar.

   o  Any nonce'd entries are older than when request.  Doing so allows
   the domain is known Registrar to
      have physical possession of request a Voucher when the Pledge is not online, or that
   when the domainIDs are
      recognized by target bootstrapping environment is not on the registrar.

   If any of these criteria are unacceptable to a Registrar same network
   as the MASA server (this requires the entity
   is rejected.  A Registrar MAY be configured to ignore learn the history of
   appropriate DevIDSerialNumber field from the physical device but it is RECOMMENDED that labeling
   or from the sales channel -- how this only be configured if
   hardware assisted NEA [RFC5209] occurs is supported.

   This document specifies out-of-scope of this
   document).  If a simple log format as nonce is not provided by the MASA
   service to server MUST
   authenticate the registar.  This format could be improved by
   distributed consensus technologies that integrate vouchers with a
   technologies such Registrar as block-chain or hash trees or the like.  Doing so
   is out of described in EST [RFC7030] section
   3.3.2 to reduce the scope risk of this document but DDoS attacks.  The MASA performs
   authorization as detailed in Appendix D.1.3.2.

   As described in [I-D.ietf-anima-voucher] vouchers are anticipated improvements normally short
   lived to avoid revocation issues.  If the request is for future work.

3.4.  Behavior of a previous
   (expired) voucher using the same Registrar (as determined by
   Registrar's' domainID) and the MASA Service

   The Manufacturer Authorized Signing Authority service has not been informed that the
   claim is directly
   provided by invalid - the manufacturer, or can be provided by request for a third party the
   manufacturer authorizes.  It renewed voucher SHOULD be
   automatically authorized.  If authorization is successful the MASA
   responds with a cloud resource. [I-D.ietf-anima-voucher] voucher.  The MASA service
   provides SHOULD
   check for revocation of the following functionalities to Registrars:

   Issue Vouchers:  In response to Registrar requests certificate.  The maximum
   lifetime of the MASA service
      issues vouchers.  Depending on voucher issued SHOULD NOT exceed the MASA policy lifetime of the
   Registrar's revocation validation (for example if the Registrar claim
      of device ownership
   revocation status is either accepted or verified using out-of-
      scope methods (that are expected to improve over time).

   Log Vouchers Issued:  When indicated in a voucher CRL that is issued valid for two weeks
   then that is an appropriate lifetime for the act of issuing it
      includes updating voucher).

   The voucher request is signed by the certifiable logs.  Future work Registrar as indicated in
   [I-D.ietf-anima-voucher] voucher.  The entire certificate chain, up
   to enhance and distribute these logs is out-of-scope but expected over time.

   Provide Logs:  As a baseline implementation of the certified logging
      mechanism including the MASA is repsonsible for reporting logged
      information. Domain CA, MUST be included.  The current method involves trusting MASA service
   checks the MASA.
      Other logging methods where internal consistency of the MASA voucher request but does not
   authenticate the domain identity information since the domain is less trusted are expected not
   know to be developed over time.

3.5.  Leveraging the new key infrastructure / next steps

   As MASA server in advance.  The MASA server MUST verify that
   the devices have voucher request is signed by a common trust anchor, device identity Registrar certificate (by checking
   for the cmc-idRA field) that was issued by the self signed root
   certificate included in the request.  [[ EDNOTE: can be
   securely established, we simplify the
   above sentence? ]] This ensures that the Registrar making it possible to automatically deploy
   services across the domain in a secure manner.

   Examples claim
   is an authorized Registrar of services:

   o  Device management.

   o  Routing authentication.

   o  Service discovery.

3.5.1.  Network boundaries

   When a device has joined the domain, it can validate unauthenticated domain.

   The root certificate is extracted and used to populate the Voucher.
   The domain
   membership ID (e.g. hash of other devices.  This makes it possible to create trust
   boundaries where domain members have higher level the public key of trusted than
   external devices.  Using the autonomic User Interface, specific
   devices can be grouped into to sub domains and specific trust levels
   can be implemented between those.

3.6.  Interactions with Network Access Control

   The assumption domain) is that Network Access Control (NAC) completes using
   the Pledge 's X.509 IDevID credentials and results in
   extracted from the device
   having sufficient connectivity to discovery root certificate and communicate with the
   proxy.  Any additional connectivity or quarantine behavior by the NAC
   infrastructure is out-of-scope.  After the devices has completed
   bootstrapping the mechanism used to trigger NAC update the audit
   log.

3.4.  Voucher Response

   The voucher response to re-authenticate requests from the device and provide updated network privileges is also out-of-scope.

   This achieves requests from a
   Registrar are in the goal of same format.  A Registrar either caches prior
   MASA responses or dynamically requests a bootstrap architecture that can integrate
   with NAC but does not require NAC within new Voucher based on local
   policy.

   If the network where it wasn't
   previously required.  Future optimizations can be achieved by
   integrating the bootstrapping protocol directly into an initial EAP
   exchange.

4.  Domain Operator Activities

   This section describes how join operation is successful, the server response MUST
   contain an operator interacts HTTP 200 response code.  The server MUST answer with a domain that
   supports
   suitable 4xx or 5xx HTTP [RFC2616] error code when a problem occurs.
   The response data from the bootstrapping as MASA server MUST be a plaintext human-
   readable (ASCII, english) error message containing explanatory
   information describing why the request was rejected.

   Response media type: application/voucher+cms

   The syntactic details of vouchers are described in this document.

4.1.  Instantiating detail in
   [I-D.ietf-anima-voucher].  For example, the Domain Certification Authority

   This is a one time step by voucher consists of:

   {
     "ietf-voucher:voucher": {
       "nonce": "62a2e7693d82fcda2624de58fb6722e5",
       "assertion": "logging"
       "trusted-ca-certificate": "<base64 encoded certificate>"
       "device-identifier": "JADA123456789"
     }
   }

   The Pledge verifies the domain administrator.  This is an "off signed voucher using the shelf" CA manufacturer
   installed trust anchor associated with the exception that it is designed to work as an
   integrated part vendor's selected
   Manufacturer Authorized Signing Authority.

   The 'trusted-ca-certificate' element of the security solution.  This precludes voucher contains the use of
   3rd party certification authority services that do not provide
   support for delegation of certificate issuance decisions to a
   domain
   managed Registration Authority.

4.2.  Instantiating the Registrar CA's public key.  This is useful for bootstrapping a one time step by the public
   key infrastructure but to support bootstrapping other key
   infrastructures additional domain administrator.  One or more
   devices identity types might be defined in
   the domain are configured take on a Registrar function.

   A device can future.

   The pledge's EST clients MUST be configured to act as a Registrar or a device can
   auto-select itself prepared to take on this function, using a detection
   mechanism ignore additional fields
   they do not recognize.

   the pledge MUST be prepared to resolve potential conflicts parse and setup communication with
   the Domain Certification Authority.  Automated Registrar selection is
   outside scope for this document.

4.3.  Accepting New Entities

   For each fail gracefully from an
   Voucher response that does not contain a 'trusted-ca-certificate'
   field at all.

   The Pledge MUST use the Registrar is informed 'trusted-ca-certificate' trust anchor to
   immediately complete authentication of the unique identifier
   (e.g. serial number) along with the manufacturer's identifying
   information (e.g. manufacturer root certificate).  This provisional TLS
   connection.

3.4.1.  Completing authentication of Provisional TLS connection

   If a Registrar's credentials can happen in
   different ways:

   1.  Default acceptance: In not be verified using the simplest case, trusted-
   ca-certificate trust anchor from the new device asserts
       its unique identity voucher then the TLS connection
   is immediately discarded and the Pledge abandons attempts to a Registrar.
   bootstrap with this discovered registrar.  The registrar accepts all
       devices without authorization checks.  This mode does not provide
       security against intruders and is not recommended.

   2.  Per device acceptance: pledge SHOULD send
   voucher status telemetry (described below) before closing the TLS
   connection.  The new device asserts its unique identity pledge MUST attempt to a Registrar.  A non-technical human validates the identity,
       for example by comparing the identity displayed by the registrar
       (for example enroll using a smartphone app) with the identity shown on any other
   proxies it has found.  It SHOULD return to the packaging of same proxy again after
   attempting with other proxies.  Attempts should be attempted in the device.  Acceptance
   exponential backoff described earlier.  Attempts SHOULD be repeated
   as failure may be triggered by a
       click on the result of a smartphone app "accept this device", temporary inconsistently (an
   inconsistently rolled Registrar key, or by some other forms
       of pairing.  See mis-
   configuration).  The inconsistently could also [I-D.behringer-homenet-trust-bootstrap] for
       how be the approach could work in a homenet.

   3.  Whitelist acceptance: In larger networks, neither of result an
   active MITM attack on the previous
       approaches is acceptable.  Default acceptance is not secure, and
       a manual per device methods do not scale.  Here, EST connection.

   To ensure that the registrar trusted-ca-certificate provide chain is
       provided a priori with able to
   verify, the Registrar MUST use a list of identifiers of devices certificate that
       belong chains to the network.  This list can be extracted from an
       inventory database, or sales records.  If
   trusted-ca-certificate.

   The Pledge's PKIX path validation of a device Registrar certificate's
   validity period information is detected as described in Section 2.4.  Beyond
   that once PKIX path validation is not on successful the list of known devices, it TLS connection is no
   longer provisional.

   The trusted-ca-certificate is installed as an Explicit Trust Anchor
   for future operations.  It can therefore can still be
       manually accepted using the per device acceptance methods.

   4.  Automated Whitelist: an automated process used to authenticate
   any dynamically discovered EST server that builds the
       necessary whitelists and inserts them into contain the larger network
       domain infrastructure is plausible.  Once set up, no human
       intervention is required id-kp-cmcRA
   extended key usage extension as detailed in this process.  Defining EST RFC7030 section
   3.6.1; but to reduce system complexity the exact
       mechanisms for this is out of scope although Pledge SHOULD avoid
   additional discovery operations.  Instead the registrar
       authorization checks is identified Pledge SHOULD
   communicate directly with the Registrar as the logical integration
       point of any EST server for future work in this area.

   None
   key management operations.  The 'trusted-ca-certificate' is not a
   complete distribution of these approaches require the network to have permanent
   Internet connectivity.  Even when the Internet based MASA service EST section 4.1.3 CA Certificate
   Response which is
   used, it an additional justification for the recommendation
   to proceed with EST key management operations.

3.5.  Voucher Status Telemetry

   The domain is possible expected to provide indications to pre-fetch the required information from the
   MASA a priori, for example at time of purchase such that devices can
   enroll later.  This supports use cases where the domain network may
   be entirely isolated during system
   administrators concerning device deployment.

   Additional policy can be stored for future authorization decisions.
   For example an expected deployment time window or that a certain
   Proxy must be used.

4.4.  Automatic Enrollment of Devices

   The approach outlined in lifecycle status.  To facilitate
   this document provides a secure zero-touch
   method to enroll new devices without any pre-staged configuration.
   New devices communicate with already enrolled devices of it needs telemetry information concerning the domain,
   which proxy between device's status.

   To indicate Pledge status regarding the new device and a Registrar.  As a result of
   this completely automatic operation, all devices obtain Voucher the client SHOULD
   post a domain
   based certificate.

4.5.  Secure Network Operations status message.

   The certificate installed in posted data media type: application/json

   The client HTTP POSTs the previous step can be used for all
   subsequent operations.  For example, following to determine the boundaries of server at the domain: If a neighbor has a certificate from EST well
   known URI /voucher_status.  The Status field indicates if the same trust
   anchor Voucher
   was acceptable.  If it can be assumed "inside" was not acceptable the same organization; if not, as
   outside.  See also Section 3.5.1.  The certificate can also be used Reason string indicates
   why.  In the failure case this message is being sent to securely establish a connection between devices an
   unauthenticated, potentially malicious Registrar and central
   control functions.  Also autonomic transactions can use therefore the domain
   certificates to authenticate and/or encrypt direct interactions
   between devices.
   Reason string SHOULD NOT provide information beneficial to an
   attacker.  The usage operational benefit of the domain certificates this telemetry information is outside
   scope for
   balanced against the operational costs of not recording that an
   Voucher was ignored by a client the registar expected to continue
   joining the domain.

   [[EDNOTE: the server can know which pledge failed by the previous
   voucher, I think.  Is this document.

5.  Proxy Discovery Protocol Details worth noting?]]
   {
     "version":"1",
     "Status":FALSE /* TRUE=Success, FALSE=Fail"
     "Reason":"Informative human readable message"
   }

   The proxy uses server SHOULD respond with an HTTP 200 but MAY simply fail with
   an HTTP 404 error.  The client ignores any response.  Within the GRASP M_FLOOD mechanism to announce itself.
   server logs the server SHOULD capture this telemetry information.

3.6.  MASA authorization log Request

   A registrar requests 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
   announcement is done with an HTTP GET using the operation path value of
   "/requestauditlog".

   The client MUST HTTP POSTs the same message Voucher Request as for requesting
   a Voucher.  It is posted to the ACP announcement
   detailed in [I-D.ietf-anima-autonomic-control-plane].

     proxy-objective = ["Proxy", [ O_IPv6_LOCATOR, ipv6-address,
                                   transport-proto, port-number ] ]

     ipv6-address       - /requestauditlog URI instead.  The
   IDevIDAuthorityKeyIdentifier and DevIDSerialNumber informs the v6 LL of MASA
   server which log is requested so the proxy
     transport-proto    - 6, for TCP 17 appropriate log can be prepared
   for UDP
     port-number        - the TCP or UDP port number to find response.  Using the proxy

   Figure 5

6.  Registrar Discovery Protocol Details

   The registrar responds to discovery messages from the proxy (or GRASP
   caches between them) as follows: (XXX changed from M_DISCOVERY)

   objective         = ["AN_registrar", F_DISC, 255 ]
   discovery-message = [M_NEG_SYN, session-id, initiator, objective]

   Figure 6: Registrar Discovery same media type and message minimizes
   cryptographic and message operations although it results in
   additional network traffic.  The response from the registrar (or cache) will be a M_RESPONSE relying MASA server implementation
   MAY leverage internal state to associate this request with the following parameters:

   response-message = [M_RESPONSE, session-id, initiator, ttl,
                      (+locator-option // divert-option), ?objective)]
   initiator = ACP address of Registrar
   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]

   Figure 7: Registrar Response

   The set of locators is to be interpreted
   original, and by now already validated, voucher request so as follows. to
   avoid an extra crypto validation.

   Request media type: application/voucherrequest+cms

3.7.  MASA authorization log Response

   A protocol of 6
   indicates that TCP proxying on the indicated port log data file is desired.  A
   protocol returned consisting of all log entries.  For
   example:

  {
    "version":"1",
    "events":[
      {
       "date":"<date/time of 17 indicates that UDP proxying on the indicated port is
   desired.  In each case, the traffic SHOULD be proxied to entry>",
       "domainID":"<domainID as extracted from the same
   port at domain CA certificate
                    within the ULA address provided.

   A protocol CMS of 41 indicates that packets may be IPIP proxy'ed.  The
   address in the locator In audit voucher request>",
       "nonce":"<any nonce if supplied (or the case exact string 'NULL')>"
      },
      {
       "date":"<date/time 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 entry>",
       "domainID":"<domainID as extracted from the IPIP
   traffic should be sent is domain CA certificate
                    within the initiator address (an ACP address CMS of the Registrar), not the address given in audit voucher request>",
       "nonce":"<any nonce if supplied (or the locator. exact string 'NULL')>"
      }
    ]
  }

   Distribution of a large log is less than ideal.  This structure can
   be optimized as follows: All nonce-less entries for the same domainID
   MAY be condensed into the single most recent nonceless entry.

   A Registrar MUST accept TCP / UDP traffic on SHOULD use this log information to make an informed
   decision regarding the ports given at continued bootstrapping of the
   ACP address Pledge.  For
   example if the log includes unexpected domainIDs this is indicative
   of problematic imprints by the Registrar. Pledge.  If the Registrar supports IPIP
   tunnelling, it MUST also accept traffic encapsulated with IPIP.

   Registrars MUST accept HTTPS/EST traffic on log includes nonce-
   less entries this is indicative of the ports indicated.
   Registrars MAY accept DTLS/CoAP/EST traffic in addition.

7.  Protocol Details

   A bootstrapping protocol could be implemented as an independent
   protocol from EST, but permanent ability for simplicity and to reduce the number
   indicated domain to trigger a reset of TLS
   connections and crypto operations required on the Pledge, it device and take over
   management of it.  Equipment that is
   described specifically as extensions to EST.  These extensions MUST purchased pre-owned can be supported by the
   expected to have an extensive history.  A Registrar EST server within the same .well-known
   URI tree as the existing EST URIs as described in EST [RFC7030]
   section 3.2.2.

   A MAY request logs
   at future times [[EDNOTE: we need to ensure MASA URI server is therefore "https:// authority "./well-known/est".  The
   portion contained in not
   slammed with too many requests]].  A Registrar MAY be configured to
   ignore the IDevID extension is only
   "https://example.com" since everything after that is well known.

   Establishment history of the TLS connection for bootstrapping device but it is as specified
   for EST [RFC7030].  In particular server identity and client identity
   are as described in EST [RFC7030] section 3.3.  In EST [RFC7030]
   provisional server authentication for bootstrapping RECOMMENDED that this only
   be configured if hardware assisted NEA [RFC5209] is described in
   section 4.1.1 wherein EST clients supported.

   Log entries containing the Domain's ID can "engage be compared against local
   history logs in search of discrepancies.

   This document specifies a human user simple log format as provided by the MASA
   service to
   authorize the CA certificate using out-of-band data registar.  This format could be improved by
   distributed consensus technologies that integrate vouchers with a
   technologies such as a CA
   certificate" block-chain or hash trees or wherein a human user configures the URI like.  Doing so
   is out of the EST
   server for Implicit TA based authentication.  This documented
   establishes automated methods scope of authorizing the CA certificate using
   in-band vouchers.

   If the Pledge uses a well known URI this document but are anticipated improvements
   for contacting a well known
   Registrar 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.

3.8.  EST Implicit Trust Anchor database is used Integration for PKI bootstrapping

   This section describes EST extensions necessary to
   authenticate enable fully
   automated bootstrapping.  Although the well known URI.  In this case Voucher request/response
   structure members IDevIDAuthorityKeyIdentifier and DevIDSerialNumber
   are specific to PKI bootstrapping these are the connection is not
   provisional only PKI specific
   aspects of the extensions and RFC6125 methods can be used future work might replace them with
   non-PKI structures.

   Once the Voucher is received, as specified in this document, the
   client has sufficient information to authenticate leverage the existing
   communication channel with a Registrar to continue an EST RFC7030
   enrollment.  The Pledge establishes a TLS connection with the Registrar through
   the circuit proxy (see Section 3.2) but SHOULD use the existing current TLS
   connection is to proceed with EST enrollment, thus reducing the Registar; so for this section the "Pledge" is the TLS client total
   amount of cryptographic and round trip operations required during
   bootstrapping (enrollment picks up after EST RFC7030 "Bootstrap
   Distribution of CA Certificates" and the "Registrar" is the TLS server.

   The extensions for the Pledge client are as follows:

   o continues with EST
   enrollment operations including "CA Certificates Request", "CSR
   Attributes" and "Client Certificate Request" or "Server-Side Key
   Generation").

   The Pledge provisionally accept is RECOMMENDED to implement the following EST server certificate during automation
   extensions.  They supplement the TLS handshake as detailed RFC7030 EST to better support
   automated devices that do not have an end user.

   [[EDNOTE:might be best to discuss in Section 7.3.1.

   o CSR attributes?]]For the
   purposes of creating the ANIMA Autonomic Control Plane, the contents
   of the new certificate MUST be carefully specified.
   [I-D.ietf-anima-autonomic-control-plane] section 5.1.1 contains
   details.  The Pledge requests and validates Registrar MUST provide the Voucher as described below.
      At this point the Pledge has sufficient correct ACP information
   to validate
      domain credentials.

   o populate the subjectAltName / rfc822Name field in the "CSR
   Attributes" step.

3.8.1.  EST Distribution of CA Certificates

   The Pledge calls MUST request the full EST defined /cacerts method to obtain Distribution of CA Certificates
   message.  See RFC7030, section 4.1.

   This ensures that the Pledge has the complete set of current CA certificate.  These are validated using
   certificates beyond the Voucher.

   o  The Pledge completes bootstrapping as detailed in EST section
      4.1.1.

   In order to obtain domainCAcert (see Section 3.4 for a Voucher and associated logs
   discussion of the limitations).  Although these restrictions are
   acceptable for a Registrar contacts integrated with initial bootstrapping they
   are not appropriate for ongoing PKIX end entity certificate
   validation.

3.8.2.  EST CSR Attributes

   Automated bootstrapping occurs without local administrative
   configuration of the MASA service Service using REST calls:

              +-----------+ +----------+ +-----------+ +----------+
              | New       | | Circuit  | |           | |          |
              | Entity    | | Proxy    | | Registrar | | Vendor   |
              |           | |          | |           | |          |
              ++----------+ +--+-------+ +-----+-----+ +--------+-+
               |               |               |                |
               |               |               |                |
               |   TLS hello   |  TLS hello    |                |
   Establish   +---------------C--------------->                |
   TLS         |               |               |                |
   connection  |               | Server Cert   |                |
               <---------------C---------------+                |
               | Client Cert   |               |                |
               +---------------C--------------->                |
               |               |               |                |
   HTTP REST   | POST /requestvoucher          |                |
   Data        +--------------------nonce------>                |
               |               .               | /requestvoucher|
               |               .               +---------------->
               |                               <----------------+
               |                               | /requestlog    |
               |                               +---------------->
               |            voucher            <----------------+
               <-------------------------------+                |
               | (optional config information) |                |
               |               .               |                |
               |               .               |                |

   Figure 8 Pledge.  In some use cases deployments its plausible that
   the Registrar may need Pledge generates a certificate request containing only identity
   information known to contact the Vendor in
   advanced, for example when Pledge (essentially the target network is air-gapped.  The
   nonceless request format is provided for this X.509 IDevID
   information) and ultimately receives a certificate containing domain
   specific identity information.  Conceptually the resulting flow CA has complete
   control over all fields issued in the end entity certificate.
   Realistically this is slightly different.  The security differences associated operationally difficult with not
   knowing the nonce are discussed below:

              +-----------+ +----------+ +-----------+ +----------+
              | New       | | Circuit  | |           | |          |
              | Entity    | | Proxy    | | Registrar | | Vendor   |
              |           | |          | |           | |          |
              ++----------+ +--+-------+ +-----+-----+ +--------+-+
               |               |               |                |
               |               |               |                |
               |               |               | /requestvoucher|
               |               |  (nonce       +---------------->
               |               |  unknown)     <----------------+
               |               |               | /requestlog    |
               |               |               +---------------->
               |               |               <----------------+
               |   TLS hello   |  TLS hello    |                |
   Establish   +---------------C--------------->                |
   TLS         |               |               |                |
   connection  |               | Server Cert   |                |
               <---------------C---------------+                |
               | Client Cert   |               |                |
               |               |               |                |
   HTTP REST   | POST /requestvoucher          |                |
   Data        +----------------------nonce---->   (discard     |
               |            voucher            |   nonce)       |
               <-------------------------------+                |
               | (optional config information) |                |
               |               .               |                |
               |               .               |                |

   Figure 9

   The extensions for current status
   of PKI certificate authority deployments where the CSR is submitted
   to the CA via a Registrar server are as follows:

   o  The Registrar requests and validates number of non-standard protocols.

   To alleviate operational difficulty the Voucher Pledge MUST request the EST
   "CSR Attributes" from the vendor
      authorized MASA service.

   o  The Registrar forwards EST server.  This allows the Voucher local
   infrastructure to inform the Pledge when requested.

   o  The Registar performs log verifications in addition of the proper fields to local
      authorization checks before accepting include
   in the Pledge device. generated CSR.

   [[EDNOTE: The provisional TLS connection introduces security risks that are
   addressed following is specific to anima purposes and should be
   moved to an appropriate anima document so as follows:

   If the Registrar provides a redirect response the Pledge MUST follow
   the redirect but the connection remains provisional.  The Pledge MUST
   only follow to keep bootstrapping as
   generic as possible: What we want are a single redirection.

   The Registar MAY respond with 'domain name' stored in [TBD]
   and an HTTP 202 ("the request has been
   accepted for processing, but 'ACP IPv6 address' stored in the processing has not been completed") iPAddress field as described specified
   in EST [RFC7030] section 4.2.3 wherein RFC5208 s4.2.1.6. ref ACP draft where certificate verification
   [TBD].  These should go into the client "MUST
   wait at least subjectaltname in the specified 'retry-after' time before repeating [TBD]
   fields.]].  If the
   same request".  The Pledge hardwareModuleName in the X.509 IDevID is RECOMMENDED
   populated then it SHOULD by default be propagated to provide the LDevID along
   with the hwSerialNum.  The registar SHOULD support local feed
   (blinked LED etc) during this wait cycle if mechanisms for policy
   concerning this are
   available.  To prevent functionality.  [[EDNOTE: extensive use of EST CSR
   Attributes might need an attacker Registrar from significantly
   delaying bootstrapping the Pledge new OID definition]].]]

   The Registar MUST limit also confirm the 'retry-after' time resulting CSR is formatted as
   indicated before forwarding the request to 60 seconds.  To avoid waiting on a single erroneous Registrar CA.  If the
   Pledge MUST drop Registar is
   communicating with the connection after 5 seconds and proceed CA using a protocol like full CMC which
   provides mechanisms to other
   discovered Registrars.  Ideally override the Pledge could keep track of CSR attributes, then these
   mechanisms MAY be used even if the
   appropriate retry-after value for any number of outstanding
   Registrars but this would involve client ignores CSR Attribute
   guidance.

3.8.3.  EST Client Certificate Request

   The Pledge MUST request a large state table on new client certificate.  See RFC7030,
   section 4.2.

3.8.4.  Enrollment Status Telemetry

   For automated bootstrapping of devices the Pledge.
   Instead adminstrative elements
   providing bootstrapping also provide indications to the Pledge MAY ignore system
   administrators concerning device lifecycle status.  This might
   include information concerning attempted bootstrapping messages seen
   by the exact retry-after value in favor client, MASA provides logs and status of credential
   enrollment.  The EST protocol assumes an end user and therefore does
   not include a single hard coded value that takes effect between discovery
   (Section 3.1.1) attempts.  A Registrar that is unable to complete the
   transaction the first time due final success indication back to timing reasons will have future
   chances.

7.1.  Request Voucher from the Registrar

   When the Pledge bootstraps it makes a request for a Voucher from a
   Registrar. server.  This is done with an HTTPS POST
   insufficient for automated use cases.

   To indicate successful enrollment the client SHOULD re-negotiate the
   EST TLS session using the operation path value of
   "/requestvoucher".

   The request format is JSON object containing a 64bit nonce generated newly obtained credentials.  This occurs by
   the client for each request.  This nonce MUST be initiating a
   cryptographically strong random or pseudo-random number that can not
   be easily predicted. new TLS ClientHello message on the existing
   TLS connection.  The nonce MUST NOT be reused for multiple
   attempts to join a network domain.  The nonce assures the Pledge that client MAY simply close the Voucher response is associated with this bootstrapping attempt old TLS session and is not
   start a replay.

   Request media type: application/voucherrequest

   Request format: new one.  The server MUST support either model.

   In the case of a JSON file with FAIL the following:

   {
    "version":"1",
    "nonce":"<64bit nonce value>",
   }

   [[EDNOTE: Even Reason string indicates why the most recent
   enrollment failed.  The SubjectKeyIdentifier field MUST be included
   if the nonce enrollment attempt was signed it would provide no defense
   against rogue registrars; although it would assure the MASA that a
   certified Pledge exists.  To protect against rogue registrars for a nonce
   component generated by the MASA (a new round trip) would be
   required).  Instead this is addressed by requiring MASA & Registrar
   authentications but it keypair that is worth exploring additional protections.
   This locally known to be explored more at IETF96.]]

   The Registrar validates
   the client identity as described in EST
   [RFC7030] section 3.3.2.  The registrar performs authorization as
   detailed in Section 3.3.2. client.  If authorization is successful EST /serverkeygen was used and failed then the
   Registrar obtains an Voucher field
   is omitted from the MASA service (see Section 5.2).

   The received Voucher is forwarded to status telemetry.

   In the Pledge.

7.2.  Request Voucher from MASA

   A Registrar requests case of a Voucher from SUCCESS the MASA service using a REST
   interface.  For simplicity this Reason string is defined as an optional EST message
   between a Registrar and an EST omitted.  The
   SubjectKeyIdentifier is included so that the server running on can record the MASA service
   although
   successful certificate distribution.

   Status media type: application/json

   The client HTTP POSTs the Registrar is not required following to make use of any other EST
   functionality when communicating with the MASA service.  (The MASA
   service MUST properly reject any server at the new EST functionality requests it does
   not wish to service; a requirement that holds well
   known URI /enrollstatus.

  {
    "version":"1",
    "Status":TRUE /* TRUE=Success, FALSE=Fail"
    "Reason":"Informative human readable message"
    "SubjectKeyIdentifier":"<base64 encoded subjectkeyidentifier for any REST
   interface).

   This is done the
                             enrollment that failed>"
  }

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

   Within the operation path value of
   "/requestvoucher".

   Request media type: application/voucherrequest+cms

   The request format is server logs the server MUST capture if this message was
   received over an TLS session with a JSON object optionally containing matching client certificate.
   This allows for clients that wish to minimize their crypto operations
   to simply POST this response without renegotiating the nonce
   value (as obtained from TLS session -
   at the bootstrap request) and cost of the X.509 IDevID
   extracted serial number (the full certificate is server not needed and no
   proof-of-possession information for the device identity is included).
   The AuthorityKeyIdentifier value from the certificate is included being able to
   ensure a statistically unique identity.  The Pledge's serial number
   is extracted from the X.509 IDevID.  See Section 2.3.

   {
   "version":"1",
   "nonce":"<64bit nonce value>",
   "IDevIDAuthorityKeyIdentifier":"<base64 encoded keyIdentifier">,
   "DevIDSerialNumber":"<id-at-serialNumber or base64 encoded
   hardwareModuleName hwSerialNum>",
   }

   A Registrar MAY exclude accurately verify that
   enrollment was truly successful.

3.8.5.  EST over CoAP

   [[EDNOTE: In order to support smaller devices the nonce from above section on
   Proxy behavior introduces mandatory to implement support for CoAP
   support by the request.  Doing so allows Proxy.  This implies similar support by the Pledge and
   Registrar to request a Voucher when and means that the Pledge is not online, or
   when the target bootstrapping environment is not on the same network
   as the MASA server (this requires the Registrar EST protocol operation encapsulation
   into CoAP needs to learn the
   appropriate DevIDSerialNumber field from the physical device labeling
   or from the sales channel -- how this occurs be described.  EST is out-of-scope HTTP based and "CoaP is
   designed to easily interface with HTTP for integration" [RFC7252].
   Use of CoAP implies Datagram TLS (DTLS) wherever this
   document).  If a nonce document
   describes TLS handshake specifics.  A complexity is not provided the MASA server MUST
   authenticate the Registrar as described in EST [RFC7030] section
   3.3.2 to reduce that the risk large
   message sizes necessary for bootstrapping will require support for
   [draft-ietf-core-block].]]

4.  Reduced security operational modes

   A common requirement of DDoS attacks.  The MASA performs
   authorization as detailed in Section 3.3.2.

   As described in [I-D.ietf-anima-voucher] vouchers are normally short
   lived to avoid revocation issues.  If the request bootstrapping is to support less secure
   operational modes for a previous
   (expired) voucher using support specific use cases.  The following
   sections detail specific ways that the same Pledge, Registrar (as determined by
   domainID) and the MASA has not been informed that the claim is no
   longer valid - the request for a renewed voucher SHOULD can
   be
   automatically authorized.  If authorization is successful the MASA
   responds with configured to run in a [I-D.ietf-anima-voucher] voucher.  The MASA SHOULD
   check less secure mode 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 reasons.

4.1.  Trust Model

   +--------+         +---------+    +------------+     +------------+
   | New    |         | Circuit |    | Domain     |     | Vendor     |
   | Entity |         | Proxy   |    | Registrar  |     | Service    |
   |        |         |         |    |            |     | (Internet  |
   +--------+         +---------+    +------------+     +------------+

   Figure 10

   Pledge:  The Pledge could be compromised and providing an appropriate lifetime attack
      vector for the voucher). malware.  The voucher request is encapsulated in a [RFC5652] Signed-data that entity is signed by the Registrar.  The entire certificate chain, up trusted to and
   including the Domain CA, MUST be included only imprint using
      secure methods described in the CertificateSet
   structure.  The MASA service checks the internal consistency this document.  Additional endpoint
      assessment techniques are RECOMMENDED but are out-of-scope of the
   CMS this
      document.

   Proxy:  Provides proxy functionalities but does not authenticate the domain identity information.  The
   domain is not know to the MASA server involved in advance and
      security considerations.

   Registrar:  When interacting with a shared trust
   anchor is not implied.  The MASA server MUST verify that the CMS is
   signed by a Registrar certificate (by checking for the cmc-idRA
   field) that was issued by makes all
      decisions.  When Ownership Vouchers are involved a the root certificate included in the CMS.
   This ensures that the Registrar making the claim is an authorized Registrar of the unauthenticated domain.

   The root certificate is extracted
      only a conduit and used to populate the Voucher.
   The domain ID (e.g. hash of all security decisions are made on the public key vendor
      service.

   Vendor Service, MASA:  This form of the domain) vendor service is
   extracted from the root certificate trusted to
      accurately log all claim attempts and is used to update the audit
   log.

7.3.  Voucher Response

   The voucher response provide authoritative log
      information to requests from the device 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 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. Registrars.  The response data from the MASA server MUST be a plaintext human-
   readable error message containing explanatory information describing
   why the request was rejected.

   Response media type: application/voucher+cms

   The syntactic details of vouchers does not know which devices
      are described in detail in
   [I-D.ietf-anima-voucher].  For example, the voucher consists of:

   {
    "version":"1",
    "nonce":"<64bit nonce value>",
    "IDevIDAuthorityKeyIdentifier":"<base64 encoded keyIdentifier>",
    "DevIDSerialNumber":"<id-at-serialNumber>",
    "domainCAcert":"<the base64 encoded domain CA's certificate>"
   }

   The Voucher response is encapsulated in a [RFC5652] Signed-data that
   is signed by the MASA server.  The Pledge verifies this signed
   message using the manufacturer installed trust anchor associated with
   the X.509 IDevID.  [[EDNOTE: As detailed in netconf-zerotouch this
   might which domains.  These claims could be a distinct trust anchor rather than re-using the trust
   anchor
      strengthened by using cryptographic log techniques to provide
      append only, cryptographic assured, publicly auditable logs.
      Current text provides only for the IDevID. a trusted vendor.

   Vendor Service, Ownership Validation:  This concept will need to be detailed in this
   document as well.]]

   The 'domainCAcert' element form of this message contains the domain CA's
   public key.  This vendor service is specific
      trusted to bootstrapping a public key
   infrastructure.  To support bootstrapping other key infrastructures
   additional domain identity types might be defined in the future.
   Clients MUST be prepared to ignore additional fields they do not
   recognize.  Clients MUST be prepared to parse and fail gracefully
   from an Voucher response that does not contain a 'domainCAcert' field
   at all.

   To minimize the size of the Voucher response message the domainCAcert accurately know which device is not a complete distribution of the EST section 4.1.3 CA
   Certificate Response. owned by which domain.

4.2.  New Entity security reductions

   The Pledge installs the domainCAcert trust
   anchor.  As indicated in Section 3.1.2 the newly installed trust
   anchor MAY support "trust on first use" on physical interfaces
   but MUST NOT support "trust on first use" on network interfaces.
   This is used as an EST RFC7030 Explicit Trust Anchor. because "trust on first use" permanently degrades the
   security for all other use cases.

   The Pledge
   MUST use the domainCAcert trust anchor to immediately validate the
   currently provisional TLS connection to a Registrar.

7.3.1.  Completing authentication of Provisional TLS connection

   If MAY have an operational mode where it skips Voucher
   validation one time.  For example if a Registrar's credential physical button is depressed
   during the bootstrapping operation.  This can not be verified using the
   domainCAcert trust anchor useful if the TLS connection vendor
   service is immediately discarded
   and the Pledge abandons attempts unavailable.  This behavior SHOULD be available via local
   configuration or physical presence methods to bootstrap with ensure new entities can
   always be deployed even when autonomic methods fail.  This allows for
   unsecured imprint.

   It is RECOMMENDED that this discovered
   registrar.

   The following behaviors on a only be available if hardware assisted
   NEA [RFC5209] is supported.

4.3.  Registrar and Pledge are in addition to
   normal PKIX operations:

   o  The EST server 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 use a certificate that chains NOT be the default behavior:

   1.  A registrar MAY choose to accept all devices, or all devices of a
       particular type, at the
      domainCAcert. administrator's discretion.  This means that 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 EST server obtains renewed
      credentials benefit of authenticating that claimed
       identity.  This could occur when the credentials included in Pledge does not include an
       X.509 IDevID factory installed credential.  New Entities without
       an X.509 IDevID credential MAY form the Section 7.2 3.2 request
      match the chain used in using
       the current provisional TLS connection.

   o  The Pledge PKIX path validation of a Registrar validity period
      information is as described in Section 3.1.5.

   Because 3.3 format to ensure the domainCAcert trust anchor Pledge's serial number
       information is installed as an Explicit
   Trust Anchor it can be used provided 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 Registar (this includes the Pledge SHOULD avoid additional discovery
   operations.  Instead
       IDevIDAuthorityKeyIdentifier value which would be statically
       configured on the Pledge).  The Pledge SHOULD communicate directly with the
   Registrar as the EST server MAY refuse to complete PKI local provide a
       TLS client certificate
   enrollment.  Additionally the (as one is not available).  The Pledge
       SHOULD use the existing support HTTP-based or certificate-less TLS
   connection to proceed with authentication
       as described in EST enrollment, thus reducing the total
   amount of cryptographic and round trip operations required during
   bootstrapping.  [[EDNOTE: It is reasonable to mandate that the
   existing TLS connection be re-used? e.g. RFC7030 section 3.3.2.  A Registrar MUST >> SHOULD?]]

7.4.  Voucher Status Telemetry

   For automated bootstrapping of devices the adminstrative elements
   providing bootstrapping also provide indications NOT
       accept unauthenticated New Entities unless it has been configured
       to the system
   administrators concerning device lifecycle status.  To facilitate
   this those elements need telemetry information concerning the
   device's status.

   To indicate Pledge status regarding the Voucher the client SHOULD
   post do so by an administrator that has verified that only expected
       new entities can communicate with 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 Registrar (presumably via a
       physically secured perimeter).

   3.  A Registrar MAY request nonce-less Vouchers from the Voucher
   was acceptable.  If it was MASA service
       (by not acceptable including a nonce in the Reason string indicates
   why.  In request).  These Vouchers can
       then be transmitted to the failure case this message Registrar and stored until they are
       needed during bootstrapping operations.  This is being sent to for use cases
       where target network is protected by an
   unauthenticated, potentially malicious Registrar air gap 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 can
       not recording that an
   Voucher was ignored by a client contact the registar expected to continue
   joining the domain.

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

   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.

7.5. MASA authorization log Request service during Pledge deployment.

   4.  A registrar requests the MASA authorization MAY ignore unrecognized nonce-less log from the MASA service
   using this EST extension. entries.  This
       could occur when used equipment is done purchased with an HTTP GET using a valid history
       being deployed in air gap networks that required permanent
       Vouchers.

4.4.  MASA security reductions

   Lower security modes chosen by the operation path value of
   "/requestauditlog".

   The client MUST HTTP POSTs MASA service effect all device
   deployments unless bound to the same Voucher Request specific device identities.  In which
   case these modes can be provided as additional features for requesting specific
   customers.  The MASA service can choose to run in less secure modes
   by:

   1.  Not enforcing that a Voucher.  It nonce is posted to in the /requestauditlog URI instead.  The
   IDevIDAuthorityKeyIdentifier Voucher.  This results in
       distribution of Voucher that never expires and DevIDSerialNumber informs in effect makes
       the MASA
   server which log Domain an always trusted entity to the Pledge during any
       subsequent bootstrapping attempts.  That this occurred is requested so
       captured in the appropriate log can be prepared
   for information so that the response.  Using Domain registrar can
       make appropriate security decisions when a Pledge joins 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
       Domain.  This is useful to associate support use cases where Registrars
       might not be online during actual device deployment.  Because
       this request with the
   original, results in long lived Voucher and does not require the proof
       that the device is online this is only accepted when the
       Registrar is authenticated by now already validated, voucher request so as the MASA server and authorized to
   avoid an extra crypto validation.

   Request media type: application/voucherrequest+cms

7.6.
       provide this functionality.  The MASA authorization log Response

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

  {
    "version":"1",
    "events":[
      {
       "date":"<date/time RECOMMENDED to
       use this functionality only in concert with an enhanced level of
       ownership tracking (out-of-scope).  If the entry>",
       "domainID":"<domainID as extracted Pledge device is known
       to have a real-time-clock that is set from the domain CA certificate
                    within the CMS factory use of the audit a
       voucher request>",
       "nonce":"<any nonce if supplied (or the exact string 'NULL')>"
      },
      {
       "date":"<date/time of validity period is RECOMMENDED.

   2.  Not verifying ownership before responding with an Voucher.  This
       is expected to be a common operational model because doing so
       relieves the entry>",
       "domainID":"<domainID as extracted vendor providing MASA services from the domain CA certificate
                    within the CMS of having to track
       ownership during shipping and supply chain and allows for a very
       low overhead MASA service.  A Registrar uses the audit voucher request>",
       "nonce":"<any nonce if supplied (or the exact string 'NULL')>"
      }
    ]
  }

   Distribution of a large log is less than ideal.  This structure can
   be optimized
       information as follows: All nonce-less entries for the same domainID
   MAY be condensed into a defense in depth strategy to ensure that this
       does not occur unexpectedly (for example when purchasing new
       equipment the single most recent nonceless entry.

   A Registrar uses this log information to make would throw an informed decision
   regarding the continued bootstrapping of the Pledge.  For example error if
   the any audit log includes unexpected domainIDs this
       information is indicative of
   problematic imprints by the Pledge.  If reported).

5.  IANA Considerations

5.1.  PKIX Registry

   This document requests a number for id-mod-MASAURLExtn2016(TBD) from
   the log includes nonce-less
   entries this is indicative of pkix(7) id-mod(0) Registry.  [[EDNOTE: fix names]]

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

6.  Security Considerations

   There are uses cases where the indicated
   domain MASA could be unavailable or
   uncooperative to trigger a reset of the device Registrar.  They include planned and take over management of
   it.  Equipment that is purchased pre-owned can be expected unplanned
   network partitions, changes to have MASA policy, or other instances where
   MASA policy rejects a claim.  These introduce an
   extensive history.

   Log entries containing operational risk to
   the Domain's ID Registrar owner that MASA/vendor 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 compared against local
   history logs in search of discrepancies.

7.7.  EST Integration for PKI bootstrapping

   The prior sections describe EST extensions necessary to enable fully
   automated bootstrapping.  Although the Voucher request/response
   structure members IDevIDAuthorityKeyIdentifier mitigated by Registrars
   that request and DevIDSerialNumber maintain long term copies of "nonceless" Vouchers.
   In that way they are specific guaranteed to PKI be able to repeat bootstrapping these are the only PKI specific
   aspects
   for their devices.

   The issuance of the extensions and future work might replace them with
   non-PKI structures.

   The prior sections provide functionality for the Pledge to obtain nonceless vouchers themselves create a
   trust anchor representative of security
   concern.  If the Domain.  The following section
   describe using EST to obtain Registrar of a locally previous domain can intercept
   protocol communications then it can use a previously issued PKI certificate.  The
   Pledge SHOULD leverage the discovered Registrar to proceed with
   certificate enrollment and, if they do, MUST implement the EST
   options described in this section.  The Pledge MAY perform
   alternative enrollment methods including discovering an alternate EST
   server, or proceed nonceless
   voucher to use its X.509 IDevID credential indefinitely.

7.7.1.  EST Distribution establish management control of CA Certificates

   The Pledge MUST request a pledge device even after
   having sold it.  This risk is mitigated by recording the full EST Distribution issuance of CA Certificates
   message.  See RFC7030, section 4.1.

   This ensures
   such vouchers in the MASA audit log that is verified by the Pledge has
   subsequent Registrar.  This reduces the complete set resale value of current CA
   certificates beyond the domainCAcert (see Section 7.3 for equipment
   because future owners will detect the lowered security inherent in
   the existence of a
   discussion nonceless voucher that would be trusted by their
   Pledge.  This accurately reflects a balance between partition
   resistant recovery and security of future bootstrapping.  Registrars
   take the limitations).  Although these restrictions are
   acceptable for 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 integrated with initial bootstrapping they
   are not appropriate for ongoing PKIX end entity certificate
   validation.

7.7.2.  EST CSR Attributes

   Automated bootstrapping occurs is representative
   of a valid vendor customer, even without local administrative
   configuration validating ownership of the Pledge.  In some deployments its plausible that
   the
   specific Pledge generates devices, helps to mitigate this.  Inserting a certificate request containing only identity
   information known
   cryptographic proof-of-possession step to the Pledge (essentially the X.509 IDevID
   information) and ultimately receives protocol operations is
   a certificate containing domain
   specific identity information.  Conceptually possible area of future work.  One method that would not introduce
   additional round-trips would be for the CA has complete
   control over all fields issued in Registrar to share the end entity certificate.
   Realistically this is operationally difficult
   Pledge-Registrar TLS handshake with the current status
   of PKI certificate authority deployments where MASA service when requesting
   a voucher.  Doing so would allow the CSR is submitted MASA service to verify that the CA via a number of non-standard protocols.

   To alleviate operational difficulty
   Registrar's Server Certificate was signed by the Pledge MUST request Pledge's Certificate
   Verify message (which covers the EST
   "CSR Attributes" entire handshake).  [[EDNOTE:
   Security Considerations should not offer up new protocol ideas
   without a reason for having not done it...]]

   It is possible for an attacker to request a voucher from the EST server.  This allows MASA
   service directly after the local
   infrastructure to inform real Registrar obtains an audit log.  If
   the Pledge of attacker could also force the proper fields bootstrapping protocol to include
   in the generated CSR.

   [[EDNOTE: The following reset
   there is specific a theoretical opportunity for the attacker to anima purposes and should be
   moved use their
   voucher to an appropriate anima document so as take control of the Pledge but then proceed to keep bootstrapping as
   generic as possible: What we want are a 'domain name' stored in [TBD]
   and an 'ACP IPv6 address' stored in the iPAddress field as specified
   in RFC5208 s4.2.1.6. ref ACP draft where certificate verification
   [TBD].  These should go into the subjectaltname in enroll with
   the [TBD]
   fields.]].  If target domain.  Possible prevention mechanisms include:

   o  Per device rate limits on the hardwareModuleName in MASA service ensure such timing
      attacks are difficult.

   o  The Registrar can repeat the X.509 IDevID request for audit log information at
      some time after bootstrapping is
   populated then it SHOULD by default be propagated complete.

   To facilitate logging and administrative oversight the Pledge reports
   on Voucher parsing status to the LDevID along
   with Registrar.  In the hwSerialNum.  The registar SHOULD support local policy
   concerning this functionality.  [[EDNOTE: extensive use case of EST CSR
   Attributes might need an new OID definition]].]]

   The Registar MUST also confirm the resulting CSR a failure
   this information is formatted as
   indicated before forwarding the request informative to a CA.  If the potentially malicious Registar
   but this is
   communicating with RECOMMENDED anyway because of the CA using a protocol like full CMC which
   provides mechanisms to override operational benefits of
   an informed administrator in cases where the CSR attributes, then these
   mechanisms MAY be used even if failure is indicative of
   a problem.

   To facilitate truely limited clients EST RFC7030 section 3.3.2
   requirements that the client ignores CSR Attribute
   guidance.

7.7.3.  EST Client Certificate Request

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

7.7.4.  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 authentication
   model have been reduced in Section 4 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 statement that clients only
   "SHOULD" support either such a model.

   In  This reflects current (poor)
   practices that are NOT RECOMMENDED.

   During the case provisional period of a FAIL the Reason string indicates why the most recent
   enrollment failed.  The SubjectKeyIdentifier field connection all HTTP header and
   content data MUST treated as untrusted data.  HTTP libraries are
   regularly exposed to non-secured HTTP traffic: mature libraries
   should not have any problems.

   Pledge's 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 included
   if multple
   voucher's issued from the enrollment MASA if all registrars attempt was for a keypair that is locally known to claim the client.  If EST /serverkeygen was used and failed then the field
   device.  This is ommited from the status telemetry.

   In the case of not a SUCCESS failure and the Reason string is ommitted. Pledge choses whichever
   voucher to accept based on internal logic.  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"
    "SubjectKeyIdentifier":"<base64 encoded subjectkeyidentifier for the
                             enrollment that failed>"
  }

   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 Registrar's verifying
   log information will see multiple entries and take this message was
   recieved over an TLS session with a matching client certificate.
   This allows into account
   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.

7.7.5.  EST over CoAP

   [[EDNOTE: In order analytics purposes.

7.  Acknowledgements

   We would like to support smaller devices thank the above section on
   Proxy behavior introduces mandatory to implement support various reviewers for CoAP
   support by the Proxy.  This implies similar support by the Pledge their input, in
   particular Brian Carpenter, Toerless Eckert, Fuyu Eleven, Eliot Lear,
   Sergey Kasatkin, Markus Stenberg, and
   Registrar Peter van der Stok

8.  References

8.1.  Normative References

   [I-D.ietf-anima-autonomic-control-plane]
              Behringer, M., Eckert, T., and means that the EST protocol operation encapsulation
   into CoAP needs to be described.  EST is HTTP based S. Bjarnason, "An Autonomic
              Control Plane", draft-ietf-anima-autonomic-control-
              plane-06 (work in progress), March 2017.

   [I-D.ietf-anima-voucher]
              Watsen, K., Richardson, M., Pritikin, M., and "CoaP is
   designed to easily interface with HTTP T. Eckert,
              "Voucher Profile for integration" [RFC7252].
   Use of CoAP implies Datagram TLS (DTLS) wherever this document
   describes TLS handshake specifics.  A complexity is that the large
   message sizes necessary for bootstrapping will require support for
   [draft-ietf-core-block].]]

8.  Reduced security operational modes

   A common requirement of bootstrapping is to support less secure
   operational modes Bootstrapping Protocols", draft-ietf-
              anima-voucher-02 (work in progress), March 2017.

   [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 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.

8.1.  Trust Model

   +--------+         +---------+    +------------+     +------------+
   | New    |         | Circuit |    | Domain     |     | Vendor     |
   | Entity |         | Proxy   |    | Registrar  |     | Service    |
   |        |         |         |    |            |     | (Internet  |
   +--------+         +---------+    +------------+     +------------+

   Figure 10
   Pledge:  The Pledge could be compromised RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

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

   [RFC3748]  Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and all security decisions are made on the vendor
      service.

   Vendor Service, MASA:  This form H.
              Levkowetz, Ed., "Extensible Authentication Protocol
              (EAP)", RFC 3748, DOI 10.17487/RFC3748, June 2004,
              <http://www.rfc-editor.org/info/rfc3748>.

   [RFC3927]  Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
              Configuration of vendor service is trusted to
      accurately log all claim attempts IPv4 Link-Local Addresses", RFC 3927,
              DOI 10.17487/RFC3927, May 2005,
              <http://www.rfc-editor.org/info/rfc3927>.

   [RFC4862]  Thomson, S., Narten, T., 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 vendor.

   Vendor Service, Ownership Validation:  This form T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862,
              DOI 10.17487/RFC4862, September 2007,
              <http://www.rfc-editor.org/info/rfc4862>.

   [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,
              <http://www.rfc-editor.org/info/rfc5280>.

   [RFC5386]  Williams, N. and M. Richardson, "Better-Than-Nothing
              Security: An Unauthenticated Mode of vendor service is
      trusted to accurately know which device is owned by which domain.

8.2.  New Entity security reductions

   The Pledge MAY support "trust on first use" on physical interfaces
   but MUST NOT support "trust on first use" on network interfaces.
   This is because "trust on first use" permanently degrades the
   security for all other use cases.

   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 vendor
   service is unavailable.  This behavior SHOULD be available via IPsec", RFC 5386,
              DOI 10.17487/RFC5386, November 2008,
              <http://www.rfc-editor.org/info/rfc5386>.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, DOI 10.17487/RFC5652, September 2009,
              <http://www.rfc-editor.org/info/rfc5652>.

   [RFC5660]  Williams, N., "IPsec Channels: Connection Latching",
              RFC 5660, DOI 10.17487/RFC5660, October 2009,
              <http://www.rfc-editor.org/info/rfc5660>.

   [RFC6762]  Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
              DOI 10.17487/RFC6762, February 2013,
              <http://www.rfc-editor.org/info/rfc6762>.

   [RFC6763]  Cheshire, S. and M. Krochmal, "DNS-Based Service
              Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
              <http://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,
              <http://www.rfc-editor.org/info/rfc7030>.

   [RFC7228]  Bormann, C., Ersue, M., and A. Keranen, "Terminology for
              Constrained-Node Networks", RFC 7228,
              DOI 10.17487/RFC7228, May 2014,
              <http://www.rfc-editor.org/info/rfc7228>.

8.2.  Informative References

   [I-D.behringer-homenet-trust-bootstrap]
              Behringer, M., Pritikin, M., and S. Bjarnason,
              "Bootstrapping Trust on a Homenet", draft-behringer-
              homenet-trust-bootstrap-02 (work in progress), February
              2014.

   [I-D.ietf-anima-grasp]
              Bormann, C., Carpenter, B., and B. Liu, "A Generic
              Autonomic Signaling Protocol (GRASP)", draft-ietf-anima-
              grasp-12 (work in progress), May 2017.

   [I-D.ietf-netconf-zerotouch]
              Watsen, K. and M. Abrahamsson, "Zero Touch Provisioning
              for NETCONF or RESTCONF based Management", draft-ietf-
              netconf-zerotouch-13 (work in progress), March 2017.

   [I-D.lear-mud-framework]
              Lear, E., "Manufacturer Usage Description Framework",
              draft-lear-mud-framework-00 (work in progress), January
              2016.

   [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-01 (work in progress), July 2016.

   [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, <http://www.rfc-editor.org/info/rfc2473>.

   [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,
              <http://www.rfc-editor.org/info/rfc7217>.

   [RFC7435]  Dukhovni, V., "Opportunistic Security: Some Protection
              Most of the Time", RFC 7435, DOI 10.17487/RFC7435,
              December 2014, <http://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,
              <http://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>.

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 Local-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.

   Performs DNS-based Service Discovery [RFC6763] over normal DNS
   operations.  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.

   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 vendor provided
   bootstrapping server by performing a DNS lookup using a well known
   URI such as "bootstrapks.vendor-example.com".  The details of the URI
   are vendor specific.  Vendors that leverage this method on the Pledge
   are responsible for providing the bootstrapks service.

   The current DNS services returned during each query is 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 [FIND-good-REF].

   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
   require 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 represending 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 seperate 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 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 it's 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
   it's 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 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 it's link-local address.  The
   Join Proxy must also advertise this address as the address to which
   to connect to when advertising it's 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.

   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 need be implemented may
   find need for a virtual interface per Join Proxy to be problematic.
   There are other mechanism which can make be done.

   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 send.

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

Appendix D.  To be deprecated: Consolidation remnants

   [[EDNOTE: As per working group feedback there were multiple instances
   where this document repeated itself.  To address this we have moved
   all text to this appendix and restored only one copy of each
   normative discussion.  The next pass will reduce and delete this
   appendix to '0'; although some may be maintained in a design
   considerations appendix.]]

D.1.  Functional Overview

   Entities behave in an autonomic fashion.  They discover each other
   and autonomically bootstrap into a key infrastructure delineating the
   autonomic domain.  See [RFC7575] for more information.

   This section details the state machine and operational flow for each
   of the main three entities.  The pledge, the domain (primarily a
   Registrar) and the MASA service.

   A representative flow is shown in Figure 2:

   +--------+         +---------+    +------------+     +------------+
   | Pledge |         | Circuit |    | Domain     |     | Vendor     |
   |        |         | Proxy   |    | Registrar  |     | Service    |
   |        |         |         |    |            |     | (Internet  |
   +--------+         +---------+    +------------+     +------------+
     |                     |                   |                    |
     |<-RFC3927 IPv4 adr   | Appendix A        |                    |
   or|<-RFC4862 IPv6 adr   |                   |                    |
     |                     |                   |                    |
     |-------------------->|                   |                    |
     | optional: mDNS query| Appendix B        |                    |
     | RFC6763/RFC6762     |                   |                    |
     |                     |                   |                    |
     |<--------------------|                   |                    |
     | 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---Request Voucher (include nonce)------>|                    |
     P                     |                   |                    |
     P                     |       /--->       |                    |
     P                     |       |      [accept device?]          |
     P                     |       |      [contact Vendor]          |
     P                     |       |           |--Pledge ID-------->|
     P                     |       |           |--Domain ID-------->|
     P                     |       |           |--optional:nonce--->|
     P                     |       |           |     [extract DomainID]
     P                     |       |           |                    |
     P                     |    optional:      |     [update audit log]
     P                     |       |can        |                    |
     P                     |       |occur      |                    |
     P                     |       |in         |                    |
     P                     |       |advance    |                    |
     P                     |       |           |                    |
     P                     |       |           |<-device audit log--|
     P                     |       |           |<- voucher ---------|
     P                     |       \---->      |                    |
     P                     |                   |                    |
     P                     |       [verify audit log and voucher]   |
     P                     |                   |                    |
     P<------voucher---------------------------|                    |
   [verify voucher ]       |                   |                    |
   [verify provisional cert|                   |                    |
     |                     |                   |                    |
     |<--------------------------------------->|                    |
     | Continue with RFC7030 enrollment        |                    |
     | using now bidirectionally authenticated |                    |
     | TLS session.        |                   |                    |
     |                     |                   |                    |
     |                     |                   |                    |
     |                     |                   |                    |

   Figure 2

   [[UNRESOLVED:need to restore some functional overview section for all
   these diagrams]]In order to obtain a Voucher and associated logs a
   Registrar contacts the MASA service Service using REST calls:

              +-----------+ +----------+ +-----------+ +----------+
              | New       | | Circuit  | |           | |          |
              | Entity    | | Proxy    | | Registrar | | Vendor   |
              |           | |          | |           | |          |
              ++----------+ +--+-------+ +-----+-----+ +--------+-+
               |               |               |                |
               |               |               |                |
               |   TLS hello   |  TLS hello    |                |
   Establish   +---------------C--------------->                |
   TLS         |               |               |                |
   connection  |               | Server Cert   |                |
               <---------------C---------------+                |
               | Client Cert   |               |                |
               +---------------C--------------->                |
               |               |               |                |
   HTTP REST   | POST /requestvoucher          |                |
   Data        +--------------------nonce------>                |
               |               .               | /requestvoucher|
               |               .               +---------------->
               |                               <----------------+
               |                               | /requestlog    |
               |                               +---------------->
               |            voucher            <----------------+
               <-------------------------------+                |
               | (optional config information) |                |
               |               .               |                |
               |               .               |                |

   Figure 8

   In some use cases the Registrar may need to contact the Vendor in
   advanced, for example when the target network is air-gapped.  The
   nonceless request format is provided for this and the resulting flow
   is slightly different.  The security differences associated with not
   knowing the nonce are discussed below:

              +-----------+ +----------+ +-----------+ +----------+
              | New       | | Circuit  | |           | |          |
              | Entity    | | Proxy    | | Registrar | | Vendor   |
              |           | |          | |           | |          |
              ++----------+ +--+-------+ +-----+-----+ +--------+-+
               |               |               |                |
               |               |               |                |
               |               |               | /requestvoucher|
               |               |  (nonce       +---------------->
               |               |  unknown)     <----------------+
               |               |               | /requestlog    |
               |               |               +---------------->
               |               |               <----------------+
               |   TLS hello   |  TLS hello    |                |
   Establish   +---------------C--------------->                |
   TLS         |               |               |                |
   connection  |               | Server Cert   |                |
               <---------------C---------------+                |
               | Client Cert   |               |                |
               |               |               |                |
   HTTP REST   | POST /requestvoucher          |                |
   Data        +----------------------nonce---->   (discard     |
               |            voucher            |   nonce)       |
               <-------------------------------+                |
               | (optional config information) |                |
               |               .               |                |
               |               .               |                |

   Figure 9

D.1.1.  Behavior of a Pledge

   A pledge that has not yet been bootstrapped attempts to find a local
   configuration
   domain and join it.  A pledge [[RESOLVED:MUST NOT]] automatically
   initiate bootstrapping if it has already been configured or is in the
   process of being configured.

   States of a pledge are as follows:

                +--------------+
                |   Start      |
                |              |
                +------+-------+
                       |
                +------v-------+
                |  Discover    |
   +------------>              |
   |            +------+-------+
   |                   |
   |            +------v-------+
   |            |  Identity    |
   ^------------+              |
   | rejected   +------+-------+
   |                   |
   |            +------v-------+
   |            | Request      |
   |            | Join         |
   |            +------+-------+
   |                   |
   |            +------v-------+
   |            |  Imprint     |   Optional
   ^------------+              <--+Manual input (Appendix C)
   | Bad Vendor +------+-------+
   | response          |
   |            +------v-------+
   |            |  Enroll      |
   ^------------+              |
   | Enroll     +------+-------+
   | Failure           |
   |            +------v-------+
   |            |  Being       |
   ^------------+  Managed     |
    Factory     +--------------+
    reset

   Figure 3

   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.  Requests to Join the discovered Registrar.  A unique nonce
       [[RESOLVED: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
       vendor 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.

   The following sections describe each of these steps in more detail.

D.1.1.1.  Discovery

   [[RESOLVED:TEXT moved up into above]]

D.1.1.2.  Identity

   The Pledge identifies itself during the communication protocol
   handshake.  If the client identity is rejected (that is, the TLS
   handshake does not complete) the Pledge repeats the Identity process
   using the next proxy or discovery method available.

   [[RESOLVED: need normative statement in protocol section]] The
   bootstrapping protocol server is not initially authenticated.  Thus
   the connection is provisional and all data received is untrusted
   until sufficiently validated even though it is over a TLS connection.
   This is aligned with the existing provisional mode of EST [RFC7030]
   during s4.1.1 "Bootstrap Distribution of CA Certificates".  See
   Section 3.4 for more information about when the TLS connection
   authentication is completed.

   [[RESOLVED:]]All security associations established are between the
   new device and the Bootstrapping server regardless of proxy
   operations.

D.1.1.2.1.  Concurrent attempts to join

   [[RESOLVED: by dropping this text. the "priority mechanism" is
   unspecified thus any discussion is unclear.  Not only that once an
   initial request is sent to the registrar the question of multiple
   MASA interactions has already occurred.  Nothing breaks if
   implementations do this.  I've added text to the security
   considerations indicating the end result (MASA entries that might be
   ignored by the device but which confuse the end administrator)]] The
   Pledge MAY attempt multiple mechanisms concurrently, but if it does
   so, it MUST wait in the provisional state until all mechanisms have
   either succeeded or physical presence failed, and then MUST proceed with the highest
   priority mechanism which has succeed.  To proceed beyond this point,
   specifically, to provide a nonce, could result in the MASA
   gratuitously auditing a connection.

D.1.1.3.  Request Join

   The Pledge POSTs a request to join the domain to the Bootstrapping
   server.  This request contains a Pledge generated nonce and informs
   the Bootstrapping server which imprint methods the Pledge will
   accept.

   The nonce ensures the Pledge can verify that responses are specific
   to ensure new entities this bootstrapping attempt.  This minimizes the use of global time
   and provides a substantial benefit for devices without a valid clock.

D.1.1.3.1.  Redirects during the Join Process

   [[RESOVED via current root protocol discussion. reference to
   mdnsmethods is dropped]] EST [RFC7030] describes situations where the
   bootstrapping server MAY redirect the client to an alternate server
   via a 3xx status code.  Such redirects MAY be accepted if the pledge
   has used the methods described in Appendix B, in combination with an
   implicit trust anchor.  Redirects during the provisional period are
   otherwise unstrusted, and MUST cause a failure.

D.1.1.4.  Imprint

   The Pledge validates the voucher and accepts the Registrar ID.  The
   provisional TLS connection is validated using the Registrar ID from
   the voucher.

D.1.1.5.  Lack of realtime clock APPENDIX

   [[RESOVED: entire section promoted back into the main text]]
   Many devices when bootstrapping do not have knowledge of the current
   time.  Mechanisms like Network Time Protocols can
   always not be deployed even when autonomic methods fail.  This allows for
   unsecured imprint.

   It secured
   until bootstrapping is RECOMMENDED that this only be available if hardware assisted
   NEA [RFC5209] complete.  Therefore bootstrapping is supported.

8.3.  Registrar security reductions

   A Registrar can choose to accept devices using less secure methods.
   These methods defined
   in a method that does not require knowledge of the current time.

   Unfortunately there are acceptable moments during bootstrapping when low security models
   certificates are needed, verified, such as during the security decisions TLS handshake, where
   validity periods are being made confirmed.  This paradoxical "catch-22" is
   resolved by the local administrator, but
   they MUST NOT be Pledge maintaining a concept of the default behavior:

   1.  A registrar MAY choose to accept all devices, or all devices 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 a
       particular type, at realtime clock can
      be used by the administrator's discretion. Registrar.  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 bullet expands on a unique
       identity without closely
      related issue regarding Pledge lifetimes.  RFC5280 indicates that
      long lived Pledge certifiates "SHOULD be assigned the
      GeneralizedTime value of 99991231235959Z" [RFC7030] so the benefit of authenticating that claimed
       identity.  This could occur when
      Registrar MUST support such lifetimes and SHOULD support ignoring
      Pledge lifetimes if they did not follow the RFC5280
      recommendations.

   o  The Pledge authenticates the voucher presented to it.  During this
      authentication the Pledge ignores certificate lifetimes (by
      necessity because it does not include an
       X.509 IDevID factory installed credential.  New Entities without
       an X.509 IDevID credential MAY form have a clock).  The voucher itself
      SHOULD contain the Section 7.1 nonce included in the original request using which
      proves the Section 7.2 format to ensure voucher is fresh.

   o  Once the Pledge's serial number
       information voucher is provided to accepted the Registar (this includes validity period of the
       IDevIDAuthorityKeyIdentifier value which would be statically
       configured on
      domainCAcert in the Pledge).  The Pledge MAY refused to provide voucher (see Section 3.4) now serves as a
       TLS client
      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 (as one is not available). assumed to be valid by the Pledge.
      The Pledge
       SHOULD support HTTP-based or certificate-less TLS authentication is now willing to use this credential for client
      authentication.

D.1.1.6.  Enrollment

   As the final step of bootstrapping a Registrar helps to issue a
   domain specific credential to the Pledge.  For simplicity in this
   document, a Registrar primarily facilitates issuing a credential by
   acting as an RFC5280 Registration Authority for the Domain
   Certification Authority.

   Enrollment proceeds as described in [RFC7030].  Authentication of the
   EST RFC7030 section 3.3.2.  A Registrar MUST NOT
       accept unauthenticated New Entities unless it has been configured server is done using the Voucher rather than the methods defined
   in EST.

   [[RESOLVED: moved 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 request nonce-less Vouchers from protocol discussion]]Once the MASA service
       (by not including a nonce Voucher is
   received, as specified in this document, the request).  These Vouchers can
       then be transmitted client has sufficient
   information to leverage the existing communication channel with a
   Registrar and stored until they are
       needed during to continue an EST RFC7030 enrollment.  Enrollment picks up
   at RFC7030 section 4.1.1.  bootstrapping operations.  This is for use cases where target network is protected by an air gap and therefore the Voucher provides
   the "out-of-band" CA certificate fingerprint (in this case the full
   CA certificate) such that the client can
       not contact now complete the MASA service during Pledge deployment.

   4.  A registrar MAY ignore unrecognized nonce-less log entries.  This
       could occur when used equipment is purchased TLS server
   authentication.  At this point the client continues with a valid history
       being deployed in air gap networks that required permanent
       Vouchers.

8.4.  MASA security reductions

   Lower security modes chosen by EST
   enrollment operations including "CA Certificates Request", "CSR
   Attributes" and "Client Certificate Request" or "Server-Side Key
   Generation".

   [[RESOLVED: included into EST discussion]]For the MASA service effect all device
   deployments unless bound to purposes of
   creating 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 ANIMA Autonomic Control Plane, the Voucher.  This results in
       distribution contents of Voucher that never expires and in effect makes the Domain an always trusted entity to new
   certificate MUST be carefully specified.
   [I-D.ietf-anima-autonomic-control-plane] section 5.1.1 contains
   details.  The Registrar MUST provide the Pledge during any
       subsequent bootstrapping attempts.  That this occurred is
       captured in the log correct ACP information so that
   to populate the Domain registrar can
       make appropriate security decisions when a Pledge joins subjectAltName / rfc822Name field in the
       Domain.  This is useful "CSR
   Attributes" step.

D.1.1.7.  Being Managed

   [[RESOLVED: by slight change to support use cases where Registrars
       might not be online during actual device deployment.  Because introduction text.]] Functionality to
   provide generic "configuration" information is supported.  The
   parsing of this results in long lived Voucher data and does not require the proof
       that any subsequent use of the device data, for example
   communications with a Network Management System is online this out of scope but
   is only accepted when the
       Registrar expected to occur after bootstrapping enrollment is authenticated by complete.
   This ensures that all communications with management systems which
   can divulge local security information (e.g. network topology or raw
   key material) is secured using the MASA server and authorized to
       provide this functionality. local credentials issued during
   enrollment.

   The MASA server is RECOMMENDED Pledge uses bootstrapping to
       use this functionality join only in concert with an enhanced level one domain.  Management by
   multiple domains is out-of-scope of
       ownership tracking (out-of-scope).  If bootstrapping.  After the Pledge device is known
       to have
   has successfully joined a real-time-clock that domain and is set from being managed it is plausible
   that the factory use domain can insert credentials for other domains depending on
   the device capabilities.

   See Appendix D.1.5.

D.1.2.  Behavior of a
       voucher validity period is RECOMMENDED.

   2.  Not verifying ownership before responding with an Voucher.  This Join Proxy

   The role of the Proxy is expected to be a common operational model because doing so
       relieves facilitate communications.  The Proxy
   forwards packets between the vendor providing MASA services from having to
       tracking ownership during shipping and supply chain Pledge and allows
       for a very low overhead MASA service.  A Registrar uses that has been
   configured on the audit
       log information as a defense in depth strategy Proxy.

   [[UNRESOLVED: since proxy behavior is not visible we can limit
   ourselves to ensure that
       this discussion of what the protocol does to enable/faciliate
   a theoretical proxy]]The Proxy does not occur unexpectedly (for example when purchasing new
       equipment terminate the Registrar would throw TLS handshake.

   [[UNRESOLVED: this is an error anima architecture requirement to use BRSKI?
   move to there?]] A Proxy is always assumed even if any audit log
       information it is reported).

9.  Security Considerations

   There are uses cases where the MASA could be unavailable or
   uncooperative to the directly
   integrated into a Registrar.  They include planned and unplanned
   network partitions, changes to MASA policy, or other instances where
   MASA policy rejects  (In a claim.  These introduce an operational risk to completely autonomic network, the
   Registrar owner MUST provide proxy functionality so that MASA/vendor behavior might limit the ability
   to re-boostrap a Pledge device.  For example this might be an issue
   during disaster recovery.  This risk it can be mitigated by Registrars
   that request
   discovered, and maintain long term copies the network can grow concentrically around the
   Registrar)

   As a result of "nonceless" Vouchers.
   In that way they are guaranteed the Proxy Discovery process in section
   Appendix D.1.1.1, the port number exposed by the proxy does not need
   to be able to repeat bootstrapping
   for their devices.

   The issuance of nonceless vouchers themselves create a security
   concern. well known, or require an IANA allocation.

   If the Registrar of a previous domain can intercept
   protocol communications then Proxy joins an Autonomic Control Plane
   ([I-D.ietf-anima-autonomic-control-plane]) it can SHOULD use a previously issued nonceless
   voucher Autonomic
   Control Plane secured GRASP ([I-D.ietf-anima-grasp]) to establish management control of a pledge device even after
   having sold it.  This risk is mitigated by recording discovery the issuance
   Registrar address and port.  As part of
   such vouchers in the MASA audit log that is verified by discovery process, the
   subsequent Registrar.  This reduces
   proxy mechanism (Circuit Proxy vs IPIP encapsulation) is agreed to
   between the resale value of Registrar and Join Proxy.

   For the equipment
   because future owners will detect IPIP encapsulation methods, the lowered security inherent in port announced by the existence of a nonceless voucher that would Proxy
   MUST be trusted by their
   Pledge.  This accurately reflects a balance between partition
   resistant recovery and security of future bootstrapping.  Registrars
   take the Pledge's audit history into account when applying policy same as on the registrar in order for the proxy to
   new devices.

   The MASA server is exposed remain
   stateless.

   In order to DoS attacks wherein attackers claim an
   unbounded number of devices.  Ensuring a Registrar is representative permit the proxy functionality to be implemented on the
   maximum variety of a valid vendor customer, even without validating ownership devices the chosen mechanism SHOULD use the
   minimum amount of
   specific Pledge devices, helps state on the proxy device.  While many devices in
   the ANIMA target space will be rather large routers, the proxy
   function is likely to mitigate this.  Inserting be implemented in the control plane CPU of such
   a
   cryptographic proof-of-possession step to device, with available capabilities for the protocol operations is proxy function similar
   to many class 2 IoT devices.

   The document [I-D.richardson-anima-state-for-joinrouter] provides a possible area
   more extensive analysis of future work.  One method that would not introduce
   additional round-trips would be for the alternative proxy methods.

D.1.2.1.  CoAP connection to Registrar

   [[RESOLVED:this section thus removed]]The CoAP mechanism was
   depreciated.

D.1.2.2.  HTTPS proxy connection to share the Plege- Registrar TLS handshake with

   The proxy SHOULD also provide one of: an IPIP encapsulation of HTTP
   traffic on TCP port TBD to the MASA service when requesting registrar, or a
   voucher.  Doing so would allow TCP circuit proxy that
   connects the MASA service Pledge to verify that a Registrar.

   When the
   Registrar's Server Certificate was signed by Proxy provides a circuit proxy to a Registrar the Pledge's Certificate
   Verify message (which covers Registrar
   MUST accept HTTPS connections.

   When the entire handshake).

   It is possible for an attacker Proxy provides a stateless IPIP encapsulation to request a voucher from the MASA
   service directly after
   Registrar, then the real Registrar obtains an audit log.  If
   the attacker could also force will have to perform IPIP
   decapsulation, remembering the bootstrapping protocol originating outer IPIP source address
   in order to reset
   there qualify the inner link-local address.  This is a kind of
   encapsulation and processing which is similar in many ways to how
   mobile IP works.

   Being able to connect a TCP (HTTP) or UDP (CoAP) socket to a link-
   local address with an encapsulated IPIP header requires API
   extensions beyond [RFC3542] for UDP use, and requires a theoretical opportunity for the attacker to use their
   voucher to take control form of
   connection latching (see section 4.1 of [RFC5386] and all of
   [RFC5660], except that a simple IPIP tunnel is used rather than an
   IPsec tunnel).

D.1.3.  Behavior of the Pledge but then proceed to enroll with Registrar

   A Registrar listens for Pledges and determines if they can join the target
   domain.  Possible prevention mechanisms include:

   o  Per device rate limits on  A Registrar obtains a Voucher from the MASA service ensure such timing
      attacks are difficult.

   o  The Registrar can repeat the request for audit log information at
      some time after bootstrapping is complete.

   To facilitate logging and administrative oversight the Pledge reports
   on Voucher parsing status
   delivers them to the Registrar.  In Pledge as well as facilitating enrollment with
   the case of a failure
   this information is informative domain PKI.

   [[RESOLVED: moved to a potentially malicious Registar
   but this discovery discussion]] A Registrar is RECOMMENDED anyway because of typically
   configured manually.  When the operational benefits of Registrar joins an informed administrator in cases where the failure Autonomic Control
   Plane ([I-D.ietf-anima-autonomic-control-plane]) it MUST respond to
   GRASP ([I-D.ietf-anima-grasp]) M_DISCOVERY message.  See
   Section 3.1.2

   Registrar behavior is indicative of
   a problem.

   To facilitate truely limited clients EST RFC7030 section 3.3.2
   requirements that as follows:

   Contacted by Pledge
           +
           |
   +-------v----------+
   | Entity           | fail?
   | Authentication   +---------+
   +-------+----------+         |
           |                    |
   +-------v----------+         |
   | Entity           | fail?   |
   | Authorization    +--------->
   +-------+----------+         |
           |                    |
   +-------v----------+         |
   | Claiming the     | fail?   |
   | Entity           +--------->
   +-------+----------+         |
           |                    |
   +-------v----------+         |
   | Log Verification | fail?   |
   |                  +--------->
   +-------+----------+         |
           |                    |
   +-------v----------+    +----v-------+
   | Forward          |    |            |
   | Voucher          |    | Reject     |
   | to the client MUST support a client Pledge    |    | Device     |
   |                  |    |            |
   +------------------+    +------------+

   Figure 4

D.1.3.1.  Pledge Authentication

   The applicable authentication
   model have been reduced methods detailed in Section 8 to a statement that clients only
   "SHOULD" support such a model.  This reflects current (poor)
   practices that are NOT RECOMMENDED.

   During the provisional period EST [RFC7030] are:

   o  [[RESOLVED:pointed out in protocol details]]the use of an X.509
      IDevID credential during the connection all HTTP header and
   content data MUST treated as untrusted data.  HTTP libraries are
   regularly exposed to non-secured HTTP traffic.

10.  Acknowledgements

   We would like to thank TLS client authentication,

   o  or the various reviewers for their input, in
   particular Brian Carpenter, Toerless Eckert, Fuyu Eleven, Eliot Lear,
   Sergey Kasatkin, Markus Stenberg, and Peter van der Stok

11.  References

11.1.  Normative References

   [I-D.ietf-anima-autonomic-control-plane]
              Behringer, M., Eckert, T., and S. Bjarnason, "An Autonomic
              Control Plane", draft-ietf-anima-autonomic-control-
              plane-05 (work in progress), January 2017.

   [I-D.ietf-anima-voucher]
              Watsen, K., Richardson, M., Pritikin, M., and T. Eckert,
              "Voucher and Voucher Revocation Profiles for Bootstrapping
              Protocols", draft-ietf-anima-voucher-00 (work in
              progress), January 2017.

   [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,
              <http://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,
              <http://www.rfc-editor.org/info/rfc3542>.

   [RFC3927]  Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
              Configuration of IPv4 Link-Local Addresses", RFC 3927,
              DOI 10.17487/RFC3927, May 2005,
              <http://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,
              <http://www.rfc-editor.org/info/rfc4862>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., a secret that is transmitted out of band between the
      Pledge and W. Polk, "Internet a Registrar (this use case is not autonomic).

   In order to validate the X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <http://www.rfc-editor.org/info/rfc5280>.

   [RFC5386]  Williams, N. and M. Richardson, "Better-Than-Nothing
              Security: An Unauthenticated Mode IDevID credential a Registrar
   maintains a database of IPsec", RFC 5386,
              DOI 10.17487/RFC5386, November 2008,
              <http://www.rfc-editor.org/info/rfc5386>.

   [RFC5652]  Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
              RFC 5652, DOI 10.17487/RFC5652, September 2009,
              <http://www.rfc-editor.org/info/rfc5652>.

   [RFC5660]  Williams, N., "IPsec Channels: Connection Latching",
              RFC 5660, DOI 10.17487/RFC5660, October 2009,
              <http://www.rfc-editor.org/info/rfc5660>.

   [RFC6762]  Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
              DOI 10.17487/RFC6762, February 2013,
              <http://www.rfc-editor.org/info/rfc6762>.

   [RFC6763]  Cheshire, S. vendor trust anchors (e.g. vendor root
   certificates or keyIdentifiers for vendor root public keys).  For
   user interface purposes this database can be mapped to colloquial
   vendor names.  Registrars can be shipped with the trust anchors of a
   significant number of third-party vendors within the target market.

D.1.3.2.  Pledge Authorization

   [[UNRESOLVED: this is referenced above as how the MASA does
   authorization.  That is incorrect]]

   In a fully automated network all devices must be securely identified
   and M. Krochmal, "DNS-Based authorized to join the domain.

   A Registrar accepts or declines a request to join the domain, based
   on the authenticated identity presented.  Automated acceptance
   criteria include:

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

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

   o  allow a specific device from a vendor (as determined by the X.509
      IDevID) against a domain white list.  (The mechanism for checking
      a shared white list potentially used by multiple Registrars is out
      of scope).

   [[RESOLVED: this looks like good text to include in above]]To look
   the Pledge up in a domain white list a consistent method for
   extracting device identity from the X.509 certificate is required.
   RFC6125 describes Domain-Based Application Service
              Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
              <http://www.rfc-editor.org/info/rfc6763>.

   [RFC7030]  Pritikin, M., Ed., Yee, P., Ed., identity but here
   we require Vendor Device-Based identity.  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 D. Harkins, Ed.,
              "Enrollment over Secure Transport", RFC 7030,
              DOI 10.17487/RFC7030, October 2013,
              <http://www.rfc-editor.org/info/rfc7030>.

   [RFC7228]  Bormann, C., Ersue, M., therefore that can also be used for matching
   purposes.  The SERIALNUM-ID whitelist is collated according to vendor
   trust anchor since serial numbers are not globally unique.

   [[RESOLVED: into log request]]The Registrar MUST use the vendor
   provided MASA service to verify that the device's history log does
   not include unexpected Registrars.  If a device had previously
   registered with another domain, a Registrar of that domain would show
   in the log.

   [[RESOLVED: est integration section used 'SHOULD']]The authorization
   performed during BRSKI MAY be used for EST enrollment requests by
   proceeding with EST enrollment using the authenticated and A. Keranen, "Terminology for
              Constrained-Node Networks", RFC 7228,
              DOI 10.17487/RFC7228, May 2014,
              <http://www.rfc-editor.org/info/rfc7228>.

11.2.  Informative References

   [I-D.behringer-homenet-trust-bootstrap]
              Behringer, M., Pritikin, M., authorized
   TLS connection.  This minimizes the number of cryptographic and S. Bjarnason,
              "Bootstrapping Trust on
   protocol operations necessary to complete bootstrapping of the local
   key infrastructure.

D.1.3.3.  Claiming the New Entity

   Claiming an entity establishes an audit log at the MASA server and
   provides a Homenet", draft-behringer-
              homenet-trust-bootstrap-02 (work Registrar with proof, in progress), February
              2014.

   [I-D.ietf-anima-grasp]
              Bormann, C., Carpenter, B., the form of the Voucher, that the
   log entry has been inserted.  As indicated in Appendix D.1.1.4 a
   Pledge will only proceed with bootstrapping if a Voucher has been
   received.  The Pledge therefore enforces that bootstrapping only
   occurs if the claim has been logged.  There is no requirement for the
   vendor to definitively know that the device is owned by the
   Registrar.

   The Registrar obtains the MASA URI via static configuration or by
   extracting it from the X.509 IDevID credential.  See Section 2.2.

   During initial bootstrapping the Pledge provides a nonce specific to
   the particular bootstrapping attempt.  [[RESOLVED: to resolve this I
   updated many points where vouchers are referenced]]The Registrar
   SHOULD include this nonce when claiming the Pledge from the MASA
   service.  Claims from an unauthenticated Registrar are only serviced
   by the MASA resource if a nonce is provided.

   The Registrar can claim a Pledge that is not online by forming the
   request using the entities unique identifier and B. Liu, "A Generic
              Autonomic Signaling Protocol (GRASP)", draft-ietf-anima-
              grasp-09 (work not including a
   nonce in the claim request.  Vouchers obtained in progress), December 2016.

   [I-D.ietf-netconf-zerotouch]
              Watsen, K. this way do not
   have a lifetime and M. Abrahamsson, "Zero Touch Provisioning they provide a permanent method for NETCONF or RESTCONF based Management", draft-ietf-
              netconf-zerotouch-12 (work in progress), January 2017.

   [I-D.lear-mud-framework]
              Lear, E., "Manufacturer Usage Description Framework",
              draft-lear-mud-framework-00 (work the domain to
   claim the device.  Evidence of such a claim is provided in progress), January
              2016.

   [I-D.richardson-anima-state-for-joinrouter]
              Richardson, M., "Considerations the audit
   log entries available to any future Registrar.  Such claims reduce
   the ability for stateful vs stateless
              join router in ANIMA bootstrap", draft-richardson-anima-
              state-for-joinrouter-01 (work in progress), July 2016.

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

   [RFC2473]  Conta, A. future domains to secure bootstrapping and S. Deering, "Generic Packet Tunneling in
              IPv6 Specification", RFC 2473, DOI 10.17487/RFC2473,
              December 1998, <http://www.rfc-editor.org/info/rfc2473>.

   [RFC7217]  Gont, F., "A Method for Generating Semantically Opaque
              Interface Identifiers therefore
   the Registrar MUST be authenticated by the MASA service although no
   requirement is implied that the MASA associates this authentication
   with IPv6 Stateless Address
              Autoconfiguration (SLAAC)", RFC 7217,
              DOI 10.17487/RFC7217, April 2014,
              <http://www.rfc-editor.org/info/rfc7217>.

   [RFC7435]  Dukhovni, V., "Opportunistic Security: Some Protection
              Most of ownership.

   An Ownership Voucher requires the Time", RFC 7435, DOI 10.17487/RFC7435,
              December 2014, <http://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,
              <http://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>.

Appendix A.  IPv4 operations

A.1.  IPv4 Link Local addresses

   Instead of vendor to definitively know that a
   device is owned by a specific domain.  The method used to "claim"
   this are out-of-scope.  A MASA ignores or reports failures when an IPv6 link-local address,
   attempt is made to claim a device that has a an IPv4 address may be
   generated using [RFC3927]  Dynamic Configuration of IPv4 Link-Local
   Addresses.

   In Ownership Voucher.

D.1.3.4.  Log Verification

   A Registrar requests the case log information for the Pledge from the MASA
   service.  The log is verified to confirm that an IPv4 Local-Local address the following is formed, then true
   to the
   bootstrap process would continue as satisfaction of a Registrar's configured policy:

   o  Any nonceless entries in the IPv6 case log are associated with domainIDs
      recognized by looking for a
   (circuit) proxy.

A.2.  Use the registrar.

   o  Any nonce'd entries are older than when the domain is known to
      have physical possession of DHCPv4

   The Plege MAY obtain an IP address via DHCP [RFC2131].  The DHCP
   provided parameters for the Domain Name System can Pledge or that the domainIDs are
      recognized by the registrar.

   If any of these criteria are unacceptable to a Registrar the entity
   is rejected.  [[RESOLVED: moved to main body]] A Registrar MAY be used
   configured to perform
   DNS operations ignore the history of the device but it is RECOMMENDED
   that this only be configured 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 hardware assisted NEA [RFC5209] is
   supported.

   [[RESOLVED: added to main text]]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 a technologies such as block-chain or hash
   trees or the service
   "_bootstrapks._tcp.local.".

   To prevent unaccceptable levels like.  Doing so is out of network traffic the congestion
   avoidance mechanisms specified in [RFC6762] section 7 MUST be
   followed.  The Pledge SHOULD listen scope of this document but
   are anticipated improvements for an unsolicited broadcast
   response as described in [RFC6762].  This allows devices future work.

D.1.4.  Behavior of the MASA Service

   [[UNRESOLVED: primary value of keeping this discussion is to avoid
   announcing their presence via mDNS broadcasts
   distinguish between registrar and instead silently
   join a network masa particularly wrt to the
   protocol functions provided. perhaps add statements in each protocol
   entry "provided by watching for periodic unsolicited broadcast
   responses.

   Performs DNS-based Service Discovery [RFC6763] over normal DNS
   operations. masa" etc?]]

   The Manufacturer Authorized Signing Authority service searched for is
   "_bootstrapks._tcp.example.com".  In this case directly
   provided by the domain
   "example.com" is discovered as described in [RFC6763] section 11.
   This method is only available if manufacturer, or can be provided by a third party the host has received
   manufacturer authorizes.  It is a useable IPv4
   address via DHCPv4 as suggested in Appendix A.

   If no local bootstrapks cloud resource.  The MASA service
   provides the following functionalities to Registrars:

   Issue Vouchers:  In response to Registrar requests the MASA service
      issues vouchers.  Depending on the MASA policy the Registrar claim
      of device ownership is located either accepted or verified using out-of-
      scope methods (that are expected to improve over time).

   Log Vouchers Issued:  When a voucher is issued the act of issuing it
      includes updating the certifiable logs.  Future work to enhance
      and distribute these logs is out-of-scope but expected over time.

   Provide Logs:  As a baseline implementation of the GRASP
   mechanisms, or certified logging
      mechanism the above mentioned DNS-based Service Discovery MASA is repsonsible for reporting logged
      information.  The current method involves trusting the MASA.
      Other logging methods where the Pledge MAY contact a well known vendor provided
   bootstrapping server by performing MASA is less trusted are expected
      to be developed over time.

D.1.5.  Leveraging the new key infrastructure / next steps

   As the devices have a DNS lookup using common trust anchor, device identity can be
   securely established, making it possible to automatically deploy
   services across the domain in a well known
   URI such as "bootstrapks.vendor-example.com".  The details secure manner.

   Examples of services:

   o  Device management.

   o  Routing authentication.

   o  Service discovery.

D.1.5.1.  Network boundaries

   When a device has joined the URI
   are vendor specific.  Vendors that leverage this method on domain, it can validate the Pledge
   are responsible for providing domain
   membership of other devices.  This makes it possible to create trust
   boundaries where domain members have higher level of trusted than
   external devices.  Using the bootstrapks service. autonomic User Interface, specific
   devices can be grouped into to sub domains and specific trust levels
   can be implemented between those.

D.1.6.  Interactions with Network Access Control

   [[RESOLVED: via paragraph in 'scope of solution' discussion.]]

   The current DNS services returned during each query is maintained
   until bootstrapping assumption is completed.  If bootstrapping fails and that Network Access Control (NAC) completes using
   the Pledge returns to 's X.509 IDevID credentials and results in the Discovery state it picks up where it left off device
   having sufficient connectivity to discovery and continues attempting bootstrapping.  For example if communicate with the
   proxy.  Any additional connectivity or quarantine behavior by the first
   Multicast DNS _bootstrapks._tcp.local response doesn't work then NAC
   infrastructure is out-of-scope.  After the
   second and third responses are tried.  If these fail devices has completed
   bootstrapping 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 to trigger NAC to re-authenticate the
   Join Proxy for each connection that
   device and provide updated network privileges is relayed.  The Circuit Proxy also out-of-scope.

   This achieves the goal of a bootstrap architecture that can integrate
   with NAC but does not require NAC within the network where it wasn't
   previously required.  Future optimizations can be considered achieved by
   integrating the bootstrapping protocol directly into an initial EAP
   exchange.

D.2.  Domain Operator Activities

   This section describes how an operator interacts with a kind of Algorithm Gateway [FIND-good-REF].

   An alternative to proxying at domain that
   supports the TCP layer bootstrapping as described in this document.

D.2.1.  Instantiating the Domain Certification Authority

   This is to selectively forward
   at a one time step by the IP layer. domain administrator.  This moves all per-connection is an "off
   the shelf" CA with the exception that it is designed to work as an
   integrated part of the Join
   Registrar.  The IPIP tunnel statelessly forwards packets. security solution.  This
   section provides some explanation of some of precludes the details use of the
   Registrar discovery procotol which are
   3rd party certification authority services that do 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 provide
   support for delegation of certificate issuance decisions to form a bidirectional mechanism.  An IPIP tunnel is
   setup as follows.  The outer addresses are an ACP address of the Join
   Proxy, and domain
   managed Registration Authority.

D.2.2.  Instantiating the ACP address of Registrar

   This is a one time step by the Join Registrar.  The inner
   addresses seen domain administrator.  One or more
   devices in the tunnel domain are the link-local addresses of the
   network configured take on which the join activity is occuring.

   One way a Registrar function.

   A device can be configured to look at act as a Registrar or a device can
   auto-select itself to take on this construct is function, using a detection
   mechanism to consider that resolve potential conflicts and setup communication with
   the Domain Certification Authority.  Automated Registrar selection is extending attaching an interface to the network on which
   outside scope for this document.

D.2.3.  Accepting New Entities

   For each Pledge 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 informed of the traffic is being proxied through unique identifier
   (e.g. serial number) along with the manufacturer's identifying
   information (e.g. manufacturer root certificate).  This can happen in
   different ways:

   1.  Default acceptance: In the simplest case, the new device asserts
       its unique identity to a
   tunnel, and Registrar.  The registrar accepts all
       devices without authorization checks.  This mode does not need any special routing.

   There are a number of considerations with this mechanism which
   require cause some minor amounts of complexity.  Note that due provide
       security against intruders and is not recommended.

   2.  Per device acceptance: The new device asserts its unique identity
       to a Registrar.  A non-technical human validates the
   tunnels, identity,
       for example by comparing the Registrar sees multiple connections to a fe80::/10
   network on not just physical interfaces, but on each of identity displayed by the virtual
   interfaces represending registrar
       (for example using a smartphone app) with the tunnels.

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

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

   Each smartphone app "accept this device", or by other forms
       of these interfaces on pairing.  See also [I-D.behringer-homenet-trust-bootstrap] for
       how the Join Proxy may be seperate L3 routing
   domains, and therefore will have approach could work in a unique set homenet.

   3.  Whitelist acceptance: In larger networks, neither 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 previous
       approaches is to allocate an
   additional ACP address; one address for each network on which join
   traffic acceptable.  Default acceptance is occuring.  The Join Proxy SHOULD do not secure, and
       a GRASP M_NEG_SYN for
   each interface 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 manual per device methods do a GRASP negotiation with not scale.  Here, the proxy
   for each Join Interface that it needs to relay traffic from.  This registrar is
   to permit Registrars to configure the appropriate virtual interfaces
   before join traffic arrives.

   A Registrar serving
       provided a large number priori with a list of interfaces may not wish to
   allocate resources identifiers of devices that
       belong to every interface at all times, but can instead
   dynamically allocate interfaces.  It the network.  This list can do this by monitoring IPIP
   traffic be extracted from an
       inventory database, or sales records.  If a device is detected
       that arrives is not on it's 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 list of
   it's TCP and UDP stack could note known devices, it can still be
       manually accepted using the IPIP traffic origination in per device acceptance methods.

   4.  Automated Whitelist: an automated process that builds the
   socket control block
       necessary whitelists and make information available to the TCP layer
   (for HTTPS connections), or to the inserts them into the application (for CoAP
   connections) via a proprietary extension to larger network
       domain infrastructure is plausible.  Once set up, no human
       intervention is required in this process.  Defining the socket API.

C.3.  Proxy Neighbor Discovery by Join Proxy

   The Join Proxy MUST answer neighbor discovery messages exact
       mechanisms for this is out of scope although the
   address given by the Registrar registrar
       authorization checks is identified as being it's link-local address.  The
   Join Proxy must also advertise the logical integration
       point of any future work in this address as area.

   None of these approaches require the address to which
   to connect network to have permanent
   Internet connectivity.  Even when advertising it's existence.

   This proxy neighbor discovery means that the pledge will create TCP
   and UDP connections Internet based MASA service is
   used, it is possible to pre-fetch the correct Registrar address.  This matters
   as the TCP and UDP pseudo-header checksum includes required information from the destination
   address, and
   MASA a priori, for example at time of purchase such that devices can
   enroll later.  This supports use cases where the proxy to remain completely stateless, it must
   not domain network may
   be necessary for the checksum to entirely isolated during device deployment.

   Additional policy can be updated.

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

   TCP connections on the registrar SHOULD properly capture the ifindex future authorization decisions.
   For example an expected deployment time window or that a certain
   Proxy must be used.

D.2.4.  Automatic Enrollment of the incoming connection into the socket structure.  This is normal
   IPv6 socket API processing. Devices

   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 approach outlined in this
   information is available using the IP_PKTINFO auxiliary extension
   which is document provides a standard part secure zero-touch
   method to enroll new devices without any pre-staged configuration.
   New devices communicate with already enrolled devices of the IPv6 sockets API.

   A registrar application could, after receipt domain,
   which proxy between the new device and a Registrar.  As a result of an initial CoAP
   message from the Pledge, create
   this completely automatic operation, all devices obtain a connected UDP socket (including the
   ifindex information). domain
   based certificate.

D.2.5.  Secure Network Operations

   The kernel would then take care of accurate
   demultiplexing upon receive, and certificate installed in the previous step can be used for all
   subsequent transmission operations.  For example, to determine the
   correct interface.

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

   Some operating systems on which
   the domain: If a Registrar need be implemented may
   find need for neighbor has a virtual interface per Join Proxy to be problematic.
   There are other mechanism which certificate from the same trust
   anchor it can make be done.

   If assumed "inside" the IPIP decapsulator same organization; if not, as
   outside.  See also Appendix D.1.5.1.  The certificate 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 also 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
   used to the application as the UDP sockets
   are often not connected, securely establish a connection between devices and central
   control functions.  Also autonomic transactions can use the application will need domain
   certificates to specify the
   outgoing path on each packet send.

   Such an additional socket mechanism has not been standardized.
   Terminating L2TP connections over IPsec transport mode suffers from authenticate and/or encrypt direct interactions
   between devices.  The usage of the same challenges. domain certificates is outside
   scope for this document.

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
   Cisco

   Email: mbehring@cisco.com

   Steinthor Bjarnason
   Cisco

   Email: sbjarnas@cisco.com

   Kent Watsen
   Juniper Networks

   Email: kwatsen@juniper.net