Skip to main content

A YANG Data Model for a Keystore and Keystore Operations
draft-ietf-netconf-keystore-35

Document Type Active Internet-Draft (netconf WG)
Author Kent Watsen
Last updated 2024-09-18 (Latest revision 2024-03-16)
Replaces draft-ietf-netconf-system-keychain
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
Formats
Yang Validation 0 errors, 0 warnings
Reviews
Additional resources Yang catalog entry for ietf-keystore@2020-08-20.yang
Yang impact analysis for draft-ietf-netconf-keystore
Mailing list discussion
Stream WG state Submitted to IESG for Publication
Document shepherd Qin Wu
Shepherd write-up Show Last changed 2022-10-19
IESG IESG state RFC Ed Queue
Action Holders
(None)
Consensus boilerplate Yes
Telechat date (None)
Responsible AD Robert Wilton
Send notices to bill.wu@huawei.com, mjethanandani@gmail.com
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack
IANA expert review state Expert Reviews OK
RFC Editor RFC Editor state AUTH48-DONE
Details
draft-ietf-netconf-keystore-35
NETCONF Working Group                                          K. Watsen
Internet-Draft                                           Watsen Networks
Intended status: Standards Track                           16 March 2024
Expires: 17 September 2024

        A YANG Data Model for a Keystore and Keystore Operations
                     draft-ietf-netconf-keystore-35

Abstract

   This document presents a YANG module called "ietf-keystore" that
   enables centralized configuration of both symmetric and asymmetric
   keys.  The secret value for both key types may be encrypted or
   hidden.  Asymmetric keys may be associated with certificates.
   Notifications are sent when certificates are about to expire.

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

   *  CCCC --> 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:

   *  2024-03-16 --> the publication date of this draft

   The "Relation to other RFCs" section Section 1.1 contains the text
   "one or more YANG modules" and, later, "modules".  This text is
   sourced from a file in a context where it is unknown how many modules
   a draft defines.  The text is not wrong as is, but it may be improved
   by stating more directly how many modules are defined.

   The "Relation to other RFCs" section Section 1.1 contains a self-
   reference to this draft, along with a corresponding reference in the
   Appendix.  Please replace the self-reference in this section with
   "This RFC" (or similar) and remove the self-reference in the
   "Normative/Informative References" section, whichever it is in.

Watsen                  Expires 17 September 2024               [Page 1]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   Tree-diagrams in this draft may use the '\' line-folding mode defined
   in RFC 8792.  However, nicer-to-the-eye is when the '\\' line-folding
   mode is used.  The AD suggested suggested putting a request here for
   the RFC Editor to help convert "ugly" '\' folded examples to use the
   '\\' folding mode.  "Help convert" may be interpreted as, identify
   what looks ugly and ask the authors to make the adjustment.

   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/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 17 September 2024.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4

Watsen                  Expires 17 September 2024               [Page 2]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

     1.1.  Relation to other RFCs  . . . . . . . . . . . . . . . . .   5
     1.2.  Specification Language  . . . . . . . . . . . . . . . . .   6
     1.3.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   6
     1.4.  Adherence to the NMDA . . . . . . . . . . . . . . . . . .   7
     1.5.  Conventions . . . . . . . . . . . . . . . . . . . . . . .   7
   2.  The "ietf-keystore" Module  . . . . . . . . . . . . . . . . .   7
     2.1.  Data Model Overview . . . . . . . . . . . . . . . . . . .   7
     2.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .  16
     2.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  27
   3.  Support for Built-in Keys . . . . . . . . . . . . . . . . . .  36
   4.  Encrypting Keys in Configuration  . . . . . . . . . . . . . .  38
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  43
     5.1.  Security of Data at Rest and in Motion  . . . . . . . . .  43
     5.2.  Unconstrained Private Key Usage . . . . . . . . . . . . .  43
     5.3.  Considerations for the "ietf-keystore" YANG Module  . . .  43
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  45
     6.1.  The "IETF XML" Registry . . . . . . . . . . . . . . . . .  45
     6.2.  The "YANG Module Names" Registry  . . . . . . . . . . . .  45
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  45
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  45
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  46
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  48
     A.1.  00 to 01  . . . . . . . . . . . . . . . . . . . . . . . .  48
     A.2.  01 to 02  . . . . . . . . . . . . . . . . . . . . . . . .  48
     A.3.  02 to 03  . . . . . . . . . . . . . . . . . . . . . . . .  49
     A.4.  03 to 04  . . . . . . . . . . . . . . . . . . . . . . . .  49
     A.5.  04 to 05  . . . . . . . . . . . . . . . . . . . . . . . .  49
     A.6.  05 to 06  . . . . . . . . . . . . . . . . . . . . . . . .  49
     A.7.  06 to 07  . . . . . . . . . . . . . . . . . . . . . . . .  50
     A.8.  07 to 08  . . . . . . . . . . . . . . . . . . . . . . . .  50
     A.9.  08 to 09  . . . . . . . . . . . . . . . . . . . . . . . .  50
     A.10. 09 to 10  . . . . . . . . . . . . . . . . . . . . . . . .  50
     A.11. 10 to 11  . . . . . . . . . . . . . . . . . . . . . . . .  51
     A.12. 11 to 12  . . . . . . . . . . . . . . . . . . . . . . . .  51
     A.13. 12 to 13  . . . . . . . . . . . . . . . . . . . . . . . .  51
     A.14. 13 to 14  . . . . . . . . . . . . . . . . . . . . . . . .  51
     A.15. 14 to 15  . . . . . . . . . . . . . . . . . . . . . . . .  51
     A.16. 15 to 16  . . . . . . . . . . . . . . . . . . . . . . . .  52
     A.17. 16 to 17  . . . . . . . . . . . . . . . . . . . . . . . .  52
     A.18. 17 to 18  . . . . . . . . . . . . . . . . . . . . . . . .  52
     A.19. 18 to 19  . . . . . . . . . . . . . . . . . . . . . . . .  53
     A.20. 19 to 20  . . . . . . . . . . . . . . . . . . . . . . . .  53
     A.21. 20 to 21  . . . . . . . . . . . . . . . . . . . . . . . .  53
     A.22. 21 to 22  . . . . . . . . . . . . . . . . . . . . . . . .  53
     A.23. 22 to 23  . . . . . . . . . . . . . . . . . . . . . . . .  53
     A.24. 23 to 24  . . . . . . . . . . . . . . . . . . . . . . . .  53
     A.25. 24 to 25  . . . . . . . . . . . . . . . . . . . . . . . .  54
     A.26. 25 to 26  . . . . . . . . . . . . . . . . . . . . . . . .  54

Watsen                  Expires 17 September 2024               [Page 3]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

     A.27. 26 to 27  . . . . . . . . . . . . . . . . . . . . . . . .  54
     A.28. 27 to 28  . . . . . . . . . . . . . . . . . . . . . . . .  54
     A.29. 28 to 29  . . . . . . . . . . . . . . . . . . . . . . . .  54
     A.30. 29 to 30  . . . . . . . . . . . . . . . . . . . . . . . .  55
     A.31. 30 to 31  . . . . . . . . . . . . . . . . . . . . . . . .  55
     A.32. 31 to 33  . . . . . . . . . . . . . . . . . . . . . . . .  55
     A.33. 33 to 34  . . . . . . . . . . . . . . . . . . . . . . . .  55
     A.34. 34 to 35  . . . . . . . . . . . . . . . . . . . . . . . .  55
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  55
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  55

1.  Introduction

   This document presents a YANG 1.1 [RFC7950] module called "ietf-
   keystore" that enables centralized configuration of both symmetric
   and asymmetric keys.  The secret value for both key types may be
   encrypted or hidden (see [I-D.ietf-netconf-crypto-types]).
   Asymmetric keys may be associated with certificates.  Notifications
   are sent when certificates are about to expire.

   The "ietf-keystore" module defines many "grouping" statements
   intended for use by other modules that may import it.  For instance,
   there are groupings that define enabling a key to be either
   configured inline (within the defining data model) or as a reference
   to a key in the central keystore.

   Special consideration has been given for servers that have
   cryptographic hardware, such as a Trusted Platform Module (TPM).
   These servers are unique in that the cryptographic hardware hides the
   secret key values.  Additionally, such hardware is commonly
   initialized when manufactured to protect a "built-in" asymmetric key
   for which its public half is conveyed in an identity certificate
   (e.g., an IDevID [Std-802.1AR-2018] certificate).  Please see
   Section 3 to see how built-in keys are supported.

   This document is intended to reflect existing practices that many
   server implementations support at the time of writing.  To simplify
   implementation, advanced key formats may be selectively implemented.

   Implementations may utilize operating-system level keystore utilities
   (e.g., "Keychain Access" on MacOS) and/or cryptographic hardware
   (e.g., TPMs).

Watsen                  Expires 17 September 2024               [Page 4]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

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, ultimately,
   support the configuration of both the clients and servers of both the
   NETCONF [RFC6241] and RESTCONF [RFC8040] protocols.

   The dependency relationship between the primary YANG groupings
   defined in the various RFCs is presented in the below diagram.  In
   some cases, a draft may define secondary groupings that introduce
   dependencies not illustrated in the diagram.  The labels in the
   diagram are a shorthand name for the defining RFC.  The citation
   reference for shorthand name is provided below the diagram.

   Please note that the arrows in the diagram point from referencer to
   referenced.  For example, the "crypto-types" RFC does not have any
   dependencies, whilst the "keystore" RFC depends on the "crypto-types"
   RFC.

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

Watsen                  Expires 17 September 2024               [Page 5]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   +======================+===========================================+
   |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 in Diagram to RFC Mapping

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.  Terminology

   The terms "client" and "server" are defined in [RFC6241] and are not
   redefined here.

   The term "keystore" is defined in this document as a mechanism that
   intends to safeguard secrets.

   The nomenclature "<running>" and "<operational>" are defined in
   [RFC8342].

   The sentence fragments "augmented" and "augmented in" are used herein
   as the past tense verbified form of the "augment" statement defined
   in Section 7.17 of [RFC7950].

Watsen                  Expires 17 September 2024               [Page 6]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   The term "key" may be used to mean one of three things in this
   document: 1) the YANG-defined "asymmetric-key" or "symmetric-key"
   node defined in this document, 2) the raw key data possessed by the
   aforementioned key nodes, and 3) the "key" of a YANG "list"
   statement.  This document attempts to always qualify types '2' and
   '3' using, "raw key value" and "YANG list key" where needed.  In all
   other cases, an unqualified "key" refers to a YANG-defined
   "asymmetric-key" or "symmetric-key" node.

1.4.  Adherence to the NMDA

   This document is compliant with Network Management Datastore
   Architecture (NMDA) [RFC8342].  For instance, keys and associated
   certificates installed during manufacturing (e.g., for an IDevID
   certificate) are expected to appear in <operational> (see Section 3).

1.5.  Conventions

   Various examples in this document use "BASE64VALUE=" as a placeholder
   value for binary data that has been base64 encoded (per Section 9.8
   of [RFC7950]).  This placeholder value is used because real base64
   encoded structures are often many lines long and hence distracting to
   the example being presented.

   This document uses the adjective "central" to the word "keystore" to
   refer to the top-level instance of the "keystore-grouping", when the
   "central-keystore-supported" feature is enabled.  Please be aware
   that consuming YANG modules MAY instantiate the "keystore-grouping"
   in other locations.  All such other instances are not the "central"
   instance.

2.  The "ietf-keystore" Module

   This section defines a YANG 1.1 [RFC7950] module called "ietf-
   keystore".  A high-level overview of the module is provided in
   Section 2.1.  Examples illustrating the module's use are provided in
   Section 2.2.  The YANG module itself is defined in Section 2.3.

2.1.  Data Model Overview

   This section provides an overview of the "ietf-keystore" module in
   terms of its features, typedefs, groupings, and protocol-accessible
   nodes.

2.1.1.  Features

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

Watsen                  Expires 17 September 2024               [Page 7]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   Features:
     +-- central-keystore-supported
     +-- inline-definitions-supported
     +-- asymmetric-keys
     +-- symmetric-keys

   The diagram above uses syntax that is similar to but not defined in
   [RFC8340].

2.1.2.  Typedefs

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

   Typedefs:
     leafref
       +-- central-symmetric-key-ref
       +-- central-asymmetric-key-ref

   The diagram above uses syntax that is similar to but not defined in
   [RFC8340].

   Comments:

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

   *  The leafrefs refer to symmetric and asymmetric keys in the central
      keystore, when this module is implemented.

   *  These typedefs are provided as an aid to consuming modules that
      import the "ietf-keystore" module.

2.1.3.  Groupings

   The "ietf-keystore" module defines the following "grouping"
   statements:

   *  encrypted-by-grouping
   *  central-asymmetric-key-certificate-ref-grouping
   *  inline-or-keystore-symmetric-key-grouping
   *  inline-or-keystore-asymmetric-key-grouping
   *  inline-or-keystore-asymmetric-key-with-certs-grouping
   *  inline-or-keystore-end-entity-cert-with-key-grouping
   *  keystore-grouping

   Each of these groupings are presented in the following subsections.

Watsen                  Expires 17 September 2024               [Page 8]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

2.1.3.1.  The "encrypted-by-grouping" Grouping

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

     grouping encrypted-by-grouping:
       +-- (encrypted-by)
          +--:(central-symmetric-key-ref)
          |        {central-keystore-supported,symmetric-keys}?
          |  +-- symmetric-key-ref?    ks:central-symmetric-key-ref
          +--:(central-asymmetric-key-ref)
                   {central-keystore-supported,asymmetric-keys}?
             +-- asymmetric-key-ref?   ks:central-asymmetric-key-ref

   Comments:

   *  This grouping defines a "choice" statement with options to
      reference either a symmetric or an asymmetric key configured in
      the keystore.

   *  This grouping is usable only when the keystore module is
      implemented.  Servers defining custom keystore locations MUST
      augment in alternate "encrypted-by" references to the alternate
      locations.

2.1.3.2.  The "central-asymmetric-key-certificate-ref-grouping" Grouping

   The following tree diagram [RFC8340] illustrates the "central-
   asymmetric-key-certificate-ref-grouping" grouping:

     grouping central-asymmetric-key-certificate-ref-grouping:
       +-- asymmetric-key?   ks:central-asymmetric-key-ref
       |       {central-keystore-supported,asymmetric-keys}?
       +-- certificate?      leafref

   Comments:

   *  This grouping defines a reference to a certificate in two parts:
      the first being the name of the asymmetric key the certificate is
      associated with, and the second being the name of the certificate
      itself.

   *  This grouping is usable only when the keystore module is
      implemented.  Servers defining custom keystore locations can
      define an alternate grouping for references to the alternate
      locations.

Watsen                  Expires 17 September 2024               [Page 9]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

2.1.3.3.  The "inline-or-keystore-symmetric-key-grouping" Grouping

   The following tree diagram [RFC8340] illustrates the "inline-or-
   keystore-symmetric-key-grouping" grouping:

     grouping inline-or-keystore-symmetric-key-grouping:
       +-- (inline-or-keystore)
          +--:(inline) {inline-definitions-supported}?
          |  +-- inline-definition
          |     +---u ct:symmetric-key-grouping
          +--:(central-keystore)
                   {central-keystore-supported,symmetric-keys}?
             +-- central-keystore-reference?
                     ks:central-symmetric-key-ref

   Comments:

   *  The "inline-or-keystore-symmetric-key-grouping" grouping is
      provided solely as convenience to consuming modules that wish to
      offer an option for whether a symmetric key is defined inline or
      as a reference to a symmetric key in the keystore.

   *  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 symmetric key in an alternate location.

   *  For the "inline-definition" option, the definition uses the
      "symmetric-key-grouping" grouping discussed in Section 2.1.4.3 of
      [I-D.ietf-netconf-crypto-types].

   *  For the "central-keystore" option, the "central-keystore-
      reference" is an instance of the "symmetric-key-ref" discussed in
      Section 2.1.2.

2.1.3.4.  The "inline-or-keystore-asymmetric-key-grouping" Grouping

   The following tree diagram [RFC8340] illustrates the "inline-or-
   keystore-asymmetric-key-grouping" grouping:

Watsen                  Expires 17 September 2024              [Page 10]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

     grouping inline-or-keystore-asymmetric-key-grouping:
       +-- (inline-or-keystore)
          +--:(inline) {inline-definitions-supported}?
          |  +-- inline-definition
          |     +---u ct:asymmetric-key-pair-grouping
          +--:(central-keystore)
                   {central-keystore-supported,asymmetric-keys}?
             +-- central-keystore-reference?
                     ks:central-asymmetric-key-ref

   Comments:

   *  The "inline-or-keystore-asymmetric-key-grouping" grouping is
      provided solely as convenience to consuming modules that wish to
      offer an option for whether an asymmetric key is defined inline or
      as a reference to an asymmetric key in the keystore.

   *  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 an asymmetric key in an alternate location.

   *  For the "inline-definition" option, the definition uses the
      "asymmetric-key-pair-grouping" grouping discussed in
      Section 2.1.4.6 of [I-D.ietf-netconf-crypto-types].

   *  For the "central-keystore" option, the "central-keystore-
      reference" is an instance of the "asymmetric-key-ref" typedef
      discussed in Section 2.1.2.

2.1.3.5.  The "inline-or-keystore-asymmetric-key-with-certs-grouping"
          Grouping

   The following tree diagram [RFC8340] illustrates the "inline-or-
   keystore-asymmetric-key-with-certs-grouping" grouping:

     grouping inline-or-keystore-asymmetric-key-with-certs-grouping:
       +-- (inline-or-keystore)
          +--:(inline) {inline-definitions-supported}?
          |  +-- inline-definition
          |     +---u ct:asymmetric-key-pair-with-certs-grouping
          +--:(central-keystore)
                   {central-keystore-supported,asymmetric-keys}?
             +-- central-keystore-reference?
                     ks:central-asymmetric-key-ref

   Comments:

Watsen                  Expires 17 September 2024              [Page 11]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   *  The "inline-or-keystore-asymmetric-key-with-certs-grouping"
      grouping is provided solely as convenience to consuming modules
      that wish to offer an option for whether an asymmetric key is
      defined inline or as a reference to an asymmetric key in the
      keystore.

   *  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 an asymmetric key in an alternate location.

   *  For the "inline-definition" option, the definition uses the
      "asymmetric-key-pair-with-certs-grouping" grouping discussed in
      Section 2.1.4.12 of [I-D.ietf-netconf-crypto-types].

   *  For the "central-keystore" option, the "central-keystore-
      reference" is an instance of the "asymmetric-key-ref" typedef
      discussed in Section 2.1.2.

2.1.3.6.  The "inline-or-keystore-end-entity-cert-with-key-grouping"
          Grouping

   The following tree diagram [RFC8340] illustrates the "inline-or-
   keystore-end-entity-cert-with-key-grouping" grouping:

     grouping inline-or-keystore-end-entity-cert-with-key-grouping:
       +-- (inline-or-keystore)
          +--:(inline) {inline-definitions-supported}?
          |  +-- inline-definition
          |     +---u ct:asymmetric-key-pair-with-cert-grouping
          +--:(central-keystore)
                   {central-keystore-supported,asymmetric-keys}?
             +-- central-keystore-reference
                +---u central-asymmetric-key-certificate-ref-grouping

   Comments:

   *  The "inline-or-keystore-end-entity-cert-with-key-grouping"
      grouping is provided solely as convenience to consuming modules
      that wish to offer an option for whether a symmetric key is
      defined inline or as a reference to a symmetric key in the
      keystore.

   *  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 symmetric key in an alternate location.

Watsen                  Expires 17 September 2024              [Page 12]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   *  For the "inline-definition" option, the definition uses the
      "asymmetric-key-pair-with-certs-grouping" grouping discussed in
      Section 2.1.4.12 of [I-D.ietf-netconf-crypto-types].

   *  For the "central-keystore" option, the "central-keystore-
      reference" uses the "central-asymmetric-key-certificate-ref-
      grouping" grouping discussed in Section 2.1.3.2.

2.1.3.7.  The "keystore-grouping" Grouping

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

     grouping keystore-grouping:
       +-- asymmetric-keys {asymmetric-keys}?
       |  +-- asymmetric-key* [name]
       |     +-- name?                                         string
       |     +---u ct:asymmetric-key-pair-with-certs-grouping
       +-- symmetric-keys {symmetric-keys}?
          +-- symmetric-key* [name]
             +-- name?                        string
             +---u ct:symmetric-key-grouping

   Comments:

   *  The "keystore-grouping" grouping defines a keystore instance as
      being composed of symmetric and asymmetric keys.  The structure
      for the symmetric and asymmetric keys is essentially the same,
      being a "list" inside a "container".

   *  For asymmetric keys, each "asymmetric-key" uses the "asymmetric-
      key-pair-with-certs-grouping" grouping discussed in
      Section 2.1.4.12 of [I-D.ietf-netconf-crypto-types].

   *  For symmetric keys, each "symmetric-key" uses the "symmetric-key-
      grouping" grouping discussed in Section 2.1.4.3 of
      [I-D.ietf-netconf-crypto-types].

2.1.4.  Protocol-accessible Nodes

   The following tree diagram [RFC8340] lists all the protocol-
   accessible nodes defined in the "ietf-keystore" module, without
   expanding the "grouping" statements:

   module: ietf-keystore
     +--rw keystore {central-keystore-supported}?
        +---u keystore-grouping

Watsen                  Expires 17 September 2024              [Page 13]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   The following tree diagram [RFC8340] lists all the protocol-
   accessible nodes defined in the "ietf-keystore" module, with all
   "grouping" statements expanded, enabling the keystore's full
   structure to be seen:

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

   module: ietf-keystore
     +--rw keystore {central-keystore-supported}?
        +--rw asymmetric-keys {asymmetric-keys}?
        |  +--rw asymmetric-key* [name]
        |     +--rw name                           string
        |     +--rw public-key-format?             identityref
        |     +--rw public-key?                    binary
        |     +--rw private-key-format?            identityref
        |     +--rw (private-key-type)
        |     |  +--:(cleartext-private-key) {cleartext-private-keys}?
        |     |  |  +--rw cleartext-private-key?   binary
        |     |  +--:(hidden-private-key) {hidden-private-keys}?
        |     |  |  +--rw hidden-private-key?      empty
        |     |  +--:(encrypted-private-key) {encrypted-private-keys}?
        |     |     +--rw encrypted-private-key
        |     |        +--rw encrypted-by
        |     |        |  +--rw (encrypted-by)
        |     |        |     +--:(central-symmetric-key-ref)
        |     |        |     |        {central-keystore-supported,symme\
   tric-keys}?
        |     |        |     |  +--rw symmetric-key-ref?
        |     |        |     |          ks:central-symmetric-key-ref
        |     |        |     +--:(central-asymmetric-key-ref)
        |     |        |              {central-keystore-supported,asymm\
   etric-keys}?
        |     |        |        +--rw asymmetric-key-ref?
        |     |        |                ks:central-asymmetric-key-ref
        |     |        +--rw encrypted-value-format    identityref
        |     |        +--rw encrypted-value           binary
        |     +--rw certificates
        |     |  +--rw certificate* [name]
        |     |     +--rw name                      string
        |     |     +--rw cert-data                 end-entity-cert-cms
        |     |     +---n certificate-expiration
        |     |             {certificate-expiration-notification}?
        |     |        +-- expiration-date    yang:date-and-time
        |     +---x generate-csr {csr-generation}?
        |        +---w input
        |        |  +---w csr-format    identityref
        |        |  +---w csr-info      csr-info
        |        +--ro output

Watsen                  Expires 17 September 2024              [Page 14]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

        |           +--ro (csr-type)
        |              +--:(p10-csr)
        |                 +--ro p10-csr?   p10-csr
        +--rw symmetric-keys {symmetric-keys}?
           +--rw symmetric-key* [name]
              +--rw name                             string
              +--rw key-format?                      identityref
              +--rw (key-type)
                 +--:(cleartext-symmetric-key)
                 |  +--rw cleartext-symmetric-key?   binary
                 |          {cleartext-symmetric-keys}?
                 +--:(hidden-symmetric-key) {hidden-symmetric-keys}?
                 |  +--rw hidden-symmetric-key?      empty
                 +--:(encrypted-symmetric-key)
                          {encrypted-symmetric-keys}?
                    +--rw encrypted-symmetric-key
                       +--rw encrypted-by
                       |  +--rw (encrypted-by)
                       |     +--:(central-symmetric-key-ref)
                       |     |        {central-keystore-supported,symme\
   tric-keys}?
                       |     |  +--rw symmetric-key-ref?
                       |     |          ks:central-symmetric-key-ref
                       |     +--:(central-asymmetric-key-ref)
                       |              {central-keystore-supported,asymm\
   etric-keys}?
                       |        +--rw asymmetric-key-ref?
                       |                ks:central-asymmetric-key-ref
                       +--rw encrypted-value-format    identityref
                       +--rw encrypted-value           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].

   *  The protocol-accessible nodes for the "ietf-keystore" module are
      instances of the "keystore-grouping" grouping discussed in
      Section 2.1.3.7.

   *  The top-level node "keystore" is additionally constrained by the
      feature "central-keystore-supported".

   *  The "keystore-grouping" grouping is discussed in Section 2.1.3.7.

Watsen                  Expires 17 September 2024              [Page 15]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   *  The reason for why "keystore-grouping" exists separate from the
      protocol-accessible nodes definition is so as to enable instances
      of the keystore 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 Keystore Instance

   The following example illustrates keys in <running>.  Please see
   Section 3 for an example illustrating built-in values in
   <operational>.

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

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

      <symmetric-keys>
         <symmetric-key>
            <name>cleartext-symmetric-key</name>
            <key-format>ct:octet-string-key-format</key-format>
            <cleartext-symmetric-key>BASE64VALUE=</cleartext-symmetric-\
   key>
         </symmetric-key>
         <symmetric-key>
            <name>hidden-symmetric-key</name>
            <hidden-symmetric-key/>
         </symmetric-key>
         <symmetric-key>
            <name>encrypted-symmetric-key</name>
            <key-format>ct:one-symmetric-key-format</key-format>
            <encrypted-symmetric-key>
              <encrypted-by>
                <asymmetric-key-ref>hidden-asymmetric-key</asymmetric-k\
   ey-ref>
              </encrypted-by>
              <encrypted-value-format>ct:cms-enveloped-data-format</enc\
   rypted-value-format>
              <encrypted-value>BASE64VALUE=</encrypted-value>
            </encrypted-symmetric-key>
         </symmetric-key>
      </symmetric-keys>

Watsen                  Expires 17 September 2024              [Page 16]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

      <asymmetric-keys>
         <asymmetric-key>
            <name>ssh-rsa-key</name>
            <private-key-format>ct:rsa-private-key-format</private-key-\
   format>
            <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
         </asymmetric-key>
         <asymmetric-key>
            <name>ssh-rsa-key-with-cert</name>
            <private-key-format>ct:rsa-private-key-format</private-key-\
   format>
            <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
            <certificates>
               <certificate>
                  <name>ex-rsa-cert2</name>
                  <cert-data>BASE64VALUE=</cert-data>
               </certificate>
            </certificates>
         </asymmetric-key>
         <asymmetric-key>
            <name>raw-private-key</name>
            <private-key-format>ct:rsa-private-key-format</private-key-\
   format>
            <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
         </asymmetric-key>
         <asymmetric-key>
            <name>rsa-asymmetric-key</name>
            <private-key-format>ct:rsa-private-key-format</private-key-\
   format>
            <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
            <certificates>
               <certificate>
                  <name>ex-rsa-cert</name>
                  <cert-data>BASE64VALUE=</cert-data>
               </certificate>
            </certificates>
         </asymmetric-key>
         <asymmetric-key>
            <name>ec-asymmetric-key</name>
            <private-key-format>ct:ec-private-key-format</private-key-f\
   ormat>
            <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
            <certificates>
               <certificate>
                  <name>ex-ec-cert</name>
                  <cert-data>BASE64VALUE=</cert-data>
               </certificate>
            </certificates>

Watsen                  Expires 17 September 2024              [Page 17]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

         </asymmetric-key>
         <asymmetric-key>
            <name>hidden-asymmetric-key</name>
            <public-key-format>ct:subject-public-key-info-format</publi\
   c-key-format>
            <public-key>BASE64VALUE=</public-key>
            <hidden-private-key/>
            <certificates>
               <certificate>
                  <name>builtin-idevid-cert</name>
                  <cert-data>BASE64VALUE=</cert-data>
               </certificate>
               <certificate>
                  <name>my-ldevid-cert</name>
                  <cert-data>BASE64VALUE=</cert-data>
               </certificate>
            </certificates>
         </asymmetric-key>
         <asymmetric-key>
            <name>encrypted-asymmetric-key</name>
            <private-key-format>ct:one-asymmetric-key-format</private-k\
   ey-format>
            <encrypted-private-key>
              <encrypted-by>
                <symmetric-key-ref>encrypted-symmetric-key</symmetric-k\
   ey-ref>
              </encrypted-by>
              <encrypted-value-format>ct:cms-encrypted-data-format</enc\
   rypted-value-format>
              <encrypted-value>BASE64VALUE=</encrypted-value>
            </encrypted-private-key>
         </asymmetric-key>
      </asymmetric-keys>
   </keystore>

2.2.2.  A Certificate Expiration Notification

   The following example illustrates a "certificate-expiration"
   notification for a certificate associated with an asymmetric key
   configured in the keystore.

Watsen                  Expires 17 September 2024              [Page 18]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

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

   <notification
     xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
     <eventTime>2018-05-25T00:01:00Z</eventTime>
     <keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore">
       <asymmetric-keys>
         <asymmetric-key>
           <name>hidden-asymmetric-key</name>
           <certificates>
             <certificate>
               <name>my-ldevid-cert</name>
               <certificate-expiration>
                 <expiration-date>2018-08-05T14:18:53-05:00</expiration\
   -date>
               </certificate-expiration>
             </certificate>
           </certificates>
         </asymmetric-key>
       </asymmetric-keys>
     </keystore>
   </notification>

2.2.3.  The "Local or Keystore" Groupings

   This section illustrates the various "inline-or-keystore" groupings
   defined in the "ietf-keystore" module, specifically the "inline-or-
   keystore-symmetric-key-grouping" (Section 2.1.3.3), "inline-or-
   keystore-asymmetric-key-grouping" (Section 2.1.3.4), "inline-or-
   keystore-asymmetric-key-with-certs-grouping" (Section 2.1.3.5), and
   "inline-or-keystore-end-entity-cert-with-key-grouping"
   (Section 2.1.3.6) groupings.

   These examples assume the existence of an example module called "ex-
   keystore-usage" having the namespace "https://example.com/ns/example-
   keystore-usage".

   The ex-keystore-usage module is first presented using tree diagrams
   [RFC8340], followed by an instance example illustrating all the
   "inline-or-keystore" groupings in use, followed by the YANG module
   itself.

2.2.3.1.  Tree Diagrams for the "ex-keystore-usage" Module

   The following tree diagram illustrates "ex-keystore-usage" without
   expanding the "grouping" statements:

Watsen                  Expires 17 September 2024              [Page 19]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

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

   module: ex-keystore-usage
     +--rw keystore-usage
        +--rw symmetric-key* [name]
        |  +--rw name                                            string
        |  +---u ks:inline-or-keystore-symmetric-key-grouping
        +--rw asymmetric-key* [name]
        |  +--rw name                                             string
        |  +---u ks:inline-or-keystore-asymmetric-key-grouping
        +--rw asymmetric-key-with-certs* [name]
        |  +--rw name
        |  |       string
        |  +---u ks:inline-or-keystore-asymmetric-key-with-certs-groupi\
   ng
        +--rw end-entity-cert-with-key* [name]
           +--rw name
           |       string
           +---u ks:inline-or-keystore-end-entity-cert-with-key-grouping

   The following tree diagram illustrates the "ex-keystore-usage"
   module, with all "grouping" statements expanded, enabling the usage's
   full structure to be seen:

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

   module: ex-keystore-usage
     +--rw keystore-usage
        +--rw symmetric-key* [name]
        |  +--rw name                                string
        |  +--rw (inline-or-keystore)
        |     +--:(inline) {inline-definitions-supported}?
        |     |  +--rw inline-definition
        |     |     +--rw key-format?                      identityref
        |     |     +--rw (key-type)
        |     |        +--:(cleartext-symmetric-key)
        |     |        |  +--rw cleartext-symmetric-key?   binary
        |     |        |          {cleartext-symmetric-keys}?
        |     |        +--:(hidden-symmetric-key)
        |     |        |        {hidden-symmetric-keys}?
        |     |        |  +--rw hidden-symmetric-key?      empty
        |     |        +--:(encrypted-symmetric-key)
        |     |                 {encrypted-symmetric-keys}?
        |     |           +--rw encrypted-symmetric-key
        |     |              +--rw encrypted-by
        |     |              +--rw encrypted-value-format    identityref
        |     |              +--rw encrypted-value           binary
        |     +--:(central-keystore)

Watsen                  Expires 17 September 2024              [Page 20]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

        |              {central-keystore-supported,symmetric-keys}?
        |        +--rw central-keystore-reference?
        |                ks:central-symmetric-key-ref
        +--rw asymmetric-key* [name]
        |  +--rw name                                string
        |  +--rw (inline-or-keystore)
        |     +--:(inline) {inline-definitions-supported}?
        |     |  +--rw inline-definition
        |     |     +--rw public-key-format?             identityref
        |     |     +--rw public-key?                    binary
        |     |     +--rw private-key-format?            identityref
        |     |     +--rw (private-key-type)
        |     |        +--:(cleartext-private-key)
        |     |        |        {cleartext-private-keys}?
        |     |        |  +--rw cleartext-private-key?   binary
        |     |        +--:(hidden-private-key) {hidden-private-keys}?
        |     |        |  +--rw hidden-private-key?      empty
        |     |        +--:(encrypted-private-key)
        |     |                 {encrypted-private-keys}?
        |     |           +--rw encrypted-private-key
        |     |              +--rw encrypted-by
        |     |              +--rw encrypted-value-format    identityref
        |     |              +--rw encrypted-value           binary
        |     +--:(central-keystore)
        |              {central-keystore-supported,asymmetric-keys}?
        |        +--rw central-keystore-reference?
        |                ks:central-asymmetric-key-ref
        +--rw asymmetric-key-with-certs* [name]
        |  +--rw name                                string
        |  +--rw (inline-or-keystore)
        |     +--:(inline) {inline-definitions-supported}?
        |     |  +--rw inline-definition
        |     |     +--rw public-key-format?             identityref
        |     |     +--rw public-key?                    binary
        |     |     +--rw private-key-format?            identityref
        |     |     +--rw (private-key-type)
        |     |     |  +--:(cleartext-private-key)
        |     |     |  |        {cleartext-private-keys}?
        |     |     |  |  +--rw cleartext-private-key?   binary
        |     |     |  +--:(hidden-private-key) {hidden-private-keys}?
        |     |     |  |  +--rw hidden-private-key?      empty
        |     |     |  +--:(encrypted-private-key)
        |     |     |           {encrypted-private-keys}?
        |     |     |     +--rw encrypted-private-key
        |     |     |        +--rw encrypted-by
        |     |     |        +--rw encrypted-value-format    identityref
        |     |     |        +--rw encrypted-value           binary
        |     |     +--rw certificates

Watsen                  Expires 17 September 2024              [Page 21]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

        |     |     |  +--rw certificate* [name]
        |     |     |     +--rw name                      string
        |     |     |     +--rw cert-data
        |     |     |     |       end-entity-cert-cms
        |     |     |     +---n certificate-expiration
        |     |     |             {certificate-expiration-notification}?
        |     |     |        +-- expiration-date    yang:date-and-time
        |     |     +---x generate-csr {csr-generation}?
        |     |        +---w input
        |     |        |  +---w csr-format    identityref
        |     |        |  +---w csr-info      csr-info
        |     |        +--ro output
        |     |           +--ro (csr-type)
        |     |              +--:(p10-csr)
        |     |                 +--ro p10-csr?   p10-csr
        |     +--:(central-keystore)
        |              {central-keystore-supported,asymmetric-keys}?
        |        +--rw central-keystore-reference?
        |                ks:central-asymmetric-key-ref
        +--rw end-entity-cert-with-key* [name]
           +--rw name                                string
           +--rw (inline-or-keystore)
              +--:(inline) {inline-definitions-supported}?
              |  +--rw inline-definition
              |     +--rw public-key-format?             identityref
              |     +--rw public-key?                    binary
              |     +--rw private-key-format?            identityref
              |     +--rw (private-key-type)
              |     |  +--:(cleartext-private-key)
              |     |  |        {cleartext-private-keys}?
              |     |  |  +--rw cleartext-private-key?   binary
              |     |  +--:(hidden-private-key) {hidden-private-keys}?
              |     |  |  +--rw hidden-private-key?      empty
              |     |  +--:(encrypted-private-key)
              |     |           {encrypted-private-keys}?
              |     |     +--rw encrypted-private-key
              |     |        +--rw encrypted-by
              |     |        +--rw encrypted-value-format    identityref
              |     |        +--rw encrypted-value           binary
              |     +--rw cert-data?
              |     |       end-entity-cert-cms
              |     +---n certificate-expiration
              |     |       {certificate-expiration-notification}?
              |     |  +-- expiration-date    yang:date-and-time
              |     +---x generate-csr {csr-generation}?
              |        +---w input
              |        |  +---w csr-format    identityref
              |        |  +---w csr-info      csr-info

Watsen                  Expires 17 September 2024              [Page 22]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

              |        +--ro output
              |           +--ro (csr-type)
              |              +--:(p10-csr)
              |                 +--ro p10-csr?   p10-csr
              +--:(central-keystore)
                       {central-keystore-supported,asymmetric-keys}?
                 +--rw central-keystore-reference
                    +--rw asymmetric-key?
                    |       ks:central-asymmetric-key-ref
                    |       {central-keystore-supported,asymmetric-keys\
   }?
                    +--rw certificate?      leafref

2.2.3.2.  Example Usage for the "ex-keystore-usage" Module

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

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

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

     <!-- The following two equivalent examples illustrate the -->
     <!-- "inline-or-keystore-symmetric-key-grouping" grouping: -->

     <symmetric-key>
       <name>example 1a</name>
       <central-keystore-reference>cleartext-symmetric-key</central-key\
   store-reference>
     </symmetric-key>

     <symmetric-key>
       <name>example 1b</name>
       <inline-definition>
         <key-format>ct:octet-string-key-format</key-format>
         <cleartext-symmetric-key>BASE64VALUE=</cleartext-symmetric-key>
       </inline-definition>
     </symmetric-key>

     <!-- The following two equivalent examples illustrate the  -->

Watsen                  Expires 17 September 2024              [Page 23]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

     <!-- "inline-or-keystore-asymmetric-key-grouping" grouping: -->

     <asymmetric-key>
       <name>example 2a</name>
       <central-keystore-reference>rsa-asymmetric-key</central-keystore\
   -reference>
     </asymmetric-key>

     <asymmetric-key>
       <name>example 2b</name>
       <inline-definition>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>BASE64VALUE=</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
       </inline-definition>
     </asymmetric-key>

     <!-- the following two equivalent examples illustrate        -->
     <!-- "inline-or-keystore-asymmetric-key-with-certs-grouping": -->

     <asymmetric-key-with-certs>
       <name>example 3a</name>
       <central-keystore-reference>rsa-asymmetric-key</central-keystore\
   -reference>
     </asymmetric-key-with-certs>

     <asymmetric-key-with-certs>
       <name>example 3b</name>
       <inline-definition>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>BASE64VALUE=</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
         <certificates>
           <certificate>
             <name>a locally-defined cert</name>
             <cert-data>BASE64VALUE=</cert-data>
           </certificate>
         </certificates>
       </inline-definition>
     </asymmetric-key-with-certs>

Watsen                  Expires 17 September 2024              [Page 24]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

     <!-- The following two equivalent examples illustrate       -->
     <!-- "inline-or-keystore-end-entity-cert-with-key-grouping": -->

     <end-entity-cert-with-key>
       <name>example 4a</name>
       <central-keystore-reference>
         <asymmetric-key>rsa-asymmetric-key</asymmetric-key>
         <certificate>ex-rsa-cert</certificate>
       </central-keystore-reference>
     </end-entity-cert-with-key>

     <end-entity-cert-with-key>
       <name>example 4b</name>
       <inline-definition>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>BASE64VALUE=</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
         <cert-data>BASE64VALUE=</cert-data>
       </inline-definition>
     </end-entity-cert-with-key>

   </keystore-usage>

2.2.3.3.  The "ex-keystore-usage" YANG Module

   Following is the "ex-keystore-usage" module's YANG definition:

   module ex-keystore-usage {
     yang-version 1.1;
     namespace "https://example.com/ns/example-keystore-usage";
     prefix ex-keystore-usage;

     import ietf-keystore {
       prefix ks;
       reference
         "RFC CCCC: A YANG Data Model for a Keystore";
     }

     organization
       "Example Corporation";

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

     description

Watsen                  Expires 17 September 2024              [Page 25]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

       "This example module illustrates notable groupings defined
        in the 'ietf-keystore' module.";

     revision 2024-03-16 {
       description
         "Initial version";
       reference
         "RFC CCCC: A YANG Data Model for a Keystore";
     }

     container keystore-usage {
       description
         "An illustration of the various keystore groupings.";
       list symmetric-key {
         key "name";
         leaf name {
           type string;
           description
             "An arbitrary name for this key.";
         }
         uses ks:inline-or-keystore-symmetric-key-grouping;
         description
           "An symmetric key that may be configured locally or be a
            reference to a symmetric key in the keystore.";
       }
       list asymmetric-key {
         key "name";
         leaf name {
           type string;
           description
             "An arbitrary name for this key.";
         }
         uses ks:inline-or-keystore-asymmetric-key-grouping;
         description
           "An asymmetric key, with no certs, that may be configured
            locally or be a reference to an asymmetric key in the
            keystore.  The intent is to reference just the asymmetric
            key, not any certificates that may also be associated
            with the asymmetric key.";
       }
       list asymmetric-key-with-certs {
         key "name";
         leaf name {
           type string;
           description
             "An arbitrary name for this key.";
         }
         uses ks:inline-or-keystore-asymmetric-key-with-certs-grouping;

Watsen                  Expires 17 September 2024              [Page 26]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

         description
           "An asymmetric key and its associated certs, that may be
            configured locally or be a reference to an asymmetric key
            (and its associated certs) in the keystore.";
       }
       list end-entity-cert-with-key {
         key "name";
         leaf name {
           type string;
           description
             "An arbitrary name for this key.";
         }
         uses ks:inline-or-keystore-end-entity-cert-with-key-grouping;
         description
           "An end-entity certificate and its associated asymmetric
            key, that may be configured locally or be a reference
            to another certificate (and its associated asymmetric
            key) in the keystore.";
       }
     }
   }

2.3.  YANG Module

   This YANG module has normative references to [RFC8341] and
   [I-D.ietf-netconf-crypto-types].

   <CODE BEGINS> file "ietf-keystore@2024-03-16.yang"

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

     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";

Watsen                  Expires 17 September 2024              [Page 27]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

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

     description
       "This module defines a 'keystore' to centralize management
        of security credentials.

        Copyright (c) 2024 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 Revised
        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 CCCC
        (https://www.rfc-editor.org/info/rfcCCCC); 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 2024-03-16 {
       description
         "Initial version";
       reference
         "RFC CCCC: A YANG Data Model for a Keystore";
     }

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

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

Watsen                  Expires 17 September 2024              [Page 28]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

     feature inline-definitions-supported {
       description
         "The 'inline-definitions-supported' feature indicates that
          the server supports locally-defined keys.";
     }

     feature asymmetric-keys {
       description
         "The 'asymmetric-keys' feature indicates that the server
          implements the /keystore/asymmetric-keys subtree.";

     }

     feature symmetric-keys {
       description
         "The 'symmetric-keys' feature indicates that the server
          implements the /keystore/symmetric-keys subtree.";
     }

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

     typedef central-symmetric-key-ref {
       type leafref {
         path "/ks:keystore/ks:symmetric-keys/ks:symmetric-key"
            + "/ks:name";
       }
       description
         "This typedef enables modules to easily define a reference
          to a symmetric key stored in the central keystore.";
     }

     typedef central-asymmetric-key-ref {
       type leafref {
         path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
            + "/ks:name";
       }
       description
         "This typedef enables modules to easily define a reference
          to an asymmetric key stored in the central keystore.";
     }

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

     grouping encrypted-by-grouping {

Watsen                  Expires 17 September 2024              [Page 29]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

       description
         "A grouping that defines a 'choice' statement that can be
          augmented into the 'encrypted-by' node, present in the
          'symmetric-key-grouping' and 'asymmetric-key-pair-grouping'
          groupings defined in RFC AAAA, enabling references to keys
          in the central keystore.";
       choice encrypted-by {
         nacm:default-deny-write;
         mandatory true;
         description
           "A choice amongst other symmetric or asymmetric keys.";
         case central-symmetric-key-ref {
           if-feature "central-keystore-supported";
           if-feature "symmetric-keys";
           leaf symmetric-key-ref {
             type ks:central-symmetric-key-ref;
             description
               "Identifies the symmetric key used to encrypt the
                associated key.";
           }
         }
         case central-asymmetric-key-ref {
           if-feature "central-keystore-supported";
           if-feature "asymmetric-keys";
           leaf asymmetric-key-ref {
             type ks:central-asymmetric-key-ref;
             description
               "Identifies the asymmetric key whose public key
                encrypted the associated key.";
           }
         }
       }
     }

     // *-ref groupings

     grouping central-asymmetric-key-certificate-ref-grouping {
       description
         "Grouping for the reference to a certificate associated
          with an asymmetric key stored in the central keystore.";
       leaf asymmetric-key {
         nacm:default-deny-write;
         if-feature "central-keystore-supported";
         if-feature "asymmetric-keys";
         type ks:central-asymmetric-key-ref;
         must '../certificate';
         description
           "A reference to an asymmetric key in the keystore.";

Watsen                  Expires 17 September 2024              [Page 30]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

       }
       leaf certificate {
         nacm:default-deny-write;
         type leafref {
           path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
              + "[ks:name = current()/../asymmetric-key]/"
              + "ks:certificates/ks:certificate/ks:name";
         }
         must '../asymmetric-key';
         description
           "A reference to a specific certificate of the
            asymmetric key in the keystore.";
       }
     }

     // inline-or-keystore-* groupings

     grouping inline-or-keystore-symmetric-key-grouping {
       description
         "A grouping for the configuration of a symmetric key.  The
          symmetric key may be defined inline or as a reference to
          a symmetric key stored in the central keystore.

          Servers that wish to define alternate keystore locations
          SHOULD augment in custom 'case' statements enabling
          references to those alternate keystore locations.";
       choice inline-or-keystore {
         nacm:default-deny-write;
         mandatory true;
         description
           "A choice between an inlined definition and a definition
            that exists in the keystore.";
         case inline {
           if-feature "inline-definitions-supported";
           container inline-definition {
             description
               "Container to hold the local key definition.";
             uses ct:symmetric-key-grouping;
           }
         }
         case central-keystore {
           if-feature "central-keystore-supported";
           if-feature "symmetric-keys";
           leaf central-keystore-reference {
             type ks:central-symmetric-key-ref;
             description
               "A reference to an symmetric key that exists in
                the central keystore.";

Watsen                  Expires 17 September 2024              [Page 31]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

           }
         }
       }
     }

     grouping inline-or-keystore-asymmetric-key-grouping {
       description
         "A grouping for the configuration of an asymmetric key. The
          asymmetric key may be defined inline or as a reference to
          an asymmetric key stored in the central keystore.

          Servers that wish to define alternate keystore locations
          SHOULD augment in custom 'case' statements enabling
          references to those alternate keystore locations.";
       choice inline-or-keystore {
         nacm:default-deny-write;
         mandatory true;
         description
           "A choice between an inlined definition and a definition
            that exists in the keystore.";
         case inline {
           if-feature "inline-definitions-supported";
           container inline-definition {
             description
               "Container to hold the local key definition.";
             uses ct:asymmetric-key-pair-grouping;
           }
         }
         case central-keystore {
           if-feature "central-keystore-supported";
           if-feature "asymmetric-keys";
           leaf central-keystore-reference {
             type ks:central-asymmetric-key-ref;
             description
               "A reference to an asymmetric key that exists in
                the central keystore.  The intent is to reference
                just the asymmetric key without any regard for
                any certificates that may be associated with it.";
           }
         }
       }
     }

     grouping inline-or-keystore-asymmetric-key-with-certs-grouping {
       description
         "A grouping for the configuration of an asymmetric key and
          its associated certificates.  The asymmetric key and its
          associated certificates may be defined inline or as a

Watsen                  Expires 17 September 2024              [Page 32]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

          reference to an asymmetric key (and its associated
          certificates) in the central keystore.

          Servers that wish to define alternate keystore locations
          SHOULD augment in custom 'case' statements enabling
          references to those alternate keystore locations.";
       choice inline-or-keystore {
         nacm:default-deny-write;
         mandatory true;
         description
           "A choice between an inlined definition and a definition
            that exists in the keystore.";
         case inline {
           if-feature "inline-definitions-supported";
           container inline-definition {
             description
               "Container to hold the local key definition.";
             uses ct:asymmetric-key-pair-with-certs-grouping;
           }
         }
         case central-keystore {
           if-feature "central-keystore-supported";
           if-feature "asymmetric-keys";
           leaf central-keystore-reference {
             type ks:central-asymmetric-key-ref;
             description
               "A reference to an asymmetric-key (and all of its
                associated certificates) in the keystore, when
                this module is implemented.";
           }
         }
       }
     }

     grouping inline-or-keystore-end-entity-cert-with-key-grouping {
       description
         "A grouping for the configuration of an asymmetric key and
          its associated end-entity certificate.  The asymmetric key
          and its associated end-entity certificate may be defined
          inline or as a reference to an asymmetric key (and its
          associated end-entity certificate) in the central keystore.

          Servers that wish to define alternate keystore locations
          SHOULD augment in custom 'case' statements enabling
          references to those alternate keystore locations.";
       choice inline-or-keystore {
         nacm:default-deny-write;
         mandatory true;

Watsen                  Expires 17 September 2024              [Page 33]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

         description
           "A choice between an inlined definition and a definition
            that exists in the keystore.";
         case inline {
           if-feature "inline-definitions-supported";
           container inline-definition {
             description
               "Container to hold the local key definition.";
             uses ct:asymmetric-key-pair-with-cert-grouping;
           }
         }
         case central-keystore {
           if-feature "central-keystore-supported";
           if-feature "asymmetric-keys";
           container central-keystore-reference {
             uses central-asymmetric-key-certificate-ref-grouping;
             description
               "A reference to a specific certificate associated with
                an asymmetric key stored in the central keystore.";
           }
         }
       }
     }

     // the keystore grouping

     grouping keystore-grouping {
       description
         "Grouping definition enables use in other contexts.  If ever
          done, implementations MUST augment new 'case' statements
          into the various inline-or-keystore 'choice' statements to
          supply leafrefs to the model-specific location(s).";
       container asymmetric-keys {
         nacm:default-deny-write;
         if-feature "asymmetric-keys";
         description
           "A list of asymmetric keys.";
         list asymmetric-key {
           key "name";
           description
             "An asymmetric key.";
           leaf name {
             type string;
             description
               "An arbitrary name for the asymmetric key.";
           }
           uses ct:asymmetric-key-pair-with-certs-grouping;
         }

Watsen                  Expires 17 September 2024              [Page 34]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

       }
       container symmetric-keys {
         nacm:default-deny-write;
         if-feature "symmetric-keys";
         description
           "A list of symmetric keys.";
         list symmetric-key {
           key "name";
           description
             "A symmetric key.";
           leaf name {
             type string;
             description
               "An arbitrary name for the symmetric key.";
           }
           uses ct:symmetric-key-grouping;
         }
       }
     }

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

     container keystore {
       if-feature central-keystore-supported;
       description
         "A central keystore containing a list of symmetric keys and
          a list of asymmetric keys.";
       nacm:default-deny-write;
       uses keystore-grouping {
         augment "symmetric-keys/symmetric-key/key-type/encrypted-"
               + "symmetric-key/encrypted-symmetric-key/encrypted-by" {
           description
             "Augments in a choice statement enabling the encrypting
              key to be any other symmetric or asymmetric key in the
              central keystore.";
           uses encrypted-by-grouping;
         }
         augment "asymmetric-keys/asymmetric-key/private-key-type/"
               + "encrypted-private-key/encrypted-private-key/"
               + "encrypted-by" {
           description
             "Augments in a choice statement enabling the encrypting
              key to be any other symmetric or asymmetric key in the
              central keystore.";
           uses encrypted-by-grouping;
         }

Watsen                  Expires 17 September 2024              [Page 35]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

       }
     }
   }

   <CODE ENDS>

3.  Support for Built-in Keys

   In some implementations, a server may support keys built into the
   server.  Built-in keys MAY be set during the manufacturing process or
   be dynamically generated the first time the server is booted or a
   particular service (e.g., SSH) is enabled.

   Built-in keys are "hidden" keys expected to be set by a vendor-
   specific process.  Any ability for operators to set and/or modify
   built-in keys is outside the scope of this document.

   The primary characteristic of the built-in keys is that they are
   provided by the server, as opposed to configuration.  As such, they
   are present in <operational> (Section 5.3 of [RFC8342]), and <system>
   [I-D.ietf-netmod-system-config], if implemented.

   The example below illustrates what the keystore in <operational>
   might look like for a server in its factory default state.  Note that
   the built-in keys have the "or:origin" annotation value "or:system".

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

   <keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
     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">
     <asymmetric-keys>
       <asymmetric-key or:origin="or:system">
         <name>Manufacturer-Generated Hidden Key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>BASE64VALUE=</public-key>
         <hidden-private-key/>
         <certificates>
           <certificate>
             <name>Manufacturer-Generated IDevID Cert</name>
             <cert-data>BASE64VALUE=</cert-data>
           </certificate>
         </certificates>
       </asymmetric-key>
     </asymmetric-keys>
   </keystore>

Watsen                  Expires 17 September 2024              [Page 36]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

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

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

   <keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
     <asymmetric-keys>
       <asymmetric-key>
         <name>Manufacturer-Generated Hidden Key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>BASE64VALUE=</public-key>
         <hidden-private-key/>
         <certificates>
           <certificate>
             <name>Manufacturer-Generated IDevID Cert</name>
             <cert-data>BASE64VALUE=</cert-data>
           </certificate>
           <certificate>
             <name>Deployment-Specific LDevID Cert</name>
             <cert-data>BASE64VALUE=</cert-data>
           </certificate>
         </certificates>
       </asymmetric-key>
     </asymmetric-keys>
   </keystore>

   After the above configuration is applied, <operational> should appear
   as follows:

Watsen                  Expires 17 September 2024              [Page 37]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

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

   <keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
     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">
     <asymmetric-keys>
       <asymmetric-key or:origin="or:system">
         <name>Manufacturer-Generated Hidden Key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>BASE64VALUE=</public-key>
         <hidden-private-key/>
         <certificates>
           <certificate>
             <name>Manufacturer-Generated IDevID Cert</name>
             <cert-data>BASE64VALUE=</cert-data>
           </certificate>
           <certificate or:origin="or:intended">
             <name>Deployment-Specific LDevID Cert</name>
             <cert-data>BASE64VALUE=</cert-data>
           </certificate>
         </certificates>
       </asymmetric-key>
     </asymmetric-keys>
   </keystore>

4.  Encrypting Keys in Configuration

   This section describes an approach that enables both the symmetric
   and asymmetric keys on a server to be encrypted, such that
   traditional backup/restore procedures can be used without concern for
   raw key data being compromised when in transit.

   The approach presented in this section is not normative.  This
   section answers how a configuration containing secrets that are
   encrypted by a built-in key (Section 3) can be backup'ed from one
   server and restored on a different server, when each server has
   unique master keys.  The API defined by the "ietf-keystore" YANG
   module presented in this document is sufficient to support the
   workflow described in this section.

Watsen                  Expires 17 September 2024              [Page 38]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

4.1.  Key Encryption Key

   The ability to encrypt configured keys is predicated on the existence
   of a "key encryption key" (KEK).  There may be any number of KEKs in
   a server.  A KEK, by its namesake, is a key that is used to encrypt
   other keys.  A KEK MAY be either a symmetric key or an asymmetric
   key.

   If a KEK is a symmetric key, then the server MUST provide an API for
   administrators to encrypt other keys without needing to know the
   symmetric key's value.  If the KEK is an asymmetric key, then the
   server SHOULD provide an API enabling the encryption of other keys
   or, alternatively, assume the administrators can do so themselves
   using the asymmetric key's public half.

   A server MUST possess access to the KEK, or an API using the KEK, so
   that it can decrypt the other keys in the configuration at runtime.

4.2.  Configuring Encrypted Keys

   Each time a new key is configured, it SHOULD be encrypted by a KEK.

   In "ietf-crypto-types" [I-D.ietf-netconf-crypto-types], the format
   for encrypted values is described by identity statements derived from
   the "symmetrically-encrypted-value-format" and "asymmetrically-
   encrypted-value-format" identity statements.

   Implementations of servers implementing the "ietf-keystore" module
   SHOULD provide an API that simultaneously generates a key and
   encrypts the generated key using a KEK.  Thus the cleartext value of
   the newly generated key may never be known to the administrators
   generating the keys.  Such API is defined in the "ietf-ssh-common"
   and the "ietf-tls-common" YANG modules defined in
   [I-D.ietf-netconf-ssh-client-server], and
   [I-D.ietf-netconf-tls-client-server], respectively.

   In case the server implementation does not provide such an API, then
   the generating and encrypting steps MAY be performed outside the
   server, e.g., by an administrator with special access control rights
   (e.g., an organization's crypto officer).

   In either case, the encrypted key can be configured into the keystore
   using either the "encrypted-symmetric-key" (for symmetric keys) or
   the "encrypted-private-key" (for asymmetric keys) nodes.  These two
   nodes contain both the encrypted raw key value as well as a reference
   to the KEK that encrypted the key.

Watsen                  Expires 17 September 2024              [Page 39]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

4.3.  Migrating Configuration to Another Server

   When a KEK is used to encrypt other keys, migrating the configuration
   to another server is only possible if the second server has the same
   KEK.  How the second server comes to have the same KEK is discussed
   in this section.

   In some deployments, mechanisms outside the scope of this document
   may be used to migrate a KEK from one server to another.  That said,
   beware that the ability to do so typically entails having access to
   the first server but, in some scenarios, the first server may no
   longer be operational.

   In other deployments, an organization's crypto officer, possessing a
   KEK's cleartext value, configures the same KEK on the second server,
   presumably as a hidden key or a key protected by access-control, so
   that the cleartext value is not disclosed to regular administrators.
   However, this approach creates high-coupling to and dependency on the
   crypto officers that does not scale in production environments.

   In order to decouple the crypto officers from the regular
   administrators, a special KEK, called the "master key" (MK), may be
   used.

   A MK is commonly a globally-unique built-in (see Section 3)
   asymmetric key.  The private raw key value, due to its long lifetime,
   is hidden (i.e., "hidden-private-key" in Section 2.1.4.5. of
   [I-D.ietf-netconf-crypto-types]).  The raw public key value is often
   contained in an identity certificate (e.g., IDevID).  How to
   configure a MK during the manufacturing process is outside the scope
   of this document.

   Assuming the server has a MK, the MK can be used to encrypt a "shared
   KEK", which is then used to encrypt the keys configured by regular
   administrators.

   With this extra level of indirection, it is possible for a crypto
   officer to encrypt the same KEK for a multiplicity of servers offline
   using the public key contained in their identity certificates.  The
   crypto officer can then safely handoff the encrypted KEKs to regular
   administrators responsible for server installations, including
   migrations.

   In order to migrate the configuration from a first server, an
   administrator would need to make just a single modification to the
   configuration before loading it onto a second server, which is to
   replace the encrypted KEK keystore entry from the first server with
   the encrypted KEK for the second server.  Upon doing this, the

Watsen                  Expires 17 September 2024              [Page 40]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   configuration (containing many encrypted keys) can be loaded into the
   second server while enabling the second server to decrypt all the
   encrypted keys in the configuration.

   The following diagram illustrates this idea:

Watsen                  Expires 17 September 2024              [Page 41]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

    +-------------+                                 +-------------+
    | shared KEK  |                                 | shared KEK  |
    |(unencrypted)|-------------------------------> | (encrypted) |
    +-------------+     encrypts offline using      +-------------+
           ^            each server's MK                |
           |                                            |
           |                                            |
           |  possesses    \o                           |
           +--------------  |\                          |
                           / \         shares with      |
                         crypto    +--------------------+
                         officer   |
                                   |
                                   |
   +----------------------+        |         +----------------------+
   |       server-1       |        |         |       server-2       |
   |    configuration     |        |         |    configuration     |
   |                      |        |         |                      |
   |                      |        |         |                      |
   |  +----------------+  |        |         |  +----------------+  |
   |  |      MK-1      |  |        |         |  |      MK-2      |  |
   |  |    (hidden)    |  |        |         |  |    (hidden)    |  |
   |  +----------------+  |        |         |  +----------------+  |
   |      ^               |        |         |      ^               |
   |      |               |        |         |      |               |
   |      |               |        |         |      |               |
   |      |  encrypted    |        |         |      |  encrypted    |
   |      |  by           |        |         |      |  by           |
   |      |               |        |         |      |               |
   |      |               |        |         |      |               |
   |  +----------------+  |        |         |  +----------------+  |
   |  |  shared KEK    |  |        |         |  |  shared KEK    |  |
   |  |  (encrypted)   |  |        v         |  |  (encrypted)   |  |
   |  +----------------+  |                  |  +----------------+  |
   |      ^               |     regular      |      ^               |
   |      |               |      admin       |      |               |
   |      |               |                  |      |               |
   |      |  encrypted    |       \o         |      |  encrypted    |
   |      |  by           |        |\        |      |  by           |
   |      |               |       / \        |      |               |
   |      |               |                  |      |               |
   |  +----------------+  |----------------->|  +----------------+  |
   |  | all other keys |  |     migrate      |  | all other keys |  |
   |  |  (encrypted)   |  |  configuration   |  |  (encrypted)   |  |
   |  +----------------+  |                  |  +----------------+  |
   |                      |                  |                      |
   +----------------------+                  +----------------------+

Watsen                  Expires 17 September 2024              [Page 42]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

5.  Security Considerations

5.1.  Security of Data at Rest and in Motion

   The YANG module defined in this document defines a mechanism called a
   "keystore" that intends to protect its contents from unauthorized
   disclosure and modification.

   In order to satisfy the expectations of a "keystore", it is
   RECOMMENDED that server implementations ensure that the keystore
   contents are encrypted when persisted to non-volatile memory, and
   ensure that the keystore contents that have been decrypted in
   volatile memory are zeroized when not in use.

   The keystore contents may be encrypted either by encrypting the
   contents individually (e.g., using the "encrypted" value formats) or,
   in case cleartext values are used (which is NOT RECOMMENDED per
   Section 3.5 of [I-D.ietf-netconf-crypto-types]), then, e.g., disk-
   level encryption may be used.

   If the keystore contents are not encrypted when persisted, then
   server implementations MUST ensure the persisted storage is
   inaccessible.

5.2.  Unconstrained Private Key Usage

   This module enables the configuration of private keys without
   constraints on their usage, e.g., what operations the key is allowed
   to be used for (e.g., signature, decryption, both).

   This module also does not constrain the usage of the associated
   public keys, other than in the context of a configured certificate
   (e.g., an identity certificate), in which case the key usage is
   constrained by the certificate.

5.3.  Considerations for the "ietf-keystore" YANG Module

   This section follows the template defined in Section 3.7.1 of
   [RFC8407].

   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.

Watsen                  Expires 17 September 2024              [Page 43]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   The Network 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.

   Please be aware that this YANG module uses groupings from other YANG
   modules that define nodes that may be considered sensitive or
   vulnerable in network environments.  Please review the Security
   Considerations for dependent YANG modules for information as to which
   nodes may be considered sensitive or vulnerable in network
   environments.

   Some of the readable data nodes defined in this YANG module may be
   considered sensitive or vulnerable in some network environments.  It
   is thus important to control read access (e.g., via get, get-config,
   or notification) to these data nodes.  The following subtrees and
   data nodes have particular sensitivity/vulnerability:

   *  The "cleartext-symmetric-key" node:

         The "cleartext-symmetric-key" node, imported from the
         "symmetric-key-grouping" grouping defined in
         [I-D.ietf-netconf-crypto-types] is additionally sensitive to
         read operations such that, in normal use cases, it should never
         be returned to a client.  For this reason, the NACM extension
         "default-deny-all" was applied to it in
         [I-D.ietf-netconf-crypto-types].

   *  The "cleartext-private-key" node:

         The "cleartext-private-key" node defined in the "asymmetric-
         key-pair-grouping" grouping defined in
         [I-D.ietf-netconf-crypto-types] is additionally sensitive to
         read operations such that, in normal use cases, it should never
         be returned to a client.  For this reason, the NACM extension
         "default-deny-all" is applied to it in
         [I-D.ietf-netconf-crypto-types].

   All the writable data nodes defined by this module, both in the
   "grouping" statements as well as the protocol-accessible "keystore"
   instance, may be considered sensitive or vulnerable in some network
   environments.  For instance, any modification to a key or reference
   to a key 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 "rpc" or "action" statements, and
   thus the security considerations for such is not provided here.

Watsen                  Expires 17 September 2024              [Page 44]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   Built-in key types SHOULD be either hidden and/or encrypted (not
   cleartext).  If this is not possible, access control mechanisms like
   NACM SHOULD be used to limit access to the key's secret data to only
   the most trusted authorized clients (e.g., belonging to an
   organization’s crypto officer).

6.  IANA Considerations

6.1.  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-keystore
      Registrant Contact: The IESG
      XML: N/A, the requested URI is an XML namespace.

6.2.  The "YANG Module Names" Registry

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

      name:         ietf-keystore
      namespace:    urn:ietf:params:xml:ns:yang:ietf-keystore
      prefix:       ks
      reference:    RFC CCCC

7.  References

7.1.  Normative References

   [I-D.ietf-netconf-crypto-types]
              Watsen, K., "YANG Data Types and Groupings for
              Cryptography", Work in Progress, Internet-Draft, draft-
              ietf-netconf-crypto-types-33, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              crypto-types-33>.

   [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>.

Watsen                  Expires 17 September 2024              [Page 45]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   [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>.

   [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>.

   [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>.

7.2.  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-19, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              http-client-server-19>.

   [I-D.ietf-netconf-keystore]
              Watsen, K., "A YANG Data Model for a Keystore and Keystore
              Operations", Work in Progress, Internet-Draft, draft-ietf-
              netconf-keystore-34, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              keystore-34>.

   [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-35, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              netconf-client-server-35>.

   [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-35, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              restconf-client-server-35>.

Watsen                  Expires 17 September 2024              [Page 46]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   [I-D.ietf-netconf-ssh-client-server]
              Watsen, K., "YANG Groupings for SSH Clients and SSH
              Servers", Work in Progress, Internet-Draft, draft-ietf-
              netconf-ssh-client-server-39, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              ssh-client-server-39>.

   [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-23, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              tcp-client-server-23>.

   [I-D.ietf-netconf-tls-client-server]
              Watsen, K., "YANG Groupings for TLS Clients and TLS
              Servers", Work in Progress, Internet-Draft, draft-ietf-
              netconf-tls-client-server-40, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              tls-client-server-40>.

   [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-27, 1 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              trust-anchors-27>.

   [I-D.ietf-netmod-system-config]
              Ma, Q., Wu, Q., and C. Feng, "System-defined
              Configuration", Work in Progress, Internet-Draft, draft-
              ietf-netmod-system-config-05, 21 February 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              system-config-05>.

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

   [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>.

Watsen                  Expires 17 September 2024              [Page 47]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   [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>.

   [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>.

   [RFC8407]  Bierman, A., "Guidelines for Authors and Reviewers of
              Documents Containing YANG Data Models", BCP 216, RFC 8407,
              DOI 10.17487/RFC8407, October 2018,
              <https://www.rfc-editor.org/info/rfc8407>.

   [Std-802.1AR-2018]
              IEEE SA-Standards Board, "IEEE Standard for Local and
              metropolitan area networks - Secure Device Identity",
              August 2018,
              <https://standards.ieee.org/standard/802_1AR-2018.html>.

Appendix A.  Change Log

A.1.  00 to 01

   *  Replaced the 'certificate-chain' structures with PKCS#7
      structures.  (Issue #1)

   *  Added 'private-key' as a configurable data node, and removed the
      'generate-private-key' and 'load-private-key' actions.  (Issue #2)

   *  Moved 'user-auth-credentials' to the ietf-ssh-client module.
      (Issues #4 and #5)

A.2.  01 to 02

   *  Added back 'generate-private-key' action.

   *  Removed 'RESTRICTED' enum from the 'private-key' leaf type.

   *  Fixed up a few description statements.

Watsen                  Expires 17 September 2024              [Page 48]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

A.3.  02 to 03

   *  Changed draft's title.

   *  Added missing references.

   *  Collapsed sections and levels.

   *  Added RFC 8174 to Requirements Language Section.

   *  Renamed 'trusted-certificates' to 'pinned-certificates'.

   *  Changed 'public-key' from config false to config true.

   *  Switched 'host-key' from OneAsymmetricKey to definition from RFC
      4253.

A.4.  03 to 04

   *  Added typedefs around leafrefs to common keystore paths

   *  Now tree diagrams reference ietf-netmod-yang-tree-diagrams

   *  Removed Design Considerations section

   *  Moved key and certificate definitions from data tree to groupings

A.5.  04 to 05

   *  Removed trust anchors (now in their own draft)

   *  Added back global keystore structure

   *  Added groupings enabling keys to either be locally defined or a
      reference to the keystore.

A.6.  05 to 06

   *  Added feature "local-keys-supported"

   *  Added nacm:default-deny-all and nacm:default-deny-write

   *  Renamed generate-asymmetric-key to generate-hidden-key

   *  Added an install-hidden-key action

   *  Moved actions inside fo the "asymmetric-key" container

Watsen                  Expires 17 September 2024              [Page 49]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   *  Moved some groupings to draft-ietf-netconf-crypto-types

A.7.  06 to 07

   *  Removed a "require-instance false"

   *  Clarified some description statements

   *  Improved the keystore-usage examples

A.8.  07 to 08

   *  Added "inline-definition" containers to avoid posibility of the
      action/notification statements being under a "case" statement.

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

A.9.  08 to 09

   *  Added a 'description' statement to the 'must' in the /keystore/
      asymmetric-key node explaining that the descendant values may
      exist in <operational> only, and that implementation MUST assert
      that the values are either configured or that they exist in
      <operational>.

   *  Copied above 'must' statement (and description) into the inline-
      or-keystore-asymmetric-key-grouping, inline-or-keystore-
      asymmetric-key-with-certs-grouping, and inline-or-keystore-end-
      entity-cert-with-key-grouping statements.

A.10.  09 to 10

   *  Updated draft title to match new truststore draft title

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

   *  Renamed feature from 'local-keys-supported' to 'inline-
      definitions-supported' (same name used in truststore)

   *  Removed the either-all-or-none 'must' expressions for the key's
      3-tuple values (since the values are now 'mandatory true' in
      crypto-types)

   *  Example updated to reflect 'mandatory true' change in crypto-types
      draft

Watsen                  Expires 17 September 2024              [Page 50]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

A.11.  10 to 11

   *  Replaced typedef asymmetric-key-certificate-ref with grouping
      asymmetric-key-certificate-ref-grouping.

   *  Added feature feature 'key-generation'.

   *  Cloned groupings symmetric-key-grouping, asymmetric-key-pair-
      grouping, asymmetric-key-pair-with-cert-grouping, and asymmetric-
      key-pair-with-certs-grouping from crypto-keys, augmenting into
      each new case statements for values that have been encrypted by
      other keys in the keystore.  Refactored keystore model to use
      these groupings.

   *  Added new 'symmetric-keys' lists, as a sibling to the existing
      'asymmetric-keys' list.

   *  Added RPCs (not actions) 'generate-symmetric-key' and 'generate-
      asymmetric-key' to *return* a (potentially encrypted) key.

A.12.  11 to 12

   *  Updated to reflect crypto-type's draft using enumerations over
      identities.

   *  Added examples for the 'generate-symmetric-key' and 'generate-
      asymmetric-key' RPCs.

   *  Updated the Introduction section.

A.13.  12 to 13

   *  Updated examples to incorporate new "key-format" identities.

   *  Made the two "generate-*-key" RPCs be "action" statements instead.

A.14.  13 to 14

   *  Updated YANG module and examples to incorporate the new
      iana-*-algorithm modules in the crypto-types draft.

A.15.  14 to 15

   *  Added new "Support for Built-in Keys" section.

   *  Added 'must' expressions asserting that the 'key-format' leaf
      whenever an encrypted key is specified.

Watsen                  Expires 17 September 2024              [Page 51]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   *  Added inline-or-keystore-symmetric-key-grouping for PSK support.

A.16.  15 to 16

   *  Moved the generate key actions to ietf-crypt-types as RPCs, which
      are augmented by ietf-keystore to support encrypted keys.
      Examples updated accordingly.

   *  Added a SSH certificate-based key (RFC 6187) and a raw private key
      to the example instance document (partly so they could be
      referenced by examples in the SSH and TLS client/server drafts.

A.17.  16 to 17

   *  Removed augments to the "generate-symmetric-key" and "generate-
      asymmetric-key" groupings.

   *  Removed "generate-symmetric-key" and "generate-asymmetric-key"
      examples.

   *  Removed the "algorithm" nodes from remaining examples.

   *  Updated the "Support for Built-in Keys" section.

   *  Added new section "Encrypting Keys in Configuration".

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

A.18.  17 to 18

   *  Removed dangling/unnecessary ref to RFC 8342.

   *  r/MUST/SHOULD/ wrt strength of keys being configured over
      transports.

   *  Added an example for the "certificate-expiration" notification.

   *  Clarified that OS MAY have a multiplicity of underlying keystores
      and/or TPMs.

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

   *  Clarified the "Migrating Configuration to Another Server" section.

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

   *  Updated the Security Considerations section.

Watsen                  Expires 17 September 2024              [Page 52]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

A.19.  18 to 19

   *  Updated examples to reflect new "cleartext-" prefix in the crypto-
      types draft.

A.20.  19 to 20

   *  Addressed SecDir comments from Magnus Nystroem and Sandra Murphy.

A.21.  20 to 21

   *  Added a "Unconstrained Private Key Usage" Security Consideration
      to address concern raised by SecDir.

   *  (Editorial) Removed the output of "grouping" statements in the
      tree diagrams for the "ietf-keystore" and "ex-keystore-usage"
      modules.

   *  Addressed comments raised by YANG Doctor.

A.22.  21 to 22

   *  Added prefixes to 'path' statements per trust-anchors/issues/1

   *  Renamed feature "keystore-supported" to "central-keystore-
      supported".

   *  Associated with above, generally moved text to refer to a
      "central" keystore.

   *  Aligned modules with `pyang -f` formatting.

   *  Fixed nits found by YANG Doctor reviews.

A.23.  22 to 23

   *  Updated 802.1AR ref to latest version

   *  Replaced "base64encodedvalue==" with "BASE64VALUE=" in examples.

   *  Minor editorial nits

A.24.  23 to 24

   *  Added features "asymmetric-keys" and "symmetric-keys"

   *  fixup the 'WG Web' and 'WG List' lines in YANG module(s)

Watsen                  Expires 17 September 2024              [Page 53]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

   *  fixup copyright (i.e., s/Simplified/Revised/) in YANG module(s)

   *  Added Informative reference to ma-netmod-with-system

A.25.  24 to 25

   *  Added a "term" for "key" (IEEE liaison).

   *  Clarified draft text to ensure proper use of the "key" term.
      (IEEE liaison)

   *  Added statement that built-in keys SHOULD NOT be cleartext.  (IEEE
      liaison)

   *  Added "if-feature central-keystore-supported" to top-level
      "keystore" container.

A.26.  25 to 26

   *  Updated per Shepherd reviews impacting the suite of drafts.

A.27.  26 to 27

   *  Updated per Shepherd reviews impacting the suite of drafts.

A.28.  27 to 28

   *  Updated per Tom Petch review.

   *  s/local/inline/ in feature names, grouping names, and node names.

   *  Removed special handling text for built-in keys

   *  Updated section on built-in keys to read almost the same as the
      section in the trust-anchors draft.

A.29.  28 to 29

   *  Addresses AD review comments.

   *  Added note to Editor to fix line foldings.

   *  Renamed "keystore" to "central keystore" throughout.

   *  Renamed "encrypted-by-choice-grouping" to "encrypted-by-grouping".

   *  Removed "public-key-format" and "public-key" nodes from examples.

Watsen                  Expires 17 September 2024              [Page 54]
Internet-Draft  A YANG Data Model for a Keystore and Key      March 2024

A.30.  29 to 30

   *  Addresses Gen-ART review by Reese Enghardt.

   *  Addresses review by Tom Petch.

A.31.  30 to 31

   *  Addresses 1st-round of IESG reviews.

A.32.  31 to 33

   *  Addresses issues found in OpsDir review of the ssh-client-server
      draft.

   *  Renamed Security Considerations section s/Template for/
      Considerations for/

   *  s/defines/presents/ in a few places.

   *  Add refs to where the 'operational' and 'system' datastores are
      defined.

A.33.  33 to 34

   *  Nothing changed.  Only bumped for automation...

A.34.  34 to 35

   *  Address Roman Danyliw's comments.

Acknowledgements

   The authors would like to thank the following for lively discussions
   on list and in the halls (ordered by first name): Alan Luchuk, Andy
   Bierman, Benoit Claise, Bert Wijnen, Balázs Kovács, David Lamparter,
   Eric Voit, Éric Vyncke, Francesca Palombini, Ladislav Lhotka, Liang
   Xia, Jürgen Schönwälder, Mahesh Jethanandani, Magnus Nyström, Martin
   Björklund, Mehmet Ersue, Murray Kucherawy, Paul Wouters, Phil Shafer,
   Qin Wu, Radek Krejci, Ramkumar Dhanapal, Reese Enghardt, Reshad
   Rahman, Rob Wilton, Roman Danyliw, Sandra Murphy, Sean Turner, Tom
   Petch, Warren Kumari, and Zaheduzzaman Sarker.

Author's Address

   Kent Watsen
   Watsen Networks
   Email: kent+ietf@watsen.net

Watsen                  Expires 17 September 2024              [Page 55]