Internet DRAFT - draft-ietf-netconf-trust-anchors

draft-ietf-netconf-trust-anchors







NETCONF Working Group                                          K. Watsen
Internet-Draft                                           Watsen Networks
Intended status: Standards Track                            10 July 2020
Expires: 11 January 2021


                   A YANG Data Model for a Truststore
                  draft-ietf-netconf-trust-anchors-12

Abstract

   This document defines a YANG 1.1 data model for configuring globally-
   accessible bags of certificates and public keys that can be
   referenced by other data models for trust.

Editorial Note (To be removed by RFC Editor)

   This draft contains placeholder values that need to be replaced with
   finalized values at the time of publication.  This note summarizes
   all of the substitutions that are needed.  No other RFC Editor
   instructions are specified elsewhere in this document.

   Artwork in this document contains shorthand references to drafts in
   progress.  Please apply the following replacements:

   *  "AAAA" --> the assigned RFC value for draft-ietf-netconf-crypto-
      types

   *  "BBBB" --> the assigned RFC value for this draft

   Artwork in this document contains placeholder values for the date of
   publication of this draft.  Please apply the following replacement:

   *  "2020-07-10" --> the publication date of this draft

   The following Appendix section is to be removed prior to publication:

   *  Appendix A.  Change Log

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.



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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on 11 January 2021.

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   This document is subject to BCP 78 and the IETF Trust's Legal
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   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Relation to other RFCs  . . . . . . . . . . . . . . . . .   3
     1.2.  Specification Language  . . . . . . . . . . . . . . . . .   5
     1.3.  Adherence to the NMDA . . . . . . . . . . . . . . . . . .   5
   2.  The "ietf-truststore" Module  . . . . . . . . . . . . . . . .   5
     2.1.  Data Model Overview . . . . . . . . . . . . . . . . . . .   5
     2.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   9
     2.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  18
   3.  Support for Built-in Trust Anchors  . . . . . . . . . . . . .  25
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  28
     4.1.  Data at Rest  . . . . . . . . . . . . . . . . . . . . . .  28
     4.2.  The "ietf-truststore" YANG Module . . . . . . . . . . . .  29
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  29
     5.1.  The "IETF XML" Registry . . . . . . . . . . . . . . . . .  29
     5.2.  The "YANG Module Names" Registry  . . . . . . . . . . . .  29
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  30
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  30
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  30
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  32
     A.1.  00 to 01  . . . . . . . . . . . . . . . . . . . . . . . .  32
     A.2.  01 to 02  . . . . . . . . . . . . . . . . . . . . . . . .  32
     A.3.  02 to 03  . . . . . . . . . . . . . . . . . . . . . . . .  32
     A.4.  03 to 04  . . . . . . . . . . . . . . . . . . . . . . . .  33
     A.5.  04 to 05  . . . . . . . . . . . . . . . . . . . . . . . .  33
     A.6.  05 to 06  . . . . . . . . . . . . . . . . . . . . . . . .  33



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     A.7.  06 to 07  . . . . . . . . . . . . . . . . . . . . . . . .  33
     A.8.  07 to 08  . . . . . . . . . . . . . . . . . . . . . . . .  33
     A.9.  08 to 09  . . . . . . . . . . . . . . . . . . . . . . . .  34
     A.10. 09 to 10  . . . . . . . . . . . . . . . . . . . . . . . .  34
     A.11. 10 to 11  . . . . . . . . . . . . . . . . . . . . . . . .  34
     A.12. 11 to 12  . . . . . . . . . . . . . . . . . . . . . . . .  34
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  35
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  35

1.  Introduction

   This document defines a YANG 1.1 [RFC7950] data model for configuring
   globally-accessible bags of certificates and public keys that can be
   referenced by other data models for trust.

1.1.  Relation to other RFCs

   This document presents one or more YANG modules [RFC7950] that are
   part of a collection of RFCs that work together to define
   configuration modules for clients and servers of both the NETCONF
   [RFC6241] and RESTCONF [RFC8040] protocols.

   The modules have been defined in a modular fashion to enable their
   use by other efforts, some of which are known to be in progress at
   the time of this writing, with many more expected to be defined in
   time.

   The relationship between the various RFCs in the collection is
   presented in the below diagram.  The labels in the diagram represent
   the primary purpose provided by each RFC.  Links the each RFC are
   provided below the diagram.




















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                                  crypto-types
                                    ^      ^
                                   /        \
                                  /          \
                         truststore         keystore
                          ^     ^             ^  ^
                          |     +---------+   |  |
                          |               |   |  |
                          |      +------------+  |
   tcp-client-server      |     /         |      |
      ^    ^        ssh-client-server     |      |
      |    |           ^            tls-client-server
      |    |           |              ^     ^        http-client-server
      |    |           |              |     |                 ^
      |    |           |        +-----+     +---------+       |
      |    |           |        |                     |       |
      |    +-----------|--------|--------------+      |       |
      |                |        |              |      |       |
      +-----------+    |        |              |      |       |
                  |    |        |              |      |       |
                  |    |        |              |      |       |
               netconf-client-server       restconf-client-server

   +=======================+===========================================+
   | Label in Diagram      | Originating RFC                           |
   +=======================+===========================================+
   | crypto-types          | [I-D.ietf-netconf-crypto-types]           |
   +-----------------------+-------------------------------------------+
   | truststore            | [I-D.ietf-netconf-trust-anchors]          |
   +-----------------------+-------------------------------------------+
   | keystore              | [I-D.ietf-netconf-keystore]               |
   +-----------------------+-------------------------------------------+
   | tcp-client-server     | [I-D.ietf-netconf-tcp-client-server]      |
   +-----------------------+-------------------------------------------+
   | ssh-client-server     | [I-D.ietf-netconf-ssh-client-server]      |
   +-----------------------+-------------------------------------------+
   | tls-client-server     | [I-D.ietf-netconf-tls-client-server]      |
   +-----------------------+-------------------------------------------+
   | http-client-server    | [I-D.ietf-netconf-http-client-server]     |
   +-----------------------+-------------------------------------------+
   | netconf-client-server | [I-D.ietf-netconf-netconf-client-server]  |
   +-----------------------+-------------------------------------------+
   |restconf-client-server | [I-D.ietf-netconf-restconf-client-server] |
   +-----------------------+-------------------------------------------+

                       Table 1: Label to RFC Mapping





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1.2.  Specification Language

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

1.3.  Adherence to the NMDA

   This document in compliant with the Network Management Datastore
   Architecture (NMDA) [RFC8342].  For instance, trust anchors installed
   during manufacturing (e.g., for trusted well-known services), are
   expected to appear in <operational> (see Section 3).

2.  The "ietf-truststore" Module

   This section defines a YANG 1.1 [RFC7950] module that defines a
   "truststore" and groupings supporting downstream modules to reference
   the truststore or have locally-defined definitions.

2.1.  Data Model Overview

2.1.1.  Features

   The following diagram lists all the "feature" statements defined in
   the "ietf-truststore" module:

   Features:
     +-- truststore-supported
     +-- local-definitions-supported
     +-- certificates
     +-- public-keys

2.1.2.  Typedefs

   The following diagram lists the "typedef" statements defined in the
   "ietf-truststore" module:

   Typedefs:
     leafref
       +-- certificate-bag-ref
       +-- certificate-ref
       +-- public-key-bag-ref
       +-- public-key-ref

   Comments:




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   *  All of the typedefs defined in the "ietf-truststore" module extend
      the base "leafref" type defined in [RFC7950].

   *  The leafrefs refer to certificates, public keys, and bags.  These
      typedefs are provided primarily as an aid to downstream modules
      that import the "ietf-truststore" module.

2.1.3.  Groupings

   The following diagram lists all the "grouping" statements defined in
   the "ietf-truststore" module:

   Groupings:
     +-- local-or-truststore-certs-grouping
     +-- local-or-truststore-public-keys-grouping
     +-- truststore-grouping

   Each of these groupings are presented in the following subsections.

2.1.3.1.  The "local-or-truststore-certs-grouping" Grouping

   The following tree diagram [RFC8340] illustrates the "local-or-
   truststore-certs-grouping" grouping:

     grouping local-or-truststore-certs-grouping
       +-- (local-or-truststore)
          +--:(local) {local-definitions-supported}?
          |  +-- local-definition
          |     +-- certificate* [name]
          |        +-- name?                            string
          |        +---u ct:trust-anchor-cert-grouping
          +--:(truststore) {truststore-supported,certificates}?
             +-- truststore-reference?   ts:certificate-bag-ref

   Comments:

   *  The "local-or-truststore-certs-grouping" grouping is provided
      soley as convenience to downstream modules that wish to offer an
      option as to if a bag of certificates can be defined locally or as
      a reference to a bag in the truststore.

   *  A "choice" statement is used to expose the various options.  Each
      option is enabled by a "feature" statement.  Additional "case"
      statements MAY be augmented in if, e.g., there is a need to
      reference a bag in an alternate location.






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   *  For the "local-definition" option, the "certificate" node uses the
      "trust-anchor-cert-grouping" grouping discussed in Section 2.1.3.6
      of [I-D.ietf-netconf-crypto-types].

   *  For the "truststore" option, the "truststore-reference" is an
      instance of the "certificate-bag-ref" discussed in Section 2.1.2.

2.1.3.2.  The "local-or-truststore-public-keys-grouping" Grouping

   The following tree diagram [RFC8340] illustrates the "local-or-
   truststore-public-keys-grouping" grouping:

     grouping local-or-truststore-public-keys-grouping
       +-- (local-or-truststore)
          +--:(local) {local-definitions-supported}?
          |  +-- local-definition
          |     +-- public-key* [name]
          |        +-- name?                     string
          |        +---u ct:public-key-grouping
          +--:(truststore) {truststore-supported,public-keys}?
             +-- truststore-reference?   ts:public-key-bag-ref

   Comments:

   *  The "local-or-truststore-public-keys-grouping" grouping is
      provided soley as convenience to downstream modules that wish to
      offer an option as to if a bag of public keys can be defined
      locally or as a reference to a bag in the truststore.

   *  A "choice" statement is used to expose the various options.  Each
      option is enabled by a "feature" statement.  Additional "case"
      statements MAY be augmented in if, e.g., there is a need to
      reference a bag in an alternate location.

   *  For the "local-definition" option, the "public-key" node uses the
      "public-key-grouping" grouping discussed in Section 2.1.3.3 of
      [I-D.ietf-netconf-crypto-types].

   *  For the "truststore" option, the "truststore-reference" is an
      instance of the "certificate-bag-ref" discussed in Section 2.1.2.

2.1.3.3.  The "truststore-grouping" Grouping

   The following tree diagram [RFC8340] illustrates the "truststore-
   grouping" grouping:






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     grouping truststore-grouping
       +-- certificate-bags! {certificates}?
       |  +-- certificate-bag* [name]
       |     +-- name?          string
       |     +-- description?   string
       |     +-- certificate* [name]
       |        +-- name?                            string
       |        +---u ct:trust-anchor-cert-grouping
       +-- public-key-bags! {public-keys}?
          +-- public-key-bag* [name]
             +-- name?          string
             +-- description?   string
             +-- public-key* [name]
                +-- name?                     string
                +---u ct:public-key-grouping

   Comments:

   *  The "truststore-grouping" grouping is defines a truststore
      instance as being composed of certificates and/or public keys,
      both of which are enabled by "feature" statements.  The stucture
      supporting certificates and public keys is essentially the same,
      having an outer list of "bags" containing in inner list of objects
      (certificates or public keys).  The bags enable trust anchors
      serving a common purpose to be grouped referenced together.

   *  For certificates, each certificate is defined by the "trust-
      anchor-cert-grouping" grouping Section 2.1.3.6 of
      [I-D.ietf-netconf-crypto-types].  Thus the "cert-data" node is a
      CMS structure that can be composed of a chain of one or more
      certificates.  Additionally, the "certificate-expiration"
      notification enables the server to alert clients when certificates
      are nearing or have already expired.

   *  For public keys, each public key is defined by the "public-key-
      grouping" grouping Section 2.1.3.3 of
      [I-D.ietf-netconf-crypto-types].  Thus the "public-key" node can
      be one of any number of structures specified by the "public-key-
      format" identity node.

2.1.4.  Protocol-accessible Nodes

   The following diagram lists all the protocol-accessible nodes defined
   in the "ietf-truststore" module:







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   module: ietf-truststore
     +--rw truststore
        +--rw certificate-bags! {certificates}?
        |  +--rw certificate-bag* [name]
        |     +--rw name           string
        |     +--rw description?   string
        |     +--rw certificate* [name]
        |        +--rw name                      string
        |        +--rw cert-data                 trust-anchor-cert-cms
        |        +---n certificate-expiration
        |           +-- expiration-date    yang:date-and-time
        +--rw public-key-bags! {public-keys}?
           +--rw public-key-bag* [name]
              +--rw name           string
              +--rw description?   string
              +--rw public-key* [name]
                 +--rw name                 string
                 +--rw public-key-format    identityref
                 +--rw public-key           binary

   Comments:

   *  Protocol-accessible nodes are those nodes that are accessible when
      the module is "implemented", as described in Section 5.6.5 of
      [RFC7950].

   *  For the "ietf-truststore" module, the protcol-accessible nodes are
      an instance of the "truststore-grouping" discussed in
      Section 2.1.3.3 grouping.

   *  The reason for why "truststore-grouping" exists separate from the
      protocol-accessible nodes definition is so as to enable instances
      of the truststore to be instantiated in other locations, as may be
      needed or desired by some modules.

2.2.  Example Usage

   The examples in this section are encoded using XML, such as might be
   the case when using the NETCONF protocol.  Other encodings MAY be
   used, such as JSON when using the RESTCONF protocol.

2.2.1.  A Truststore Instance

   This section presents an example illustrating trust anchors in
   <intended>, as per Section 2.1.4.  Please see Section 3 for an
   example illustrating built-in values in <operational>.





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   The example contained in this secton defines eight bags of trust
   anchors.  There are four certificate-based bags and four public key
   based bags.  The following diagram provides an overview of contents
   in the example:

   Certificate Bags
     +-- CA certificates for authenticating a set a remote servers
     +-- EE certificates for authenticating a set a remote servers
     +-- CA certificates for authenticating a set a remote clients
     +-- EE certificates for authenticating a set a remote clients

   Public Key Bags
     +-- SSH keys to authenticate a set of remote SSH server
     +-- SSH keys to authenticate a set of remote SSH clients
     +-- Raw public keys to authenticate a set of remote SSH server
     +-- Raw public keys to authenticate a set of remote SSH clients

   Following is the full example:

   <truststore
     xmlns="urn:ietf:params:xml:ns:yang:ietf-truststore"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">

     <!-- A bag of Certificate Bags -->
     <certificate-bags>

       <!-- CA Certs for Authenticating Servers Using Private PKIs -->
       <certificate-bag>
         <name>trusted-server-ca-certs</name>
         <description>
           Trust anchors (i.e. CA certs) used to authenticate server
           certificates.  A server certificate is authenticated if its
           end-entity certificate has a chain of trust to one of these
           certificates.
         </description>
         <certificate>
           <name>Server Cert Issuer #1</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
         <certificate>
           <name>Server Cert Issuer #2</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificate-bag>

       <!-- End Entity Certs for Authenticating Servers -->
       <certificate-bag>
         <name>trusted-server-ee-certs</name>



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         <description>
           Specific end-entity certificates used to authenticate server
           certificates.  A server certificate is authenticated if its
           end-entity certificate is an exact match to one of these
           certificates.
         </description>
         <certificate>
           <name>My Application #1</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
         <certificate>
           <name>My Application #2</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificate-bag>

       <!-- CA Certs for Authenticating Clients -->
       <certificate-bag>
         <name>trusted-client-ca-certs</name>
         <description>
           Trust anchors (i.e. CA certs) used to authenticate client
           certificates.  A client certificate is authenticated if its
           end-entity certificate has a chain of trust to one of these
           certificates.
         </description>
         <certificate>
           <name>Client Identity Issuer #1</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
         <certificate>
           <name>Client Identity Issuer #2</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificate-bag>

       <!-- Entity Certs for Authenticating Clients -->
       <certificate-bag>
         <name>trusted-client-ee-certs</name>
         <description>
           Specific end-entity certificates used to authenticate client
           certificates.  A client certificate is authenticated if its
           end-entity certificate is an exact match to one of these
           certificates.
         </description>
         <certificate>
           <name>George Jetson</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>



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         <certificate>
           <name>Fred Flintstone</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificate-bag>
     </certificate-bags>

     <!-- A List of Public Key Bags -->
     <public-key-bags>

       <!-- Public Keys for Authenticating SSH Servers -->
       <public-key-bag>
         <name>trusted-ssh-public-keys</name>
         <description>
           Specific SSH public keys used to authenticate SSH server
           public keys.  An SSH server public key is authenticated if
           its public key is an exact match to one of these public keys.

           This list of SSH public keys is analogous to OpenSSH's
           "/etc/ssh/ssh_known_hosts" file.
         </description>
         <public-key>
           <name>corp-fw1</name>
           <public-key-format>
             ct:ssh-public-key-format
           </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
         <public-key>
           <name>corp-fw2</name>
           <public-key-format>
             ct:ssh-public-key-format
           </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
       </public-key-bag>

       <!-- SSH Public Keys for Authenticating Application A -->
       <public-key-bag>
         <name>SSH Public Keys for Application A</name>
         <description>
           SSH public keys used to authenticate application A's SSH
           public keys.  An SSH public key is authenticated if it
           is an exact match to one of these public keys.
         </description>
         <public-key>
           <name>Application Instance #1</name>
           <public-key-format>



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             ct:ssh-public-key-format
           </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
         <public-key>
           <name>Application Instance #2</name>
           <public-key-format>
             ct:ssh-public-key-format
           </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
       </public-key-bag>

       <!-- Raw Public Keys for TLS Servers -->
       <public-key-bag>
         <name>Raw Public Keys for TLS Servers</name>
         <public-key>
           <name>Raw Public Key #1</name>
           <public-key-format>
             ct:subject-public-key-info-format</public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
         <public-key>
           <name>Raw Public Key #2</name>
           <public-key-format>
             ct:subject-public-key-info-format
           </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
       </public-key-bag>

       <!-- Raw Public Keys for TLS Clients -->
       <public-key-bag>
         <name>Raw Public Keys for TLS Clients</name>
         <public-key>
           <name>Raw Public Key #1</name>
           <public-key-format>
             ct:subject-public-key-info-format
           </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
         <public-key>
           <name>Raw Public Key #2</name>
           <public-key-format>
             ct:subject-public-key-info-format
         </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>



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       </public-key-bag>
     </public-key-bags>
   </truststore>

2.2.2.  A Certificate Expiration Notification

   The following example illustrates the "certificate-expiration"
   notification (per Section 2.1.3.4 of [I-D.ietf-netconf-crypto-types])
   for a certificate configured in the truststore in Section 2.2.1.

   =============== NOTE: '\' line wrapping per RFC 8792 ================

   <notification
     xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
     <eventTime>2018-05-25T00:01:00Z</eventTime>
     <truststore xmlns="urn:ietf:params:xml:ns:yang:ietf-truststore">
       <certificate-bags>
         <certificate-bag>
           <name>trusted-client-ee-certs</name>
           <certificate>
             <name>George Jetson</name>
             <certificate-expiration>
               <expiration-date>2018-08-05T14:18:53-05:00</expiration-d\
   ate>
             </certificate-expiration>
           </certificate>
         </certificate-bag>
       </certificate-bags>
     </truststore>
   </notification>

2.2.3.  The "Local or Truststore" Groupings

   This section illustrates the various "local-or-truststore" groupings
   defined in the "ietf-truststore" module, specifically the "local-or-
   truststore-certs-grouping" (Section 2.1.3.1) and "local-or-
   truststore-public-keys-grouping" (Section 2.1.3.2), groupings.

   The following non-normative module is defined to illustrate these
   groupings:

   module ex-truststore-usage {
     yang-version 1.1;

     namespace "http://example.com/ns/example-truststore-usage";
     prefix "etu";

     import ietf-truststore {



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       prefix ts;
       reference
         "RFC BBBB: A YANG Data Model for a Truststore";
     }

     organization
      "Example Corporation";

     contact
      "Author: YANG Designer <mailto:yang.designer@example.com>";

     description
      "This module illustrates notable groupings defined in
       the 'ietf-truststore' module.";

     revision "2020-07-10" {
       description
        "Initial version";
       reference
         "RFC BBBB: A YANG Data Model for a Truststore";
     }

     container truststore-usage {
       description
         "An illustration of the various truststore groupings.";

       list cert {
         key name;
         leaf name {
           type string;
           description
             "An arbitrary name for this cert.";
         }
         uses ts:local-or-truststore-certs-grouping;
         description
           "An cert that may be configured locally or be
            a reference to a cert in the truststore.";
       }

       list public-key {
         key name;
         leaf name {
           type string;
           description
             "An arbitrary name for this cert.";
         }
         uses ts:local-or-truststore-public-keys-grouping;
         description



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           "An public key that may be configured locally or be
            a reference to a public key in the truststore.";
       }
     }
   }

   The tree diagram [RFC8340] for this example module follows:

   module: ex-truststore-usage
     +--rw truststore-usage
        +--rw cert* [name]
        |  +--rw name                          string
        |  +--rw (local-or-truststore)
        |     +--:(local) {local-definitions-supported}?
        |     |  +--rw local-definition
        |     |     +--rw certificate* [name]
        |     |        +--rw name                      string
        |     |        +--rw cert-data
        |     |        |       trust-anchor-cert-cms
        |     |        +---n certificate-expiration
        |     |           +-- expiration-date    yang:date-and-time
        |     +--:(truststore) {truststore-supported,certificates}?
        |        +--rw truststore-reference?   ts:certificate-bag-ref
        +--rw public-key* [name]
           +--rw name                          string
           +--rw (local-or-truststore)
              +--:(local) {local-definitions-supported}?
              |  +--rw local-definition
              |     +--rw public-key* [name]
              |        +--rw name                 string
              |        +--rw public-key-format    identityref
              |        +--rw public-key           binary
              +--:(truststore) {truststore-supported,public-keys}?
                 +--rw truststore-reference?   ts:public-key-bag-ref

   The following example provides two equivalent instances of each
   grouping, the first being a reference to a truststore and the second
   being locally-defined.  The instance having a reference to a
   truststore is consistent with the truststore defined in
   Section 2.2.1.  The two instances are equivalent, as the locally-
   defined instance example contains the same values defined by the
   truststore instance referenced by its sibling example.









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   =============== NOTE: '\' line wrapping per RFC 8792 ================

   <truststore-usage
     xmlns="http://example.com/ns/example-truststore-usage"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">

     <!-- The following two equivalent examples illustrate   -->
     <!-- the "local-or-truststore-certs-grouping" grouping: -->

     <cert>
       <name>example 1a</name>
       <truststore-reference>trusted-client-ca-certs</truststore-refere\
   nce>
     </cert>

     <cert>
       <name>example 1b</name>
       <local-definition>
         <name>my-trusted-client-ca-certs</name>
         <certificate>
           <name>Client Identity Issuer #1</name>
           <cert>base64encodedvalue==</cert>
         </certificate>
         <certificate>
           <name>Client Identity Issuer #2</name>
           <cert>base64encodedvalue==</cert>
         </certificate>
       </local-definition>
     </cert>


     <!-- The following two equivalent examples illustrate the -->
     <!-- "local-or-truststore-public-keys-grouping" grouping: -->

     <public-key>
       <name>example 2a</name>
       <truststore-reference>trusted-ssh-public-keys</truststore-refere\
   nce>
     </public-key>

     <public-key>
       <name>example 2b</name>
       <local-definition>
         <name>trusted-ssh-public-keys</name>
         <public-key>
           <name>corp-fw1</name>
           <public-key-format>
             ct:ssh-public-key-format



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           </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
         <public-key>
           <name>corp-fw2</name>
           <public-key-format>
             ct:ssh-public-key-format
           </public-key-format>
           <public-key>base64encodedvalue==</public-key>
         </public-key>
       </local-definition>
     </public-key>

   </truststore-usage>

2.3.  YANG Module

   This YANG module imports modules from [RFC8341] and
   [I-D.ietf-netconf-crypto-types].

   <CODE BEGINS> file "ietf-truststore@2020-07-10.yang"

   module ietf-truststore {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-truststore";
     prefix ts;

     import ietf-netconf-acm {
       prefix nacm;
       reference
         "RFC 8341: Network Configuration Access Control Model";
     }

     import ietf-crypto-types {
       prefix ct;
       reference
         "RFC AAAA: YANG Data Types and Groupings for Cryptography";
     }

     organization
       "IETF NETCONF (Network Configuration) Working Group";

     contact
       "WG Web  : <http://datatracker.ietf.org/wg/netconf/>
        WG List : <mailto:netconf@ietf.org>
        Author  : Kent Watsen <kent+ietf@watsen.net>";

     description



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       "This module defines a Truststore to centralize management
        of trust anchors including certificates and public keys.

        Copyright (c) 2020 IETF Trust and the persons identified
        as authors of the code. All rights reserved.

        Redistribution and use in source and binary forms, with
        or without modification, is permitted pursuant to, and
        subject to the license terms contained in, the Simplified
        BSD License set forth in Section 4.c of the IETF Trust's
        Legal Provisions Relating to IETF Documents
        (https://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC BBBB
        (https://www.rfc-editor.org/info/rfcBBBB); see the RFC
        itself for full legal notices.

        The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
        'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
        'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document
        are to be interpreted as described in BCP 14 (RFC 2119)
        (RFC 8174) when, and only when, they appear in all
        capitals, as shown here.";

     revision 2020-07-10 {
       description
         "Initial version";
       reference
         "RFC BBBB: A YANG Data Model for a Truststore";
     }

     /****************/
     /*   Features   */
     /****************/

     feature truststore-supported {
       description
         "The 'truststore-supported' feature indicates that the
          server supports the Truststore (i.e., implements the
          'ietf-truststore' module).";
     }

     feature local-definitions-supported {
       description
         "The 'local-definitions-supported' feature indicates that
          the server supports locally-defined trust anchors.";
     }




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     feature certificates {
       description
         "The 'certificates' feature indicates that the server
          implements the /truststore/certificate-bags subtree.";
     }

     feature public-keys {
       description
         "The 'public-keys' feature indicates that the server
          implements the /truststore/public-key-bags subtree.";
     }

     /****************/
     /*   Typedefs   */
     /****************/

     typedef certificate-bag-ref {
       type leafref {
         path "/ts:truststore/ts:certificate-bags/"
              + "ts:certificate-bag/ts:name";
       }
       description
         "This typedef defines a reference to a certificate bag
          defined in the Truststore.";
     }

     typedef certificate-ref {
       type leafref {
         path "/ts:truststore/certificate-bags/certificate-bag" +
              "[name = current()/../certificate-bag]/certificate/name";
       }
       description
         "This typedef define a reference to a specific certificate
          in a certificate bag defined in the Truststore.  This
          typedef requires that there exist a sibling 'leaf' node
          called 'certificate-bag' that SHOULD have the typedef
          'certificate-bag-ref'.";
     }

     typedef public-key-bag-ref {
       type leafref {
         path "/ts:truststore/ts:public-key-bags/"
              + "ts:public-key-bag/ts:name";
       }
       description
         "This typedef define a reference to a public key bag
          defined in the Truststore.";
     }



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     typedef public-key-ref {
       type leafref {
         path "/ts:truststore/public-key-bags/public-key-bag" +
              "[name = current()/../public-key-bag]/" +
              "public-key/name";
       }
       description
         "This typedef define a reference to a specific public key
          in a public key bag defined in the Truststore.  This
          typedef requires that there exist a sibling 'leaf' node
          called 'public-key-bag' that SHOULD have the typedef
          'public-key-bag-ref'.";
     }


     /*****************/
     /*   Groupings   */
     /*****************/

     grouping local-or-truststore-certs-grouping {
       description
         "A grouping that allows the certificates to be either
          configured locally, within the using data model, or be a
          reference to a certificate bag stored in the Truststore.";
       choice local-or-truststore {
         nacm:default-deny-write;
         mandatory true;
         case local {
           if-feature "local-definitions-supported";
           container local-definition {
             description
               "A container for locally configured trust anchor
                certificates.";
             list certificate {
               key "name";
               min-elements 1;
               description
                 "A trust anchor certificate.";
               leaf name {
                 type string;
                 description
                   "An arbitrary name for this certificate.";
               }
               uses ct:trust-anchor-cert-grouping {
                 refine "cert-data" {
                   mandatory true;
                 }
               }



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             }
           }
         }
         case truststore {
           if-feature "truststore-supported";
           if-feature "certificates";
           leaf truststore-reference {
             type ts:certificate-bag-ref;
             description
               "A reference to a certificate bag that exists in the
                Truststore.";
           }
         }
         description
           "A choice between an inlined definition and a definition
            that exists in the Truststore.";
       }
     }


     grouping local-or-truststore-public-keys-grouping {
       description
         "A grouping that allows the public keys to be either
          configured locally, within the using data model, or be a
          reference to a public key bag stored in the Truststore.";
       choice local-or-truststore {
         nacm:default-deny-write;
         mandatory true;
         case local {
           if-feature "local-definitions-supported";
           container local-definition {
             description
               "Container to hold local public key definitions.";
             list public-key {
               key name;
               description
                 "A public key definition.";
               leaf name {
                 type string;
                 description
                   "An arbitrary name for this public key.";
               }
               uses ct:public-key-grouping;
             }
           }
         }
         case truststore {
           if-feature "truststore-supported";



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           if-feature "public-keys";
           leaf truststore-reference {
             type ts:public-key-bag-ref;
             description
               "A reference to a bag of public keys that exist
                in the Truststore.";
           }
         }
         description
           "A choice between an inlined definition and a definition
            that exists in the Truststore.";
       }
     }

     grouping truststore-grouping {
       description
         "Grouping definition enables use in other contexts.  Where
          used, implementations SHOULD augment new 'case' statements
          into the local-or-truststore 'choice' statements to supply
          leafrefs to the model-specific location.";
       container certificate-bags {
         nacm:default-deny-write;
         if-feature "certificates";
         presence
           "Indicates that certificate bags have been configured.";
         description
           "A collection of certificate bags.";
         list certificate-bag {
           key "name";
           min-elements 1;
           description
             "A bag of certificates.  Each bag of certificates SHOULD
              be for a specific purpose.  For instance, one bag could
              be used to authenticate a specific set of servers, while
              another could be used to authenticate a specific set of
              clients.";
           leaf name {
             type string;
             description
               "An arbitrary name for this bag of certificates.";
           }
           leaf description {
             type string;
             description
               "A description for this bag of certificates.  The
               intended purpose for the bag SHOULD be described.";
           }
           list certificate {



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             key "name";
             min-elements 1;
             description
               "A trust anchor certificate.";
             leaf name {
               type string;
               description
                 "An arbitrary name for this certificate.";
             }
             uses ct:trust-anchor-cert-grouping {
               refine "cert-data" {
                 mandatory true;
               }
             }
           }
         }
       }
       container public-key-bags {
         nacm:default-deny-write;
         if-feature "public-keys";
         presence
           "Indicates that public keys have been configured.";
         description
           "A collection of public key bags.";
         list public-key-bag {
           key "name";
           min-elements 1;
           description
             "A bag of public keys.  Each bag of keys SHOULD be for
              a specific purpose.  For instance, one bag could be used
              authenticate a specific set of servers, while another
              could be used to authenticate a specific set of clients.";
           leaf name {
             type string;
             description
               "An arbitrary name for this bag of public keys.";
           }
           leaf description {
             type string;
             description
               "A description for this bag public keys.  The
                intended purpose for the bag SHOULD be described.";
           }
           list public-key {
             key "name";
             min-elements 1;
             description
               "A public key.";



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             leaf name {
               type string;
               description
                 "An arbitrary name for this public key.";
             }
             uses ct:public-key-grouping;
           }
         }
       }
     }

     /*********************************/
     /*   Protocol accessible nodes   */
     /*********************************/

     container truststore {
       nacm:default-deny-write;
       description
         "The Truststore contains bags of certificates and
          public keys.";
       uses truststore-grouping;
     }
   }

   <CODE ENDS>

3.  Support for Built-in Trust Anchors

   In some implementations, a server may define some built-in trust
   anchors.  For instance, there may be built-in trust anchors enabling
   the server to securely connect to well-known services (e.g., an SZTP
   [RFC8572] bootstrap server) or public CA certificates to connect to
   arbitrary services using public PKI.

   Built-in trust anchors are expected to be set by a vendor-specific
   process.  Any ability for operators to modify built-in trust anchors
   is outside the scope of this document.

   As built-in trust anchors are provided by the system, they are
   present in <operational>.  The example below illustrates what the
   Truststore in <operational> might look like for a server in its
   factory default state.









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   <truststore
     xmlns="urn:ietf:params:xml:ns:yang:ietf-truststore"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types"
     xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
     or:origin="or:intended">
     <certificate-bags>

       <certificate-bag or:origin="or:system">
         <name>Built-In Manufacturer CA Certificates</name>
         <description>
           Certificates built into the device for authenticating
           manufacturer-signed objects, such as TLS server certificates,
           vouchers, etc.
         </description>
         <certificate>
           <name>Manufacturer Root CA Cert</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificate-bag>

       <certificate-bag or:origin="or:system">
         <name>Built-In Public CA Certificates</name>
         <description>
           Certificates built into the device for authenticating
           certificates issued by public certificate authorities,
           such as the end-entity certificate for web servers.
         </description>
         <certificate>
           <name>Public Root CA Cert 1</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
         <certificate>
           <name>Public Root CA Cert 2</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
         <certificate>
           <name>Public Root CA Cert 3</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificate-bag>

     </certificate-bags>
   </truststore>








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   In order for the built-in trust anchors to be referenced by
   configuration, the referenced certificates MUST first be copied into
   <running>.  The certificates SHOULD be copied into <running> using
   the same "key" values, so that the server can bind them to the built-
   in entries.

   Built-in certificates MAY be copied into other parts of the
   configuration but, by doing so, they lose their association to the
   built-in entries and any assurances afforded by knowing they are the
   built-in certificates.

   Only the referenced certificates need to be copied; that is, the
   certificates in <running> MAY be a subset of the built-in
   certificates define in <operational>.  No certificates may be added
   or changed; that is, the certificates in <running> MUST be a subset
   (which includes the whole of the set) of the built-in certificates
   define in <operational>.

   A server MUST reject attempts to modify any aspect of built-in trust
   anchors, both the certificates themselves and the bags that contain
   them.  That these certificates are "configured" in <running> is an
   illusion, as they are strictly a read-only subset of that which must
   already exist in <operational>.

   The following example illustrates how a single built-in public CA
   certificate from the previous example has been propagated to
   <running>:
























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   <truststore
     xmlns="urn:ietf:params:xml:ns:yang:ietf-truststore"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
     <certificate-bags>

       <certificate-bag>
         <name>Built-In Public CA Certificates</name>
         <description>
           Certificates built into the device for authenticating
           certificates issued by public certificate authorities,
           such as the end-entity certificate for web servers.

           Only the subset of the certificates that are referenced
           by other configuration nodes need to be copied.  For
           instance, only "Public Root CA Cert 3" is present here.

           No new certificates can be added, nor existing certificate
           values changed.  Missing certificates have no effect on
           "operational" when the configuration is applied.
         </description>
         <certificate>
           <name>Public Root CA Cert 3</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificate-bag>

     </certificate-bags>
   </truststore>

4.  Security Considerations

4.1.  Data at Rest

   The YANG module defined in this document defines a mechanism called a
   "truststore" that, by its name, suggests that it will protect its
   contents from unauthorized modification.

   Security controls for the API (i.e., data in motion) are discussed in
   Section 4.2, but controls for the data at rest cannot be specified by
   the YANG module.

   In order to satisfy the expectations of a "truststore", it is
   RECOMMENDED that implementations ensure that the truststore contents
   are signed when persisted to non-volatile memory, to prevent
   unauthorized modifications from being made undetected.






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4.2.  The "ietf-truststore" YANG Module

   The YANG module defined in this document is designed to be accessed
   via YANG based management protocols, such as NETCONF [RFC6241] and
   RESTCONF [RFC8040].  Both of these protocols have mandatory-to-
   implement secure transport layers (e.g., SSH, TLS) with mutual
   authentication.

   The NETCONF access control model (NACM) [RFC8341] provides the means
   to restrict access for particular users to a pre-configured subset of
   all available protocol operations and content.

   None of the readable data nodes defined in this YANG module are
   considered sensitive or vulnerable in network environments.  The NACM
   "default-deny-all" extension has not been set for any data nodes
   defined in this module.

   All of the writable data nodes defined by this module, both in the
   "grouping" statements as well as the protocol-accessible "truststore"
   instance, may be considered sensitive or vulnerable in some network
   environments.  For instance, any modification to a trust anchor or
   reference to a trust anchor may dramatically alter the implemented
   security policy.  For this reason, the NACM extension "default-deny-
   write" has been set for all data nodes defined in this module.

   This module does not define any RPCs, actions, or notifications, and
   thus the security consideration for such is not provided here.

5.  IANA Considerations

5.1.  The "IETF XML" Registry

   This document registers one URI in the "ns" subregistry of the IETF
   XML Registry [RFC3688].  Following the format in [RFC3688], the
   following registration is requested:

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

5.2.  The "YANG Module Names" Registry

   This document registers one YANG module in the YANG Module Names
   registry [RFC6020].  Following the format in [RFC6020], the the
   following registration is requested:






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      name:         ietf-truststore
      namespace:    urn:ietf:params:xml:ns:yang:ietf-truststore
      prefix:       ts
      reference:    RFC BBBB

6.  References

6.1.  Normative References

   [I-D.ietf-netconf-crypto-types]
              Watsen, K., "Common YANG Data Types for Cryptography",
              Work in Progress, Internet-Draft, draft-ietf-netconf-
              crypto-types-15, 20 May 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-crypto-
              types-15>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.

6.2.  Informative References

   [I-D.ietf-netconf-http-client-server]
              Watsen, K., "YANG Groupings for HTTP Clients and HTTP
              Servers", Work in Progress, Internet-Draft, draft-ietf-
              netconf-http-client-server-03, 20 May 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-http-
              client-server-03>.

   [I-D.ietf-netconf-keystore]
              Watsen, K., "A YANG Data Model for a Keystore", Work in
              Progress, Internet-Draft, draft-ietf-netconf-keystore-17,
              20 May 2020, <https://tools.ietf.org/html/draft-ietf-
              netconf-keystore-17>.



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   [I-D.ietf-netconf-netconf-client-server]
              Watsen, K., "NETCONF Client and Server Models", Work in
              Progress, Internet-Draft, draft-ietf-netconf-netconf-
              client-server-19, 20 May 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-netconf-
              client-server-19>.

   [I-D.ietf-netconf-restconf-client-server]
              Watsen, K., "RESTCONF Client and Server Models", Work in
              Progress, Internet-Draft, draft-ietf-netconf-restconf-
              client-server-19, 20 May 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-restconf-
              client-server-19>.

   [I-D.ietf-netconf-ssh-client-server]
              Watsen, K. and G. Wu, "YANG Groupings for SSH Clients and
              SSH Servers", Work in Progress, Internet-Draft, draft-
              ietf-netconf-ssh-client-server-19, 20 May 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-ssh-
              client-server-19>.

   [I-D.ietf-netconf-tcp-client-server]
              Watsen, K. and M. Scharf, "YANG Groupings for TCP Clients
              and TCP Servers", Work in Progress, Internet-Draft, draft-
              ietf-netconf-tcp-client-server-06, 16 June 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-tcp-
              client-server-06>.

   [I-D.ietf-netconf-tls-client-server]
              Watsen, K. and G. Wu, "YANG Groupings for TLS Clients and
              TLS Servers", Work in Progress, Internet-Draft, draft-
              ietf-netconf-tls-client-server-19, 20 May 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-tls-
              client-server-19>.

   [I-D.ietf-netconf-trust-anchors]
              Watsen, K., "A YANG Data Model for a Truststore", Work in
              Progress, Internet-Draft, draft-ietf-netconf-trust-
              anchors-10, 20 May 2020, <https://tools.ietf.org/html/
              draft-ietf-netconf-trust-anchors-10>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.







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   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

   [RFC8572]  Watsen, K., Farrer, I., and M. Abrahamsson, "Secure Zero
              Touch Provisioning (SZTP)", RFC 8572,
              DOI 10.17487/RFC8572, April 2019,
              <https://www.rfc-editor.org/info/rfc8572>.

Appendix A.  Change Log

   This section is to be removed before publishing as an RFC.

A.1.  00 to 01

   *  Added features "x509-certificates" and "ssh-host-keys".

   *  Added nacm:default-deny-write to "trust-anchors" container.

A.2.  01 to 02

   *  Switched "list pinned-certificate" to use the "trust-anchor-cert-
      grouping" from crypto-types.  Effectively the same definition as
      before.

A.3.  02 to 03

   *  Updated copyright date, boilerplate template, affiliation, folding
      algorithm, and reformatted the YANG module.



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A.4.  03 to 04

   *  Added groupings 'local-or-truststore-certs-grouping' and 'local-
      or-truststore-host-keys-grouping', matching similar definitions in
      the keystore draft.  Note new (and incomplete) "truststore" usage!

   *  Related to above, also added features 'truststore-supported' and
      'local-trust-anchors-supported'.

A.5.  04 to 05

   *  Renamed "trust-anchors" to "truststore"

   *  Removed "pinned." prefix everywhere, to match truststore rename

   *  Moved everything under a top-level 'grouping' to enable use in
      other contexts.

   *  Renamed feature from 'local-trust-anchors-supported' to 'local-
      definitions-supported' (same name used in keystore)

   *  Removed the "require-instance false" statement from the "*-ref"
      typedefs.

   *  Added missing "ssh-host-keys" and "x509-certificates" if-feature
      statements

A.6.  05 to 06

   *  Editorial changes only.

A.7.  06 to 07

   *  Added Henk Birkholz as a co-author (thanks Henk!)

   *  Added PSKs and raw public keys to Truststore.

A.8.  07 to 08

   *  Added new "Support for Built-in Trust Anchors" section.

   *  Removed spurious "uses ct:trust-anchor-certs-grouping" line.

   *  Removed PSK from model.







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A.9.  08 to 09

   *  Removed remaining PSK references from text.

   *  Wrapped each top-level list with a container.

   *  Introduced "bag" term.

   *  Merged "SSH Public Keys" and "Raw Public Keys" in a single "Public
      Keys" bag.  Consuming downstream modules (i.e., "ietf-[ssh/tls]-
      [client/server]) refine the "public-key-format" to be either SSH
      or TLS specific as needed.

A.10.  09 to 10

   *  Removed "algorithm" node from examples.

   *  Removed the no longer used statements supporting the old "ssh-
      public-key" and "raw-public-key" nodes.

   *  Added a "Note to Reviewers" note to first page.

A.11.  10 to 11

   *  Corrected module prefix registered in the IANA Considerations
      section.

   *  Modified 'local-or-truststore-certs-grouping' to use a list (not a
      leaf-list).

   *  Added new example section "The Local or Truststore Groupings".

   *  Clarified expected behavior for "built-in" certificates in
      <operational>

   *  Expanded "Data Model Overview section(s) [remove "wall" of tree
      diagrams].

   *  Updated the Security Considerations section.

A.12.  11 to 12

   *  Fixed a copy/paste issue in the "Data at Rest" Security
      Considerations section.







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Acknowledgements

   The authors especially thank Henk Birkholz for contributing YANG to
   the ietf-truststore module supporting raw public keys and PSKs (pre-
   shared or pairwise-symmetric keys).  While these contributions were
   eventually replaced by reusing the existing support for asymmetric
   and symmetric trust anchors, respectively, it was only thru Henk's
   initiative that the WG was able to come to that result.

   The authors additionally thank the following for helping give shape
   to this work (ordered by first name): Balazs Kovacs, Eric Voit,
   Juergen Schoenwaelder, Liang Xia, Martin Bjorklund, and Nick Hancock.

Author's Address

   Kent Watsen
   Watsen Networks

   Email: kent+ietf@watsen.net
































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