Internet-Draft Groupings for SSH Clients and Servers February 2024
Watsen Expires 11 August 2024 [Page]
Workgroup:
NETCONF Working Group
Internet-Draft:
draft-ietf-netconf-ssh-client-server-37
Published:
Intended Status:
Standards Track
Expires:
Author:
K. Watsen
Watsen Networks

YANG Groupings for SSH Clients and SSH Servers

Abstract

This document defines seven YANG 1.1 modules. Three "IETF" modules, and four supporting "IANA" modules.

The three IETF modules are: ietf-ssh-common, ietf-ssh-client, and ietf-ssh-server. The "ietf-ssh-client" and "ietf-ssh-server" modules are the primary productions of this work, enabling the configuration and monitoring of SSH clients and servers.

The four IANA modules are: iana-ssh-encryption-algs, iana-ssh-key-exchange-algs, iana-ssh-mac-algs, and iana-ssh-public-key-algs. These modules each define YANG identities for an IANA-maintained algorithm registry.

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:

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

The "Relation to other RFCs" section Section 1.2 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 1.2 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.

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 sections are to be removed prior to publication:

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 11 August 2024.

Table of Contents

1. Introduction

This document defines seven YANG 1.1 [RFC7950] modules. Three "IETF" modules and four "IANA" modules.

The three IETF modules include:

The four IANA modules include:

1.1. Regarding the IETF Modules

The three IETF modules define features and groupings to model "generic" SSH clients and SSH servers, where "generic" should be interpreted as "least common denominator" more so than "complete." Basic SSH protocol ([RFC4252], [RFC4253], and [RFC4254]) support is afforded by these modules, leaving configuration of advance features (e.g., multiple channels) to augmentations made by consuming modules.

It is intended that the YANG groupings will be used by applications needing to configure SSH client and server protocol stacks. For instance, these groupings are used to help define the data model for NETCONF over SSH [RFC6242] based clients and servers in [I-D.ietf-netconf-netconf-client-server].

The ietf-ssh-client and ietf-ssh-server YANG modules each define one grouping, which is focused on just SSH-specific configuration, and specifically avoids any transport-level configuration, such as what ports to listen on or connect to. This affords applications the opportunity to define their own strategy for how the underlying TCP connection is established. For instance, applications supporting NETCONF Call Home [RFC8071] could use the "ssh-server-grouping" grouping for the SSH parts it provides, while adding data nodes for the TCP-level call-home configuration.

The modules defined in this document optionally support [RFC6187] enabling X.509v3 certificate based host keys and public keys.

1.2. 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, enable 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

Table 1: Label in Diagram to RFC Mapping
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]

1.3. 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.

1.4. Adherence to the NMDA

This document is compliant with the Network Management Datastore Architecture (NMDA) [RFC8342]. For instance, as described in [I-D.ietf-netconf-trust-anchors] and [I-D.ietf-netconf-keystore], trust anchors and keys installed during manufacturing are expected to appear in <operational>.

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.

2. The "ietf-ssh-common" Module

The SSH common model presented in this section contains features and groupings common to both SSH clients and SSH servers. The "transport-params-grouping" grouping can be used to configure the list of SSH transport algorithms permitted by the SSH client or SSH server. The lists of permitted algorithms are in decreasing order of usage preference. The algorithm that appears first in the client list that also appears in the server list is the one that is used for the SSH transport layer connection. The ability to restrict the algorithms allowed is provided in this grouping for SSH clients and SSH servers that are capable of doing so and may serve to make SSH clients and SSH servers compliant with security policies.

2.1. Data Model Overview

This section provides an overview of the "ietf-ssh-common" module in terms of its features, identities, and groupings.

2.1.1. Features

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

Features:
  +-- ssh-x509-certs
  +-- transport-params
  +-- asymmetric-key-pair-generation
  +-- algorithm-discovery

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

2.1.2. Groupings

The "ietf-ssh-common" module defines the following "grouping" statement:

  • transport-params-grouping

This grouping is presented in the following subsection.

2.1.2.1. The "transport-params-grouping" Grouping

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

  grouping transport-params-grouping:
    +-- host-key
    |  +-- host-key-alg*   identityref
    +-- key-exchange
    |  +-- key-exchange-alg*   identityref
    +-- encryption
    |  +-- encryption-alg*   identityref
    +-- mac
       +-- mac-alg*   identityref

Comments:

  • This grouping is used by both the "ssh-client-grouping" and the "ssh-server-grouping" groupings defined in Section 3.1.2.1 and Section 4.1.2.1, respectively.
  • This grouping enables client and server configurations to specify the algorithms that are to be used when establishing SSH sessions.
  • Each list is "ordered-by user".

2.1.3. Protocol-accessible Nodes

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

module: ietf-ssh-common
  +--ro supported-algorithms {algorithm-discovery}?
     +--ro public-key-algorithms
     |  +--ro supported-algorithm*   sshpka:public-key-algorithm-ref
     +--ro encryption-algorithms
     |  +--ro supported-algorithm*   sshea:encryption-algorithm-ref
     +--ro key-exchange-algorithms
     |  +--ro supported-algorithm*
     |          sshkea:key-exchange-algorithm-ref
     +--ro mac-algorithms
        +--ro supported-algorithm*   sshma:mac-algorithm-ref

  rpcs:
    +---x generate-asymmetric-key-pair
            {asymmetric-key-pair-generation}?
       +---w input
       |  +---w algorithm
       |  |       sshpka:public-key-algorithm-ref
       |  +---w num-bits?               uint16
       |  +---w private-key-encoding
       |     +---w (private-key-encoding)
       |        +--:(cleartext) {ct:cleartext-private-keys}?
       |        |  +---w cleartext?   empty
       |        +--:(encrypted) {ct:encrypted-private-keys}?
       |        |  +---w encrypted
       |        |     +---w ks:encrypted-by-grouping
       |        +--:(hidden) {ct:hidden-private-keys}?
       |           +---w hidden?      empty
       +--ro output
          +---u ct:asymmetric-key-pair-grouping

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-ssh-common" module are limited to "supported-algorithms" container, which is constrained by the "algorithm-discovery" feature, and the RPC "generate-asymmetric-key-pair", which is constrained by the "asymmetric-key-pair-generation" feature.
  • The "encrypted-by-grouping" grouping is discussed in Section 2.1.3.1 of [I-D.ietf-netconf-keystore].
  • The "asymmetric-key-pair-grouping" grouping is discussed in Section 2.1.4.6 of [I-D.ietf-netconf-crypto-types].

2.2. Example Usage

The following example illustrates the "transport-params-grouping' grouping when populated with some data.

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

<!-- The outermost element below doesn't exist in the data model. -->
<!--  It simulates if the "grouping" were a "container" instead.  -->

<transport-params
  xmlns="urn:ietf:params:xml:ns:yang:ietf-ssh-common"
  xmlns:sshea="urn:ietf:params:xml:ns:yang:iana-ssh-encryption-algs"
  xmlns:sshkea="urn:ietf:params:xml:ns:yang:iana-ssh-key-exchange-al\
gs"
  xmlns:sshma="urn:ietf:params:xml:ns:yang:iana-ssh-mac-algs"
  xmlns:sshpka="urn:ietf:params:xml:ns:yang:iana-ssh-public-key-algs\
">
  <host-key>
    <host-key-alg>sshpka:x509v3-rsa2048-sha256</host-key-alg>
    <host-key-alg>sshpka:ssh-rsa</host-key-alg>
  </host-key>
  <key-exchange>
    <key-exchange-alg>sshkea:diffie-hellman-group-exchange-sha256</k\
ey-exchange-alg>
  </key-exchange>
  <encryption>
    <encryption-alg>sshea:aes256-ctr</encryption-alg>
    <encryption-alg>sshea:aes192-ctr</encryption-alg>
    <encryption-alg>sshea:aes128-ctr</encryption-alg>
    <encryption-alg>sshea:aes256-cbc</encryption-alg>
    <encryption-alg>sshea:aes192-cbc</encryption-alg>
    <encryption-alg>sshea:aes128-cbc</encryption-alg>
  </encryption>
  <mac>
    <mac-alg>sshma:hmac-sha2-256</mac-alg>
    <mac-alg>sshma:hmac-sha2-512</mac-alg>
  </mac>
</transport-params>

The following example illustrates operational state data indicating the SSH algorithms supported by the server.

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

<supported-algorithms
  xmlns="urn:ietf:params:xml:ns:yang:ietf-ssh-common">
  <encryption-algorithms
    xmlns:sshea="urn:ietf:params:xml:ns:yang:iana-ssh-encryption-alg\
s">
    <supported-algorithm>sshea:aes256-ctr</supported-algorithm>
    <supported-algorithm>sshea:aes256-cbc</supported-algorithm>
    <supported-algorithm>sshea:twofish256-cbc</supported-algorithm>
    <supported-algorithm>sshea:serpent256-cbc</supported-algorithm>
    <supported-algorithm>sshea:arcfour256</supported-algorithm>
    <supported-algorithm>sshea:serpent256-ctr</supported-algorithm>
    <supported-algorithm>sshea:aead-aes-256-gcm</supported-algorithm>
  </encryption-algorithms>
  <key-exchange-algorithms
    xmlns:sshkea="urn:ietf:params:xml:ns:yang:iana-ssh-key-exchange-\
algs">
    <supported-algorithm>sshkea:diffie-hellman-group-exchange-sha256\
</supported-algorithm>
    <supported-algorithm>sshkea:ecdh-sha2-nistp256</supported-algori\
thm>
    <supported-algorithm>sshkea:rsa2048-sha256</supported-algorithm>
    <supported-algorithm>sshkea:gss-group1-sha1-curve25519-sha256</s\
upported-algorithm>
    <supported-algorithm>sshkea:gss-group14-sha1-nistp256</supported\
-algorithm>
    <supported-algorithm>sshkea:gss-gex-sha1-nistp256</supported-alg\
orithm>
    <supported-algorithm>sshkea:gss-group14-sha256-1.2.840.10045.3.1\
.1</supported-algorithm>
    <supported-algorithm>sshkea:curve25519-sha256</supported-algorit\
hm>
  </key-exchange-algorithms>
  <mac-algorithms
    xmlns:sshma="urn:ietf:params:xml:ns:yang:iana-ssh-mac-algs">
    <supported-algorithm>sshma:hmac-sha2-256</supported-algorithm>
    <supported-algorithm>sshma:hmac-sha2-512</supported-algorithm>
    <supported-algorithm>sshma:aead-aes-256-gcm</supported-algorithm>
  </mac-algorithms>
  <public-key-algorithms
    xmlns:sshpka="urn:ietf:params:xml:ns:yang:iana-ssh-public-key-al\
gs">
    <supported-algorithm>sshpka:rsa-sha2-256</supported-algorithm>
    <supported-algorithm>sshpka:rsa-sha2-512</supported-algorithm>
    <supported-algorithm>sshpka:spki-sign-rsa</supported-algorithm>
    <supported-algorithm>sshpka:pgp-sign-dss</supported-algorithm>
    <supported-algorithm>sshpka:x509v3-rsa2048-sha256</supported-alg\
orithm>
    <supported-algorithm>sshpka:ecdsa-sha2-nistp256</supported-algor\
ithm>
    <supported-algorithm>sshpka:ecdsa-sha2-1.3.132.0.37</supported-a\
lgorithm>
    <supported-algorithm>sshpka:ssh-ed25519</supported-algorithm>
  </public-key-algorithms>
</supported-algorithms>

The following example illustrates the "generate-asymmetric-key-pair" RPC.

REQUEST

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

<rpc message-id="101"
  xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <generate-asymmetric-key-pair
    xmlns="urn:ietf:params:xml:ns:yang:ietf-ssh-common"
    xmlns:sshpka="urn:ietf:params:xml:ns:yang:iana-ssh-public-key-al\
gs">
    <algorithm>sshpka:ecdsa-sha2-nistp256</algorithm>
    <num-bits>521</num-bits>
    <private-key-encoding>
      <encrypted>
        <asymmetric-key-ref>hidden-asymmetric-key</asymmetric-key-re\
f>
      </encrypted>
    </private-key-encoding>
  </generate-asymmetric-key-pair>
</rpc>

RESPONSE

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

<rpc-reply message-id="101"
  xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
  xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types"
  xmlns:sshcmn="urn:ietf:params:xml:ns:yang:ietf-ssh-common">
  <sshcmn:public-key-format>ct:subject-public-key-info-format</sshcm\
n:public-key-format>
  <sshcmn:public-key>BASE64VALUE=</sshcmn:public-key>
  <sshcmn:private-key-format>ct:ec-private-key-format</sshcmn:privat\
e-key-format>
  <sshcmn:cleartext-private-key>BASE64VALUE=</sshcmn:cleartext-priva\
te-key>
</rpc-reply>

2.3. YANG Module

This YANG module has normative references to [RFC4253], [RFC4344], [RFC4419], [RFC5656], [RFC6187], [RFC6668], and [FIPS_186-6].

<CODE BEGINS> file "ietf-ssh-common@2024-02-08.yang"

module ietf-ssh-common {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-ssh-common";
  prefix sshcmn;

  import iana-ssh-encryption-algs {
    prefix sshea;
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  import iana-ssh-key-exchange-algs {
    prefix sshkea;
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  import iana-ssh-mac-algs {
    prefix sshma;
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  import iana-ssh-public-key-algs {
    prefix sshpka;
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

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

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

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

  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>
     Author:   Gary Wu <mailto:garywu@cisco.com>";

  description
    "This module defines a common features and groupings for
     Secure Shell (SSH).

     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 EEEE
     (https://www.rfc-editor.org/info/rfcEEEE); 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 2024-02-08 {
    description
      "Initial version";
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  // Features

  feature ssh-x509-certs {
    description
      "X.509v3 certificates are supported for SSH.";
    reference
      "RFC 6187: X.509v3 Certificates for Secure Shell
                 Authentication";
  }

  feature transport-params {
    description
      "SSH transport layer parameters are configurable.";
  }

  feature asymmetric-key-pair-generation {
    description
      "Indicates that the server implements the
       'generate-asymmetric-key-pair' RPC.";
  }

  feature algorithm-discovery {
    description
      "Indicates that the server implements the
       'supported-algorithms' container.";
  }


  // Groupings

  grouping transport-params-grouping {
    description
      "A reusable grouping for SSH transport parameters.";
    reference
      "RFC 4253: The Secure Shell (SSH) Transport Layer Protocol";
    container host-key {
      description
        "Parameters regarding host key.";
      leaf-list host-key-alg {
        type identityref {
          base sshpka:public-key-alg-base;
        }
        ordered-by user;
        description
          "Acceptable host key algorithms in order of decreasing
           preference.

           If this leaf-list is not configured (has zero elements)
           the acceptable host key algorithms are implementation-
           defined.";
        reference
          "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
      }
    }
    container key-exchange {
      description
        "Parameters regarding key exchange.";
      leaf-list key-exchange-alg {
        type identityref {
          base sshkea:key-exchange-alg-base;
        }
        ordered-by user;
        description
          "Acceptable key exchange algorithms in order of decreasing
           preference.

           If this leaf-list is not configured (has zero elements)
           the acceptable key exchange algorithms are implementation
           defined.";
      }
    }
    container encryption {
      description
        "Parameters regarding encryption.";
      leaf-list encryption-alg {
        type identityref {
          base sshea:encryption-alg-base;
        }
        ordered-by user;
        description
          "Acceptable encryption algorithms in order of decreasing
           preference.

           If this leaf-list is not configured (has zero elements)
           the acceptable encryption algorithms are implementation
           defined.";
      }
    }
    container mac {
      description
        "Parameters regarding message authentication code (MAC).";
      leaf-list mac-alg {
        type identityref {
          base sshma:mac-alg-base;
        }
        ordered-by user;
        description
          "Acceptable MAC algorithms in order of decreasing
           preference.

           If this leaf-list is not configured (has zero elements)
           the acceptable MAC algorithms are implementation-
           defined.";
      }
    }
  }

  // Protocol-accessible Nodes

  container supported-algorithms {
    if-feature "algorithm-discovery";
    config false;
    description
      "Identifies all of the supported algorithms.";
    container public-key-algorithms {
      description
        "A container for a list of public key algorithms
         supported by the server.";
      leaf-list supported-algorithm {
        type sshpka:public-key-algorithm-ref;
        description
          "A public key algorithm supported by the server.";
      }
    }
    container encryption-algorithms {
      description
        "A container for a list of encryption algorithms
         supported by the server.";
      leaf-list supported-algorithm {
        type sshea:encryption-algorithm-ref;
        description
          "An encryption algorithm supported by the server.";
      }
    }
    container key-exchange-algorithms {
      config false;
      description
        "A container for a list of key exchange algorithms
         supported by the server.";
      leaf-list supported-algorithm {
        type sshkea:key-exchange-algorithm-ref;
        description
          "A key exchange algorithm supported by the server.";
      }
    }
    container mac-algorithms {
      config false;
      description
        "A container for a list of MAC algorithms
         supported by the server.";
      leaf-list supported-algorithm {
        type sshma:mac-algorithm-ref;
        description
          "A MAC algorithm supported by the server.";
      }
    }
  }

  rpc generate-asymmetric-key-pair {
    if-feature "asymmetric-key-pair-generation";
    description
      "Requests the device to generate an public key using
       the specified key algorithm.";
    input {
      leaf algorithm {
        type sshpka:public-key-algorithm-ref;
        mandatory true;
        description
          "The algorithm to be used when generating the key.";
      }
      leaf num-bits {
        type uint16;
        description
          "Specifies the number of bits in the key to create.
           For RSA keys, the minimum size is 1024 bits and
           the default is 3072 bits. Generally, 3072 bits is
           considered sufficient. DSA keys must be exactly 1024
           bits as specified by FIPS 186-6.  For ECDSA keys, the
           'num-bits' value determines the key length by selecting
           from one of three elliptic curve sizes: 256, 384 or
           521 bits. Attempting to use bit lengths other than
           these three values for ECDSA keys will fail. ECDSA-SK,
           Ed25519 and Ed25519-SK keys have a fixed length and
           thus the 'num-bits' value is not specified.";
        reference
          "FIPS 186-6: Digital Signature Standard (DSS)";
      }
      container private-key-encoding {
        description
          "Indicates how the private key is to be encoded.";
        choice private-key-encoding {
          mandatory true;
          description
            "A choice amongst optional private key handling.";
          case cleartext {
            if-feature "ct:cleartext-private-keys";
            leaf cleartext {
              type empty;
              description
                "Indicates that the private key is to be returned
                 as a cleartext value.";
            }
          }
          case encrypted {
            if-feature "ct:encrypted-private-keys";
            container encrypted {
              description
                 "Indicates that the private key is to be encrypted
                  using the specified symmetric or asymmetric key.";
              uses ks:encrypted-by-grouping;
            }
          }
          case hidden {
            if-feature "ct:hidden-private-keys";
            leaf hidden {
              type empty;
              description
                "Indicates that the private key is to be hidden.

                 Unlike the 'cleartext' and 'encrypt' options, the
                 key returned is a placeholder for an internally
                 stored key.  See the 'Support for Built-in Keys'
                 section in RFC CCCC for information about hidden
                 keys.";
            }
          }
        }
      }
    }
    output {
      uses ct:asymmetric-key-pair-grouping;
    }
  } // end generate-asymmetric-key-pair

}

<CODE ENDS>

3. The "ietf-ssh-client" Module

This section defines a YANG 1.1 [RFC7950] module called "ietf-ssh-client". A high-level overview of the module is provided in Section 3.1. Examples illustrating the module's use are provided in Examples (Section 3.2). The YANG module itself is defined in Section 3.3.

3.1. Data Model Overview

This section provides an overview of the "ietf-ssh-client" module in terms of its features and groupings.

3.1.1. Features

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

Features:
  +-- ssh-client-keepalives
  +-- client-ident-password
  +-- client-ident-publickey
  +-- client-ident-hostbased
  +-- client-ident-none

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

3.1.2. Groupings

The "ietf-ssh-client" module defines the following "grouping" statement:

  • ssh-client-grouping

This grouping is presented in the following subsection.

3.1.2.1. The "ssh-client-grouping" Grouping

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

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

  grouping ssh-client-grouping:
    +-- client-identity
    |  +-- username?      string
    |  +-- public-key! {client-ident-publickey}?
    |  |  +---u ks:inline-or-keystore-asymmetric-key-grouping
    |  +-- password! {client-ident-password}?
    |  |  +---u ct:password-grouping
    |  +-- hostbased! {client-ident-hostbased}?
    |  |  +---u ks:inline-or-keystore-asymmetric-key-grouping
    |  +-- none?          empty {client-ident-none}?
    |  +-- certificate! {sshcmn:ssh-x509-certs}?
    |     +---u ks:inline-or-keystore-end-entity-cert-with-key-group\
ing
    +-- server-authentication
    |  +-- ssh-host-keys!
    |  |  +---u ts:inline-or-truststore-public-keys-grouping
    |  +-- ca-certs! {sshcmn:ssh-x509-certs}?
    |  |  +---u ts:inline-or-truststore-certs-grouping
    |  +-- ee-certs! {sshcmn:ssh-x509-certs}?
    |     +---u ts:inline-or-truststore-certs-grouping
    +-- transport-params {sshcmn:transport-params}?
    |  +---u sshcmn:transport-params-grouping
    +-- keepalives! {ssh-client-keepalives}?
       +-- max-wait?       uint16
       +-- max-attempts?   uint8

Comments:

  • The "client-identity" node configures a "username" and authentication methods, each enabled by a "feature" statement defined in Section 3.1.1.
  • The "server-authentication" node configures trust anchors for authenticating the SSH server, with each option enabled by a "feature" statement.
  • The "transport-params" node, which must be enabled by a feature, configures parameters for the SSH sessions established by this configuration.
  • The "keepalives" node, which must be enabled by a feature, configures a "presence" container for testing the aliveness of the SSH server. The aliveness-test occurs at the SSH protocol layer.
  • For the referenced grouping statement(s):

3.1.3. Protocol-accessible Nodes

The "ietf-ssh-client" module defines only "grouping" statements that are used by other modules to instantiate protocol-accessible nodes. Thus this module, when implemented, does not itself define any protocol-accessible nodes.

3.2. Example Usage

This section presents two examples showing the "ssh-client-grouping" grouping populated with some data. These examples are effectively the same except the first configures the client identity using a inlined key while the second uses a key configured in a keystore. Both examples are consistent with the examples presented in Section 2.2.1 of [I-D.ietf-netconf-trust-anchors] and Section 2.2.1 of [I-D.ietf-netconf-keystore].

The following configuration example uses inline-definitions for the client identity and server authentication:

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

<!-- The outermost element below doesn't exist in the data model. -->
<!--  It simulates if the "grouping" were a "container" instead.  -->

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

  <!-- how this client will authenticate itself to the server -->
  <client-identity>
    <username>foobar</username>
    <public-key>
      <inline-definition>
        <private-key-format>ct:rsa-private-key-format</private-key-f\
ormat>
        <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
      </inline-definition>
    </public-key>
  </client-identity>

  <!-- which host keys will this client trust -->
  <server-authentication>
    <ssh-host-keys>
      <inline-definition>
        <public-key>
          <name>corp-fw1</name>
          <public-key-format>ct:ssh-public-key-format</public-key-fo\
rmat>
          <public-key>BASE64VALUE=</public-key>
        </public-key>
        <public-key>
          <name>corp-fw2</name>
          <public-key-format>ct:ssh-public-key-format</public-key-fo\
rmat>
          <public-key>BASE64VALUE=</public-key>
        </public-key>
      </inline-definition>
    </ssh-host-keys>
    <ca-certs>
      <inline-definition>
        <certificate>
          <name>Server Cert Issuer #1</name>
          <cert-data>BASE64VALUE=</cert-data>
        </certificate>
        <certificate>
          <name>Server Cert Issuer #2</name>
          <cert-data>BASE64VALUE=</cert-data>
        </certificate>
      </inline-definition>
    </ca-certs>
    <ee-certs>
      <inline-definition>
        <certificate>
          <name>My Application #1</name>
          <cert-data>BASE64VALUE=</cert-data>
        </certificate>
        <certificate>
          <name>My Application #2</name>
          <cert-data>BASE64VALUE=</cert-data>
        </certificate>
      </inline-definition>
    </ee-certs>
  </server-authentication>

  <keepalives>
    <max-wait>30</max-wait>
    <max-attempts>3</max-attempts>
  </keepalives>

</ssh-client>

The following configuration example uses central-keystore-references for the client identity and central-truststore-references for server authentication: from the keystore:

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

<!-- The outermost element below doesn't exist in the data model. -->
<!--  It simulates if the "grouping" were a "container" instead.  -->

<ssh-client
  xmlns="urn:ietf:params:xml:ns:yang:ietf-ssh-client"
  xmlns:algs="urn:ietf:params:xml:ns:yang:ietf-ssh-common">

  <!-- how this client will authenticate itself to the server -->
  <client-identity>
    <username>foobar</username>
    <public-key>
      <central-keystore-reference>ssh-rsa-key</central-keystore-refe\
rence>
    </public-key>
    <certificate>
      <central-keystore-reference>
        <asymmetric-key>ssh-rsa-key-with-cert</asymmetric-key>
        <certificate>ex-rsa-cert2</certificate>
      </central-keystore-reference>
    </certificate>
  </client-identity>

  <!-- which host-keys will this client trust -->
  <server-authentication>
    <ssh-host-keys>
      <central-truststore-reference>trusted-ssh-public-keys</central\
-truststore-reference>
    </ssh-host-keys>
    <ca-certs>
      <central-truststore-reference>trusted-server-ca-certs</central\
-truststore-reference>
    </ca-certs>
    <ee-certs>
      <central-truststore-reference>trusted-server-ee-certs</central\
-truststore-reference>
    </ee-certs>
  </server-authentication>

  <keepalives>
    <max-wait>30</max-wait>
    <max-attempts>3</max-attempts>
  </keepalives>

</ssh-client>

3.3. YANG Module

This YANG module has normative references to [RFC4252], [RFC4254], [RFC8341], [I-D.ietf-netconf-crypto-types], [I-D.ietf-netconf-trust-anchors], and [I-D.ietf-netconf-keystore].

<CODE BEGINS> file "ietf-ssh-client@2024-02-08.yang"

module ietf-ssh-client {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-ssh-client";
  prefix sshc;

  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";
  }

  import ietf-truststore {
    prefix ts;
    reference
      "RFC BBBB: A YANG Data Model for a Truststore";
  }

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

  import ietf-ssh-common {
    prefix sshcmn;
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

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

  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 reusable grouping for SSH clients that
     can be used as a basis for specific SSH client instances.

     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 EEEE
     (https://www.rfc-editor.org/info/rfcEEEE); 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 2024-02-08 {
    description
      "Initial version";
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  // Features

  feature ssh-client-keepalives {
    description
      "Per socket SSH keepalive parameters are configurable for
       SSH clients on the server implementing this feature.";
  }

  feature client-ident-publickey {
    description
      "Indicates that the 'publickey' authentication type, per
       RFC 4252, is supported for client identification.
       The 'publickey' authentication type is required by
       RFC 4252, but common implementations allow it to
       be disabled.";
    reference
      "RFC 4252:
        The Secure Shell (SSH) Authentication Protocol";
  }

  feature client-ident-password {
    description
      "Indicates that the 'password' authentication type, per
       RFC 4252, is supported for client identification.";
    reference
      "RFC 4252:
        The Secure Shell (SSH) Authentication Protocol";
  }

  feature client-ident-hostbased {
    description
      "Indicates that the 'hostbased' authentication type, per
       RFC 4252, is supported for client identification.";
    reference
      "RFC 4252:
        The Secure Shell (SSH) Authentication Protocol";
  }

  feature client-ident-none {
    description
      "Indicates that the 'none' authentication type, per
       RFC 4252, is supported for client identification.
       It is NOT RECOMMENDED to enable this feature.";
    reference
      "RFC 4252:
        The Secure Shell (SSH) Authentication Protocol";
  }

  // Groupings

  grouping ssh-client-grouping {
    description
      "A reusable grouping for configuring a SSH client without
       any consideration for how an underlying TCP session is
       established.

       Note that this grouping uses fairly typical descendant
       node names such that a nesting of 'uses' statements will
       have name conflicts.  It is intended that the consuming
       data model will resolve the issue (e.g., by wrapping
       the 'uses' statement in a container called
       'ssh-client-parameters').  This model purposely does
       not do this itself so as to provide maximum flexibility
       to consuming models.";

    container client-identity {
      nacm:default-deny-write;
      description
        "The username and authentication methods for the client.
         The authentication methods are unordered.  Clients may
         initially send any configured method or, per RFC 4252,
         Section 5.2, send the 'none' method to prompt the server
         to provide a list of productive methods.  Whenever a
         choice amongst methods arises, implementations SHOULD
         use a default ordering that prioritizes automation
         over human-interaction.";
      leaf username {
        type string;
        description
          "The username of this user.  This will be the username
           used, for instance, to log into an SSH server.";
      }
      container public-key {
        if-feature "client-ident-publickey";
        presence
          "Indicates that publickey-based authentication has been
           configured.  This statement is present so the mandatory
           descendant nodes do not imply that this node must be
           configured.";
        description
          "A locally-defined or referenced asymmetric key
           pair to be used for client identification.";
        reference
          "RFC CCCC: A YANG Data Model for a Keystore";
        uses ks:inline-or-keystore-asymmetric-key-grouping {
          refine "inline-or-keystore/inline/inline-definition" {
            must 'not(public-key-format) or derived-from-or-self'
               + '(public-key-format, "ct:ssh-public-key-format")';
          }
          refine "inline-or-keystore/central-keystore/"
               + "central-keystore-reference" {
            must 'not(deref(.)/../ks:public-key-format) or derived-'
               + 'from-or-self(deref(.)/../ks:public-key-format, '
               + '"ct:ssh-public-key-format")';
          }
        }
      }
      container password {
        if-feature "client-ident-password";
        presence
          "Indicates that password-based authentication has been
           configured.  This statement is present so the mandatory
           descendant nodes do not imply that this node must be
           configured.";
        description
          "A password to be used to authenticate the client's
           identity.";
        uses ct:password-grouping;
      }
      container hostbased {
        if-feature "client-ident-hostbased";
        presence
          "Indicates that hostbased authentication is configured.
           This statement is present so the mandatory descendant
           nodes do not imply that this node must be configured.";
        description
          "A locally-defined or referenced asymmetric key
           pair to be used for host identification.";
        reference
          "RFC CCCC: A YANG Data Model for a Keystore";
        uses ks:inline-or-keystore-asymmetric-key-grouping {
          refine "inline-or-keystore/inline/inline-definition" {
            must 'not(public-key-format) or derived-from-or-self('
               + 'public-key-format, "ct:ssh-public-key-format")';
          }
          refine "inline-or-keystore/central-keystore/"
               + "central-keystore-reference" {
            must 'not(deref(.)/../ks:public-key-format) or derived-'
               + 'from-or-self(deref(.)/../ks:public-key-format, '
               + '"ct:ssh-public-key-format")';
          }
        }
      }
      leaf none {
        if-feature "client-ident-none";
        type empty;
        description
          "Indicates that 'none' algorithm is used for client
           identification.";
      }
      container certificate {
        if-feature "sshcmn:ssh-x509-certs";
        presence
          "Indicates that certificate-based authentication has been
           configured.  This statement is present so the mandatory
           descendant nodes do not imply that this node must be
           configured.";
        description
          "A locally-defined or referenced certificate
           to be used for client identification.";
        reference
          "RFC CCCC: A YANG Data Model for a Keystore";
        uses
          ks:inline-or-keystore-end-entity-cert-with-key-grouping {
          refine "inline-or-keystore/inline/inline-definition" {
            must 'not(public-key-format) or derived-from-or-self('
               + 'public-key-format, "ct:subject-public-key-info-'
               + 'format")';
          }
          refine "inline-or-keystore/central-keystore/"
               + "central-keystore-reference/asymmetric-key" {
            must 'not(deref(.)/../ks:public-key-format) or derived-'
               + 'from-or-self(deref(.)/../ks:public-key-format, '
               + '"ct:subject-public-key-info-format")';
          }
        }
      }
    } // container client-identity

    container server-authentication {
      nacm:default-deny-write;
      must 'ssh-host-keys or ca-certs or ee-certs';
      description
        "Specifies how the SSH client can authenticate SSH servers.
         Any combination of authentication methods is additive and
         unordered.";
      container ssh-host-keys {
        presence
          "Indicates that the SSH host key have been configured.
           This statement is present so the mandatory descendant
           nodes do not imply that this node must be configured.";
        description
          "A bag of SSH host keys used by the SSH client to
           authenticate SSH server host keys.  A server host key
           is authenticated if it is an exact match to a
           configured SSH host key.";
        reference
          "RFC BBBB: A YANG Data Model for a Truststore";
        uses ts:inline-or-truststore-public-keys-grouping {
          refine
            "inline-or-truststore/inline/inline-definition/public"
            + "-key" {
            must 'derived-from-or-self(public-key-format,'
               + ' "ct:ssh-public-key-format")';
          }
          refine "inline-or-truststore/central-truststore/"
               + "central-truststore-reference" {
            must 'not(deref(.)/../ts:public-key/ts:public-key-'
               + 'format[not(derived-from-or-self(., "ct:ssh-'
               + 'public-key-format"))])';
          }
        }
      }
      container ca-certs {
        if-feature "sshcmn:ssh-x509-certs";
        presence
          "Indicates that the CA certificates have been configured.
           This statement is present so the mandatory descendant
           nodes do not imply that this node must be configured.";
        description
          "A set of certificate authority (CA) certificates used by
           the SSH client to authenticate SSH servers.  A server
           is authenticated if its certificate has a valid chain
           of trust to a configured CA certificate.";
        reference
          "RFC BBBB: A YANG Data Model for a Truststore";
        uses ts:inline-or-truststore-certs-grouping;
      }
      container ee-certs {
        if-feature "sshcmn:ssh-x509-certs";
        presence
          "Indicates that the EE certificates have been configured.
           This statement is present so the mandatory descendant
           nodes do not imply that this node must be configured.";
        description
          "A set of end-entity certificates used by the SSH client
           to authenticate SSH servers.  A server is authenticated
           if its certificate is an exact match to a configured
           end-entity certificate.";
        reference
          "RFC BBBB: A YANG Data Model for a Truststore";
        uses ts:inline-or-truststore-certs-grouping;
      }
    } // container server-authentication

    container transport-params {
      nacm:default-deny-write;
      if-feature "sshcmn:transport-params";
      description
        "Configurable parameters of the SSH transport layer.";
      uses sshcmn:transport-params-grouping;
    } // container transport-parameters

    container keepalives {
      nacm:default-deny-write;
      if-feature "ssh-client-keepalives";
      presence
        "Indicates that the SSH client proactively tests the
         aliveness of the remote SSH server.";
      description
        "Configures the keep-alive policy, to proactively test
         the aliveness of the SSH server.  An unresponsive SSH
         server is dropped after approximately max-wait *
         max-attempts seconds.  Per Section 4 of RFC 4254,
         the SSH client SHOULD send an SSH_MSG_GLOBAL_REQUEST
         message with a purposely nonexistent 'request name'
         value (e.g., keepalive@ietf.org) and the 'want reply'
         value set to '1'.";
      reference
        "RFC 4254: The Secure Shell (SSH) Connection Protocol";
      leaf max-wait {
        type uint16 {
          range "1..max";
        }
        units "seconds";
        default "30";
        description
          "Sets the amount of time in seconds after which if
           no data has been received from the SSH server, a
           SSH-level message will be sent to test the
           aliveness of the SSH server.";
      }
      leaf max-attempts {
        type uint8;
        default "3";
        description
          "Sets the maximum number of sequential keep-alive
           messages that can fail to obtain a response from
           the SSH server before assuming the SSH server is
           no longer alive.";
      }
    } // container keepalives
  } // grouping ssh-client-grouping

}

<CODE ENDS>

4. The "ietf-ssh-server" Module

This section defines a YANG 1.1 module called "ietf-ssh-server". A high-level overview of the module is provided in Section 4.1. Examples illustrating the module's use are provided in Examples (Section 4.2). The YANG module itself is defined in Section 4.3.

4.1. Data Model Overview

This section provides an overview of the "ietf-ssh-server" module in terms of its features and groupings.

4.1.1. Features

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

Features:
  +-- ssh-server-keepalives
  +-- local-users-supported
  +-- local-user-auth-publickey {local-users-supported}?
  +-- local-user-auth-password {local-users-supported}?
  +-- local-user-auth-hostbased {local-users-supported}?
  +-- local-user-auth-none {local-users-supported}?

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

4.1.2. Groupings

The "ietf-ssh-server" module defines the following "grouping" statement:

  • ssh-server-grouping

This grouping is presented in the following subsection.

4.1.2.1. The "ssh-server-grouping" Grouping

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

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

  grouping ssh-server-grouping:
    +-- server-identity
    |  +-- host-key* [name]
    |     +-- name?                string
    |     +-- (host-key-type)
    |        +--:(public-key)
    |        |  +-- public-key
    |        |     +---u ks:inline-or-keystore-asymmetric-key-groupi\
ng
    |        +--:(certificate)
    |           +-- certificate {sshcmn:ssh-x509-certs}?
    |              +---u ks:inline-or-keystore-end-entity-cert-with-\
key-grouping
    +-- client-authentication
    |  +-- users {local-users-supported}?
    |  |  +-- user* [name]
    |  |     +-- name?          string
    |  |     +-- public-keys! {local-user-auth-publickey}?
    |  |     |  +---u ts:inline-or-truststore-public-keys-grouping
    |  |     +-- password
    |  |     |  +-- hashed-password?   ianach:crypt-hash
    |  |     |  |       {local-user-auth-password}?
    |  |     |  +--ro last-modified?     yang:date-and-time
    |  |     +-- hostbased! {local-user-auth-hostbased}?
    |  |     |  +---u ts:inline-or-truststore-public-keys-grouping
    |  |     +-- none?          empty {local-user-auth-none}?
    |  +-- ca-certs! {sshcmn:ssh-x509-certs}?
    |  |  +---u ts:inline-or-truststore-certs-grouping
    |  +-- ee-certs! {sshcmn:ssh-x509-certs}?
    |     +---u ts:inline-or-truststore-certs-grouping
    +-- transport-params {sshcmn:transport-params}?
    |  +---u sshcmn:transport-params-grouping
    +-- keepalives! {ssh-server-keepalives}?
       +-- max-wait?       uint16
       +-- max-attempts?   uint8

Comments:

  • The "server-identity" node configures the authentication methods the server can use to identify itself to clients. The ability to use a certificate is enabled by a "feature".
  • The "client-authentication" node configures trust anchors for authenticating the SSH client, with each option enabled by a "feature" statement.
  • The "transport-params" node, which must be enabled by a feature, configures parameters for the SSH sessions established by this configuration.
  • The "keepalives" node, which must be enabled by a feature, configures a "presence" container for testing the aliveness of the SSH client. The aliveness-test occurs at the SSH protocol layer.
  • For the referenced grouping statement(s):

4.1.3. Protocol-accessible Nodes

The "ietf-ssh-server" module defines only "grouping" statements that are used by other modules to instantiate protocol-accessible nodes. Thus this module, when implemented, does not itself define any protocol-accessible nodes.

4.2. Example Usage

This section presents two examples showing the "ssh-server-grouping" grouping populated with some data. These examples are effectively the same except the first configures the server identity using a inlined key while the second uses a key configured in a keystore. Both examples are consistent with the examples presented in Section 2.2.1 of [I-D.ietf-netconf-trust-anchors] and Section 2.2.1 of [I-D.ietf-netconf-keystore].

The following configuration example uses inline-definitions for the server identity and client authentication:

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

<!-- The outermost element below doesn't exist in the data model. -->
<!--  It simulates if the "grouping" were a "container" instead.  -->

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

  <!-- the host-key this SSH server will present -->
  <server-identity>
    <host-key>
      <name>my-pubkey-based-host-key</name>
      <public-key>
        <inline-definition>
          <private-key-format>ct:rsa-private-key-format</private-key\
-format>
          <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
        </inline-definition>
      </public-key>
    </host-key>
    <host-key>
      <name>my-cert-based-host-key</name>
      <certificate>
        <inline-definition>
          <private-key-format>ct:rsa-private-key-format</private-key\
-format>
          <cleartext-private-key>BASE64VALUE=</cleartext-private-key>
          <cert-data>BASE64VALUE=</cert-data>
        </inline-definition>
      </certificate>
    </host-key>
  </server-identity>

  <!-- the client credentials this SSH server will trust -->
  <client-authentication>
    <users>
      <user>
        <name>mary</name>
        <password>
          <hashed-password>$0$secret</hashed-password>
        </password>
        <public-keys>
          <inline-definition>
            <public-key>
              <name>Mary-Key-1</name>
              <public-key-format>ct:ssh-public-key-format</public-ke\
y-format>
              <public-key>BASE64VALUE=</public-key>
            </public-key>
            <public-key>
              <name>Mary-Key-2</name>
              <public-key-format>ct:ssh-public-key-format</public-ke\
y-format>
              <public-key>BASE64VALUE=</public-key>
            </public-key>
          </inline-definition>
        </public-keys>
      </user>
    </users>
    <ca-certs>
      <inline-definition>
        <certificate>
          <name>Identity Cert Issuer #1</name>
          <cert-data>BASE64VALUE=</cert-data>
        </certificate>
        <certificate>
          <name>Identity Cert Issuer #2</name>
          <cert-data>BASE64VALUE=</cert-data>
        </certificate>
      </inline-definition>
    </ca-certs>
    <ee-certs>
      <inline-definition>
        <certificate>
          <name>Application #1</name>
          <cert-data>BASE64VALUE=</cert-data>
        </certificate>
        <certificate>
          <name>Application #2</name>
          <cert-data>BASE64VALUE=</cert-data>
        </certificate>
      </inline-definition>
    </ee-certs>
  </client-authentication>

  <keepalives>
    <max-wait>30</max-wait>
    <max-attempts>3</max-attempts>
  </keepalives>

</ssh-server>

The following configuration example uses central-keystore-references for the server identity and central-truststore-references for client authentication: from the keystore:

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

<!-- The outermost element below doesn't exist in the data model. -->
<!--  It simulates if the "grouping" were a "container" instead.  -->

<ssh-server
  xmlns="urn:ietf:params:xml:ns:yang:ietf-ssh-server">

  <!-- the host-key this SSH server will present -->
  <server-identity>
    <host-key>
      <name>my-pubkey-based-host-key</name>
      <public-key>
        <central-keystore-reference>ssh-rsa-key</central-keystore-re\
ference>
      </public-key>
    </host-key>
    <host-key>
      <name>my-cert-based-host-key</name>
      <certificate>
        <central-keystore-reference>
          <asymmetric-key>ssh-rsa-key-with-cert</asymmetric-key>
          <certificate>ex-rsa-cert2</certificate>
        </central-keystore-reference>
      </certificate>
    </host-key>
  </server-identity>

  <!-- the client credentials this SSH server will trust -->
  <client-authentication>
    <users>
      <user>
        <name>mary</name>
        <password>
          <hashed-password>$0$secret</hashed-password>
        </password>
        <public-keys>
          <central-truststore-reference>SSH Public Keys for Applicat\
ion A</central-truststore-reference>
        </public-keys>
      </user>
    </users>
    <ca-certs>
      <central-truststore-reference>trusted-client-ca-certs</central\
-truststore-reference>
    </ca-certs>
    <ee-certs>
      <central-truststore-reference>trusted-client-ee-certs</central\
-truststore-reference>
    </ee-certs>
  </client-authentication>

  <keepalives>
    <max-wait>30</max-wait>
    <max-attempts>3</max-attempts>
  </keepalives>

</ssh-server>

4.3. YANG Module

This YANG module has references to [RFC4251], [RFC4252], [RFC4253], [RFC4254], [RFC7317], [RFC8341], [I-D.ietf-netconf-crypto-types], [I-D.ietf-netconf-trust-anchors], and [I-D.ietf-netconf-keystore].

<CODE BEGINS> file "ietf-ssh-server@2024-02-08.yang"

module ietf-ssh-server {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:ietf-ssh-server";
  prefix sshs;

  import ietf-yang-types {
    prefix yang;
    reference
      "RFC 6991: Common YANG Data Types";
  }

  import iana-crypt-hash {
    prefix ianach;
    reference
      "RFC 7317: A YANG Data Model for System Management";
  }

  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";
  }

  import ietf-truststore {
    prefix ts;
    reference
      "RFC BBBB: A YANG Data Model for a Truststore";
  }

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

  import ietf-ssh-common {
    prefix sshcmn;
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

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

  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 reusable grouping for SSH servers that
     can be used as a basis for specific SSH server instances.

     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 EEEE
     (https://www.rfc-editor.org/info/rfcEEEE); 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 2024-02-08 {
    description
      "Initial version";
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  // Features

  feature ssh-server-keepalives {
    description
      "Per socket SSH keepalive parameters are configurable for
       SSH servers on the server implementing this feature.";
  }

  feature local-users-supported {
    description
      "Indicates that the configuration for users can be
       configured herein, as opposed to in an application
       specific location.";
  }

  feature local-user-auth-publickey {
    if-feature "local-users-supported";
    description
      "Indicates that the 'publickey' authentication type,
       per RFC 4252, is supported for locally-defined users.
       The 'publickey' authentication type is required by
       RFC 4252, but common implementations allow it to
       be disabled.";
    reference
      "RFC 4252:
        The Secure Shell (SSH) Authentication Protocol";
  }

  feature local-user-auth-password {
    if-feature "local-users-supported";
    description
      "Indicates that the 'password' authentication type,
       per RFC 4252, is supported for locally-defined users.";
    reference
      "RFC 4252:
        The Secure Shell (SSH) Authentication Protocol";
  }

  feature local-user-auth-hostbased {
    if-feature "local-users-supported";
    description
      "Indicates that the 'hostbased' authentication type,
       per RFC 4252, is supported for locally-defined users.";
    reference
      "RFC 4252:
        The Secure Shell (SSH) Authentication Protocol";
  }

  feature local-user-auth-none {
    if-feature "local-users-supported";
    description
      "Indicates that the 'none' authentication type, per
       RFC 4252, is supported.  It is NOT RECOMMENDED to
       enable this feature.";
    reference
      "RFC 4252:
        The Secure Shell (SSH) Authentication Protocol";
  }

  // Groupings

  grouping ssh-server-grouping {
    description
      "A reusable grouping for configuring a SSH server without
       any consideration for how underlying TCP sessions are
       established.

       Note that this grouping uses fairly typical descendant
       node names such that a nesting of 'uses' statements will
       have name conflicts.  It is intended that the consuming
       data model will resolve the issue (e.g., by wrapping
       the 'uses' statement in a container called
       'ssh-server-parameters').  This model purposely does
       not do this itself so as to provide maximum flexibility
       to consuming models.";

    container server-identity {
      nacm:default-deny-write;
      description
        "The list of host keys the SSH server will present when
         establishing a SSH connection.";
      list host-key {
        key "name";
        min-elements 1;
        ordered-by user;
        description
          "An ordered list of host keys (see RFC 4251) the SSH
           server will use to construct its ordered list of
           algorithms, when sending its SSH_MSG_KEXINIT message,
           as defined in Section 7.1 of RFC 4253.";
        reference
          "RFC 4251: The Secure Shell (SSH) Protocol Architecture
           RFC 4253: The Secure Shell (SSH) Transport Layer
                     Protocol";
        leaf name {
          type string;
          description
            "An arbitrary name for this host key";
        }
        choice host-key-type {
          mandatory true;
          description
            "The type of host key being specified";
          container public-key {
            description
              "A locally-defined or referenced asymmetric key pair
               to be used for the SSH server's host key.";
            reference
              "RFC CCCC: A YANG Data Model for a Keystore";
            uses ks:inline-or-keystore-asymmetric-key-grouping {
              refine "inline-or-keystore/inline/inline-definition" {
                must 'not(public-key-format) or derived-from-or-self'
                 + '(public-key-format, "ct:ssh-public-key-format")';

              }
              refine "inline-or-keystore/central-keystore/"
                   + "central-keystore-reference" {
                must 'not(deref(.)/../ks:public-key-format) or '
                   + 'derived-from-or-self(deref(.)/../ks:public-'
                   + 'key-format, "ct:ssh-public-key-format")';
              }
            }
          }
          container certificate {
            if-feature "sshcmn:ssh-x509-certs";
            description
              "A locally-defined or referenced end-entity
               certificate to be used for the SSH server's
               host key.";
            reference
              "RFC CCCC: A YANG Data Model for a Keystore";
            uses
            ks:inline-or-keystore-end-entity-cert-with-key-grouping{
              refine "inline-or-keystore/inline/inline-definition" {
                must 'not(public-key-format) or derived-from-or-self'
                   + '(public-key-format, "ct:subject-public-key-'
                   + 'info-format")';
              }
              refine "inline-or-keystore/central-keystore/"
                   + "central-keystore-reference/asymmetric-key" {
                must 'not(deref(.)/../ks:public-key-format) or '
                   + 'derived-from-or-self(deref(.)/../ks:public-key'
                   + '-format, "ct:subject-public-key-info-format")';
              }
            }
          }
        }
      }
    } // container server-identity

    container client-authentication {
      nacm:default-deny-write;
      description
        "Specifies how the SSH server can be configured to
         authenticate SSH clients.  See RFC 4252 for a general
         discussion about SSH authentication.";
      reference
        "RFC 4252: The Secure Shell (SSH) Transport Layer";
      container users {
        if-feature "local-users-supported";
        description
          "A list of locally configured users.";
        list user {
          key "name";
          description
            "A locally configured user.

             The server SHOULD derive the list of authentication
             'method names' returned to the SSH client from the
             descendant nodes configured herein, per Sections
             5.1 and 5.2 in RFC 4252.

             The authentication methods are unordered.  Clients
             must authenticate to all configured methods.
             Whenever a choice amongst methods arises,
             implementations SHOULD use a default ordering
             that prioritizes automation over human-interaction.";
          leaf name {
            type string;
            description
              "The 'user name' for the SSH client, as defined in
               the SSH_MSG_USERAUTH_REQUEST message in RFC 4253.";
            reference
              "RFC 4253: The Secure Shell (SSH) Transport Layer
                         Protocol";
          }
          container public-keys {
            if-feature "local-user-auth-publickey";
            presence
              "Indicates that public keys have been configured.
               This statement is present so the mandatory descendant
               nodes do not imply that this node must be
               configured.";
            description
              "A set of SSH public keys may be used by the SSH
               server to authenticate this user.  A user is
               authenticated if its public key is an exact
               match to a configured public key.";
            reference
              "RFC BBBB: A YANG Data Model for a Truststore";
            uses ts:inline-or-truststore-public-keys-grouping {
              refine "inline-or-truststore/inline/inline-definition/"
                   + "public-key" {
                must 'derived-from-or-self(public-key-format,'
                   + ' "ct:ssh-public-key-format")';
              }
              refine "inline-or-truststore/central-truststore/"
                   + "central-truststore-reference" {
                must 'not(deref(.)/../ts:public-key/ts:public-key-'
                   + 'format[not(derived-from-or-self(., "ct:ssh-'
                   + 'public-key-format"))])';
              }
            }
          }
          container password {
            description
              "A password the SSH server may use to authenticate
               this user.  A user is authenticated if the hash
               of the supplied password matches this value.";
            leaf hashed-password {
              if-feature "local-user-auth-password";
              type ianach:crypt-hash;
              description
                "The password for this user.";
            }
            leaf last-modified {
              type yang:date-and-time;
              config false;
              description
                "Identifies when the password was last set.";
            }
          }
          container hostbased {
            if-feature "local-user-auth-hostbased";
            presence
              "Indicates that hostbased [RFC4252] keys have been
               configured.  This statement is present so the
               mandatory descendant nodes do not imply that this
               node must be configured.";
            description
              "A set of SSH host keys used by the SSH server to
               authenticate this user's host.  A user's host is
               authenticated if its host key is an exact match
               to a configured host key.";
            reference
              "RFC 4252: The Secure Shell (SSH) Transport Layer
               RFC BBBB: A YANG Data Model for a Truststore";
            uses ts:inline-or-truststore-public-keys-grouping {
              refine "inline-or-truststore/inline/inline-definition/"
                   + "public-key" {
                must 'derived-from-or-self(public-key-format,'
                   + ' "ct:ssh-public-key-format")';
              }
              refine "inline-or-truststore/central-truststore/"
                   + "central-truststore-reference" {
                must 'not(deref(.)/../ts:public-key/ts:public-key-'
                   + 'format[not(derived-from-or-self(., "ct:ssh-'
                   + 'public-key-format"))])';
              }
            }
          }
          leaf none {
            if-feature "local-user-auth-none";
            type empty;
            description
              "Indicates that the 'none' method is configured
               for this user.";
            reference
              "RFC 4252: The Secure Shell (SSH) Authentication
                         Protocol.";
          }
        }
      } // users
      container ca-certs {
        if-feature "sshcmn:ssh-x509-certs";
        presence
          "Indicates that CA certificates have been configured.
           This statement is present so the mandatory descendant
           nodes do not imply this node must be configured.";
        description
          "A set of certificate authority (CA) certificates used by
           the SSH server to authenticate SSH client certificates.
           A client certificate is authenticated if it has a valid
           chain of trust to a configured CA certificate.";
        reference
          "RFC BBBB: A YANG Data Model for a Truststore";
        uses ts:inline-or-truststore-certs-grouping;
      }
      container ee-certs {
        if-feature "sshcmn:ssh-x509-certs";
        presence
          "Indicates that EE certificates have been configured.
           This statement is present so the mandatory descendant
           nodes do not imply this node must be configured.";
        description
          "A set of client certificates (i.e., end entity
           certificates) used by the SSH server to authenticate
           the certificates presented by SSH clients.  A client
           certificate is authenticated if it is an exact match
           to a configured end-entity certificate.";
        reference
          "RFC BBBB: A YANG Data Model for a Truststore";
        uses ts:inline-or-truststore-certs-grouping;
      }
    } // container client-authentication

    container transport-params {
      nacm:default-deny-write;
      if-feature "sshcmn:transport-params";
      description
        "Configurable parameters of the SSH transport layer.";
      uses sshcmn:transport-params-grouping;
    } // container transport-params

    container keepalives {
      nacm:default-deny-write;
      if-feature "ssh-server-keepalives";
      presence
        "Indicates that the SSH server proactively tests the
         aliveness of the remote SSH client.";
      description
        "Configures the keep-alive policy, to proactively test
         the aliveness of the SSH client.  An unresponsive SSH
         client is dropped after approximately max-wait *
         max-attempts seconds.  Per Section 4 of RFC 4254,
         the SSH server SHOULD send an SSH_MSG_GLOBAL_REQUEST
         message with a purposely nonexistent 'request name'
         value (e.g., keepalive@ietf.org) and the 'want reply'
         value set to '1'.";
      reference
        "RFC 4254: The Secure Shell (SSH) Connection Protocol";
      leaf max-wait {
        type uint16 {
          range "1..max";
        }
        units "seconds";
        default "30";
        description
          "Sets the amount of time in seconds after which
           if no data has been received from the SSH client,
           a SSH-level message will be sent to test the
           aliveness of the SSH client.";
      }
      leaf max-attempts {
        type uint8;
        default "3";
        description
          "Sets the maximum number of sequential keep-alive
           messages that can fail to obtain a response from
           the SSH client before assuming the SSH client is
           no longer alive.";
      }
    }
  } // grouping ssh-server-grouping

}

<CODE ENDS>

5. Security Considerations

5.1. Considerations for the "iana-ssh-key-exchange-algs" Module

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

The "iana-ssh-key-exchange-algs" YANG module defines a data model that is designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.

The 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.

This YANG module defines YANG identities, for a public IANA-maintained registry, and a single protocol-accessible read-only node for the subset of those identities supported by a server.

YANG identities are not security-sensitive, as they are statically defined in the publicly-accessible YANG module. IANA MAY deprecate and/or obsolete identities over time as needed to address security issues found in the algorithms.

The protocol-accessible read-only node for the algorithms supported by a server is mildly sensitive, but not to the extent that special NACM annotations are needed to prevent read-access to regular authenticated administrators.

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

5.2. Considerations for the "iana-ssh-encryption-algs" Module

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

The "iana-ssh-encryption-algs" YANG module defines a data model that is designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.

The 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.

This YANG module defines YANG identities, for a public IANA-maintained registry, and a single protocol-accessible read-only node for the subset of those identities supported by a server.

YANG identities are not security-sensitive, as they are statically defined in the publicly-accessible YANG module.

The protocol-accessible read-only node for the algorithms supported by a server is mildly sensitive, but not to the extent that special NACM annotations are needed to prevent read-access to regular authenticated administrators.

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

5.3. Considerations for the "iana-ssh-mac-algs" Module

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

The "iana-ssh-mac-algs" YANG module defines a data model that is designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.

The 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.

This YANG module defines YANG identities, for a public IANA-maintained registry, and a single protocol-accessible read-only node for the subset of those identities supported by a server.

YANG identities are not security-sensitive, as they are statically defined in the publicly-accessible YANG module.

The protocol-accessible read-only node for the algorithms supported by a server is mildly sensitive, but not to the extent that special NACM annotations are needed to prevent read-access to regular authenticated administrators.

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

5.4. Considerations for the "iana-ssh-public-key-algs" Module

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

The "iana-ssh-public-key-algs" YANG module defines a data model that is designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.

The 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.

This YANG module defines YANG identities, for a public IANA-maintained registry, and a single protocol-accessible read-only node for the subset of those identities supported by a server.

YANG identities are not security-sensitive, as they are statically defined in the publicly-accessible YANG module.

The protocol-accessible read-only node for the algorithms supported by a server is mildly sensitive, but not to the extent that special NACM annotations are needed to prevent read-access to regular authenticated administrators.

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

5.5. Considerations for the "ietf-ssh-common" YANG Module

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

The "ietf-ssh-common" YANG module defines "grouping" statements that are designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.

The 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.

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

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

This module defines the RPC "generate-asymmetric-key-pair" that may, if the "ct:cleartext-private-keys" feature is enabled, and the client requests it, return the private clear in cleartext form. It is NOT RECOMMENDED for private keys to pass the server's security perimeter.

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

5.6. Considerations for the "ietf-ssh-client" YANG Module

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

The "ietf-ssh-client" YANG module defines "grouping" statements that are designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.

The 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.

Since this module only defines groupings, these considerations are primarily for the designers of other modules that use these groupings.

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.

One readable data node defined in this YANG module may be considered sensitive or vulnerable in some network environments. This node is as follows:

Please be aware that this module uses the "key" and "private-key" nodes from the "ietf-crypto-types" module [I-D.ietf-netconf-crypto-types], where said nodes have the NACM extension "default-deny-all" set, thus preventing unrestricted read-access to the cleartext key values.

All the writable data nodes defined by this module 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 RPCs, actions, or notifications, and thus the security consideration for such is not provided here.

5.7. Considerations for the "ietf-ssh-server" YANG Module

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

The "ietf-ssh-server" YANG module defines "grouping" statements that are designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.

The 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.

Since this module only defines groupings, these considerations are primarily for the designers of other modules that use these groupings.

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.

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

Please be aware that this module uses the "key" and "private-key" nodes from the "ietf-crypto-types" module [I-D.ietf-netconf-crypto-types], where said nodes have the NACM extension "default-deny-all" set, thus preventing unrestricted read-access to the cleartext key values.

All the writable data nodes defined by this module may be considered sensitive or vulnerable in some network environments. For instance, the addition or removal of references to keys, certificates, trusted anchors, etc., or even the modification of transport or keepalive parameters can dramatically alter the implemented security policy. For this reason, the NACM extension "default-deny-write" has been set for all data nodes defined in this module.

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

6. IANA Considerations

6.1. The "IETF XML" Registry

This document registers seven URIs in the "ns" subregistry of the IETF XML Registry [RFC3688]. Following the format in [RFC3688], the following registrations are requested:

URI: urn:ietf:params:xml:ns:yang:iana-ssh-key-exchange-algs
Registrant Contact: IANA
XML: N/A, the requested URI is an XML namespace.

URI: urn:ietf:params:xml:ns:yang:iana-ssh-encryption-algs
Registrant Contact: IANA
XML: N/A, the requested URI is an XML namespace.

URI: urn:ietf:params:xml:ns:yang:iana-ssh-mac-algs
Registrant Contact: IANA
XML: N/A, the requested URI is an XML namespace.

URI: urn:ietf:params:xml:ns:yang:iana-ssh-public-key-algs
Registrant Contact: IANA
XML: N/A, the requested URI is an XML namespace.

URI: urn:ietf:params:xml:ns:yang:ietf-ssh-common
Registrant Contact: The IESG
XML: N/A, the requested URI is an XML namespace.

URI: urn:ietf:params:xml:ns:yang:ietf-ssh-client
Registrant Contact: The IESG
XML: N/A, the requested URI is an XML namespace.

URI: urn:ietf:params:xml:ns:yang:ietf-ssh-server
Registrant Contact: The IESG
XML: N/A, the requested URI is an XML namespace.

6.2. The "YANG Module Names" Registry

This document registers seven YANG modules in the YANG Module Names registry [RFC6020]. Following the format in [RFC6020], the following registrations are requested:

name:         iana-ssh-key-exchange-algs
namespace:    urn:ietf:params:xml:ns:yang:iana-ssh-key-exchange-algs
prefix:       sshkea
reference:    RFC EEEE

name:         iana-ssh-encryption-algs
namespace:    urn:ietf:params:xml:ns:yang:iana-ssh-encryption-algs
prefix:       sshea
reference:    RFC EEEE

name:         iana-ssh-mac-algs
namespace:    urn:ietf:params:xml:ns:yang:iana-ssh-mac-algs
prefix:       sshma
reference:    RFC EEEE

name:         iana-ssh-public-key-algs
namespace:    urn:ietf:params:xml:ns:yang:iana-ssh-public-key-algs
prefix:       sshpka
reference:    RFC EEEE

name:         ietf-ssh-common
namespace:    urn:ietf:params:xml:ns:yang:ietf-ssh-common
prefix:       sshcmn
reference:    RFC EEEE

name:         ietf-ssh-client
namespace:    urn:ietf:params:xml:ns:yang:ietf-ssh-client
prefix:       sshc
reference:    RFC EEEE

name:         ietf-ssh-server
namespace:    urn:ietf:params:xml:ns:yang:ietf-ssh-server
prefix:       sshs
reference:    RFC EEEE

6.3. Considerations for the "iana-ssh-encryption-algs" Module

This section follows the template defined in Section 4.30.3.1 of [I-D.ietf-netmod-rfc8407bis].

This document defines the initial version of the IANA-maintained "iana-ssh-encryption-algs" YANG module. The most recent version of the YANG module is available from the "YANG Parameters" registry [IANA-YANG-PARAMETERS].

IANA is requested to add the following note to the registry:

New values must not be directly added to the "iana-ssh-encryption-algs" YANG module. They must instead be added to the "Encryption Algorithm Names" sub-registry of the "Secure Shell (SSH) Protocol Parameters" registry [IANA-ENC-ALGS].

When a value is added to the "Encryption Algorithm Names" sub-registry, a new "identity" statement must be added to the "iana-ssh-encryption-algs" YANG module. The name of the "identity" should be the same as name provided in the registry. If this name is a invalid for a YANG identity (see Section 4.3.1 of [RFC8407]), it is recommended to try spelling out the offending part (e.g., "triple-des-cbc" for "3des-cbc", since YANG identities cannot begin with a number). If this doesn't resolve the YANG validation issue, please request assistance from the NETCONF WG chairs.

The "identity" statement should have the following sub-statements defined:

base
Contains "encryption-alg-base".
status
Include only if a registration has been deprecated or obsoleted. IANA "Note" containing the word "HISTORIC" maps to YANG status "obsolete". Since the registry is unable to express a "SHOULD NOT" recommendation, there is no mapping to YANG status "deprecated".
description
Contains "Identity for the 'SSH_FOO' algorithm.", where "SSH_FOO" is a placeholder for the algorithm's name (e.g., "3des-cbc", not "triple-des-cbc").
reference
Replicates the reference(s) from the registry with the title of the document(s) added.

Unassigned or reserved values are not present in the module.

When the "iana-ssh-encryption-algs" YANG module is updated, a new "revision" statement with a unique revision date must be added in front of the existing revision statements. The "revision" statement must have a "reference" substatement that points to the where the module was published.

IANA is requested to add the following note to the "Encryption Algorithm Names" sub-registry.

When this registry is modified, the YANG module "iana-ssh-encryption-algs" [IANA-YANG-PARAMETERS] must be updated as defined in RFC EEEE.

An initial version of this module can be found in Appendix A.1.

6.4. Considerations for the "iana-ssh-mac-algs" Module

This section follows the template defined in Section 4.30.3.1 of [I-D.ietf-netmod-rfc8407bis].

This document defines the initial version of the IANA-maintained "iana-ssh-mac-algs" YANG module. The most recent version of the YANG module is available from the "YANG Parameters" registry [IANA-YANG-PARAMETERS].

IANA is requested to add the following note to the registry:

New values must not be directly added to the "iana-ssh-mac-algs" YANG module. They must instead be added to the "MAC Algorithm Names" sub-registry of the "Secure Shell (SSH) Protocol Parameters" registry [IANA-MAC-ALGS].

When a value is added to the "MAC Algorithm Names" sub-registry, a new "identity" statement must be added to the "iana-ssh-mac-algs" YANG module. The name of the "identity" should be the same as name provided in the registry. If this name is a invalid for a YANG identity (see Section 4.3.1 of [RFC8407]), it is recommended to try spelling out the offending part (e.g., "triple-des-cbc" for "3des-cbc", since YANG identities cannot begin with a number). If this doesn't resolve the YANG validation issue, please request assistance from the NETCONF WG chairs.

The "identity" statement should have the following sub-statements defined:

base
Contains "mac-alg-base".
status
Include only if a registration has been deprecated or obsoleted.
description
Contains "Identity for the 'SSH_FOO' algorithm.", where "SSH_FOO" is a placeholder for the algorithm's name (e.g., "3des-cbc", not "triple-des-cbc").
reference
Replicates the reference(s) from the registry with the title of the document(s) added.

Unassigned or reserved values are not present in the module.

When the "iana-ssh-mac-algs" YANG module is updated, a new "revision" statement with a unique revision date must be added in front of the existing revision statements. The "revision" statement must have a "reference" substatement that points to the where the module was published.

IANA is requested to add the following note to the "MAC Algorithm Names" sub-registry.

When this registry is modified, the YANG module "iana-ssh-mac-algs" [IANA-YANG-PARAMETERS] must be updated as defined in RFC EEEE.

An initial version of this module can be found in Appendix A.2.

6.5. Considerations for the "iana-ssh-public-key-algs" Module

This section follows the template defined in Section 4.30.3.1 of [I-D.ietf-netmod-rfc8407bis].

This document defines the initial version of the IANA-maintained "iana-ssh-public-key-algs" YANG module. The most recent version of the YANG module is available from the "YANG Parameters" registry [IANA-YANG-PARAMETERS].

IANA is requested to add the following note to the registry:

New values must not be directly added to the "iana-ssh-public-key-algs" YANG module. They must instead be added to the "Public Key Algorithm Names" sub-registry of the "Secure Shell (SSH) Protocol Parameters" registry [IANA-PUBKEY-ALGS].

When a value is added to the "MAC Algorithm Names" sub-registry, a new "identity" statement must be added to the "iana-ssh-public-key-algs" YANG module. The name of the "identity" should be the same as name provided in the registry. If this name is a invalid for a YANG identity (see Section 4.3.1 of [RFC8407]), it is recommended to try spelling out the offending part (e.g., "triple-des-cbc" for "3des-cbc", since YANG identities cannot begin with a number). If this doesn't resolve the YANG validation issue, please request assistance from the NETCONF WG chairs.

The "identity" statement should have the following sub-statements defined:

base
Contains "public-key-alg-base".
status
Include only if a registration has been deprecated or obsoleted.
description
Contains "Identity for the 'SSH_FOO' algorithm.", where "SSH_FOO" is a placeholder for the algorithm's name (e.g., "3des-cbc", not "triple-des-cbc").
reference
Replicates the reference(s) from the registry with the title of the document(s) added.

In the case that the algorithm name ends with "-*", the familiy of identities must be added. The familiy of identity algoritm names are generated by replacing the '*' character with these strings: "nistp256", "nistp384", "nistp521", "1.3.132.0.1", "1.2.840.10045.3.1.1", "1.3.132.0.33", "1.3.132.0.26", "1.3.132.0.27", "1.3.132.0.16", "1.3.132.0.36", "1.3.132.0.37", and "1.3.132.0.38".

Unassigned or reserved values are not present in the module.

When the "iana-ssh-public-key-algs" YANG module is updated, a new "revision" statement with a unique revision date must be added in front of the existing revision statements. The "revision" statement must have a "reference" substatement that points to the where the module was published.

IANA is requested to add the following note to the "MAC Algorithm Names" sub-registry.

When this registry is modified, the YANG module "iana-ssh-public-key-algs" [IANA-YANG-PARAMETERS] must be updated as defined in RFC EEEE.

An initial version of this module can be found in Appendix A.3.

6.6. Considerations for the "iana-ssh-key-exchange-algs" Module

This section follows the template defined in Section 4.30.3.1 of [I-D.ietf-netmod-rfc8407bis].

This document defines the initial version of the IANA-maintained "iana-ssh-key-exchange-algs" YANG module. The most recent version of the YANG module is available from the "YANG Parameters" registry [IANA-YANG-PARAMETERS].

IANA is requested to add the following note to the registry:

New values must not be directly added to the "iana-ssh-key-exchange-algs" YANG module. They must instead be added to the "Key Exchange Method Names" sub-registry of the "Secure Shell (SSH) Protocol Parameters" registry [IANA-KEYEX-ALGS].

When a value is added to the "Key Exchange Method Names" sub-registry, a new "identity" statement must be added to the "iana-ssh-key-exchange-algs" YANG module. The name of the "identity" should be the same as name provided in the registry. If this name is a invalid for a YANG identity (see Section 4.3.1 of [RFC8407]), it is recommended to try spelling out the offending part (e.g., "triple-des-cbc" for "3des-cbc", since YANG identities cannot begin with a number). If this doesn't resolve the YANG validation issue, please request assistance from the NETCONF WG chairs.

The "identity" statement should have the following sub-statements defined:

base
Contains "key-exchange-alg-base".
status
Include only if a registration has been deprecated or obsoleted. IANA "OK to Implement" containing "SHOULD NOT" maps to YANG status "deprecated". IANA "OK to Implement" containing "MUST NOT" maps to YANG status "obsolete".
description
Contains "Identity for the 'SSH_FOO' algorithm.", where "SSH_FOO" is a placeholder for the algorithm's name (e.g., "3des-cbc", not "triple-des-cbc").
reference
Replicates the reference(s) from the registry with the title of the document(s) added.

In the case that the algorithm name ends with "-*", the familiy of identities must be added. The familiy of identity algoritm names are generated by replacing the '*' character with these strings: "nistp256", "nistp384", "nistp521", "1.3.132.0.1", "1.2.840.10045.3.1.1", "1.3.132.0.33", "1.3.132.0.26", "1.3.132.0.27", "1.3.132.0.16", "1.3.132.0.36", "1.3.132.0.37", and "1.3.132.0.38".

Unassigned or reserved values are not present in the module.

When the "iana-ssh-key-exchange-algs" YANG module is updated, a new "revision" statement with a unique revision date must be added in front of the existing revision statements. The "revision" statement must have a "reference" substatement that points to the where the module was published.

IANA is requested to add the following note to the "Key Exchange Method Names" sub-registry.

When this registry is modified, the YANG module "iana-ssh-key-exchange-algs" [IANA-YANG-PARAMETERS] must be updated as defined in RFC EEEE.

An initial version of this module can be found in Appendix A.4.

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-29, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-crypto-types-29>.
[I-D.ietf-netconf-keystore]
Watsen, K., "A YANG Data Model for a Keystore", Work in Progress, Internet-Draft, draft-ietf-netconf-keystore-30, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-keystore-30>.
[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-23, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-trust-anchors-23>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
[RFC4251]
Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Protocol Architecture", RFC 4251, DOI 10.17487/RFC4251, , <https://www.rfc-editor.org/info/rfc4251>.
[RFC4252]
Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252, , <https://www.rfc-editor.org/info/rfc4252>.
[RFC4253]
Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253, , <https://www.rfc-editor.org/info/rfc4253>.
[RFC4254]
Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) Connection Protocol", RFC 4254, DOI 10.17487/RFC4254, , <https://www.rfc-editor.org/info/rfc4254>.
[RFC4344]
Bellare, M., Kohno, T., and C. Namprempre, "The Secure Shell (SSH) Transport Layer Encryption Modes", RFC 4344, DOI 10.17487/RFC4344, , <https://www.rfc-editor.org/info/rfc4344>.
[RFC4419]
Friedl, M., Provos, N., and W. Simpson, "Diffie-Hellman Group Exchange for the Secure Shell (SSH) Transport Layer Protocol", RFC 4419, DOI 10.17487/RFC4419, , <https://www.rfc-editor.org/info/rfc4419>.
[RFC4432]
Harris, B., "RSA Key Exchange for the Secure Shell (SSH) Transport Layer Protocol", RFC 4432, DOI 10.17487/RFC4432, , <https://www.rfc-editor.org/info/rfc4432>.
[RFC4462]
Hutzelman, J., Salowey, J., Galbraith, J., and V. Welch, "Generic Security Service Application Program Interface (GSS-API) Authentication and Key Exchange for the Secure Shell (SSH) Protocol", RFC 4462, DOI 10.17487/RFC4462, , <https://www.rfc-editor.org/info/rfc4462>.
[RFC5647]
Igoe, K. and J. Solinas, "AES Galois Counter Mode for the Secure Shell Transport Layer Protocol", RFC 5647, DOI 10.17487/RFC5647, , <https://www.rfc-editor.org/info/rfc5647>.
[RFC5656]
Stebila, D. and J. Green, "Elliptic Curve Algorithm Integration in the Secure Shell Transport Layer", RFC 5656, DOI 10.17487/RFC5656, , <https://www.rfc-editor.org/info/rfc5656>.
[RFC6020]
Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <https://www.rfc-editor.org/info/rfc6020>.
[RFC6187]
Igoe, K. and D. Stebila, "X.509v3 Certificates for Secure Shell Authentication", RFC 6187, DOI 10.17487/RFC6187, , <https://www.rfc-editor.org/info/rfc6187>.
[RFC6668]
Bider, D. and M. Baushke, "SHA-2 Data Integrity Verification for the Secure Shell (SSH) Transport Layer Protocol", RFC 6668, DOI 10.17487/RFC6668, , <https://www.rfc-editor.org/info/rfc6668>.
[RFC7317]
Bierman, A. and M. Bjorklund, "A YANG Data Model for System Management", RFC 7317, DOI 10.17487/RFC7317, , <https://www.rfc-editor.org/info/rfc7317>.
[RFC7950]
Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
[RFC8268]
Baushke, M., "More Modular Exponentiation (MODP) Diffie-Hellman (DH) Key Exchange (KEX) Groups for Secure Shell (SSH)", RFC 8268, DOI 10.17487/RFC8268, , <https://www.rfc-editor.org/info/rfc8268>.
[RFC8308]
Bider, D., "Extension Negotiation in the Secure Shell (SSH) Protocol", RFC 8308, DOI 10.17487/RFC8308, , <https://www.rfc-editor.org/info/rfc8308>.
[RFC8332]
Bider, D., "Use of RSA Keys with SHA-256 and SHA-512 in the Secure Shell (SSH) Protocol", RFC 8332, DOI 10.17487/RFC8332, , <https://www.rfc-editor.org/info/rfc8332>.
[RFC8341]
Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, , <https://www.rfc-editor.org/info/rfc8341>.
[RFC8709]
Harris, B. and L. Velvindron, "Ed25519 and Ed448 Public Key Algorithms for the Secure Shell (SSH) Protocol", RFC 8709, DOI 10.17487/RFC8709, , <https://www.rfc-editor.org/info/rfc8709>.
[RFC8731]
Adamantiadis, A., Josefsson, S., and M. Baushke, "Secure Shell (SSH) Key Exchange Method Using Curve25519 and Curve448", RFC 8731, DOI 10.17487/RFC8731, , <https://www.rfc-editor.org/info/rfc8731>.
[RFC8732]
Sorce, S. and H. Kario, "Generic Security Service Application Program Interface (GSS-API) Key Exchange with SHA-2", RFC 8732, DOI 10.17487/RFC8732, , <https://www.rfc-editor.org/info/rfc8732>.
[RFC8758]
Velvindron, L., "Deprecating RC4 in Secure Shell (SSH)", BCP 227, RFC 8758, DOI 10.17487/RFC8758, , <https://www.rfc-editor.org/info/rfc8758>.

7.2. Informative References

[FIPS_186-6]
(NIST), T. N. I. F. S. A. T., "Digital Signature Standard (DSS)", <https://csrc.nist.gov/publications/detail/fips/186/5/draft>.
[I-D.ietf-netconf-http-client-server]
Watsen, K., "YANG Groupings for HTTP 1.1/2.0 Clients and HTTP Servers", Work in Progress, Internet-Draft, draft-ietf-netconf-http-client-server-16, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-http-client-server-16>.
[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-31, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-netconf-client-server-31>.
[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-31, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-restconf-client-server-31>.
[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-35, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-ssh-client-server-35>.
[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-19, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-tcp-client-server-19>.
[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-37, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-tls-client-server-37>.
[I-D.ietf-netmod-rfc8407bis]
Boucadair, M. and Q. Wu, "Guidelines for Authors and Reviewers of Documents Containing YANG Data Models", Work in Progress, Internet-Draft, draft-ietf-netmod-rfc8407bis-06, , <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-rfc8407bis-06>.
[IANA-ENC-ALGS]
(IANA), I. A. N. A., "IANA "Encryption Algorithm Names" Sub-registry of the "Secure Shell (SSH) Protocol Parameters" Registry", <https://www.iana.org/assignments/ssh-parameters/ssh-parameters.xhtml#ssh-parameters-17>.
[IANA-KEYEX-ALGS]
(IANA), I. A. N. A., "IANA "Key Exchange Method Names" Sub-registry of the "Secure Shell (SSH) Protocol Parameters" Registry", <https://www.iana.org/assignments/ssh-parameters/ssh-parameters.xhtml#ssh-parameters-16>.
[IANA-MAC-ALGS]
(IANA), I. A. N. A., "IANA "MAC Algorithm Names" Sub-registry of the "Secure Shell (SSH) Protocol Parameters" Registry", <https://www.iana.org/assignments/ssh-parameters/ssh-parameters.xhtml#ssh-parameters-18>.
[IANA-PUBKEY-ALGS]
(IANA), I. A. N. A., "IANA "Public Key Algorithm Names" Sub-registry of the "Secure Shell (SSH) Protocol Parameters" Registry", <https://www.iana.org/assignments/ssh-parameters/ssh-parameters.xhtml#ssh-parameters-19>.
[IANA-YANG-PARAMETERS]
"YANG Parameters", n.d., <https://www.iana.org/assignments/yang-parameters>.
[RFC3688]
Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <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, , <https://www.rfc-editor.org/info/rfc6241>.
[RFC6242]
Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
[RFC8040]
Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
[RFC8071]
Watsen, K., "NETCONF Call Home and RESTCONF Call Home", RFC 8071, DOI 10.17487/RFC8071, , <https://www.rfc-editor.org/info/rfc8071>.
[RFC8340]
Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <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, , <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, , <https://www.rfc-editor.org/info/rfc8407>.

Appendix A. YANG Modules for IANA

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

The modules contained in this section were generated by the following script. Run the script using the command `python gen-idenities.py`, to produce four YANG module files in the current directory.

<CODE BEGINS> file "gen-identities.py"

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

import re
import csv
import textwrap
import requests
import requests_cache
from io import StringIO
from datetime import datetime

# Metadata for the four YANG modules produced by this script
MODULES = [
    {
        "csv_url": "https://www.iana.org/assignments/ssh-parameters/\
ssh-parameters-17.csv",
        "spaced_name": "encryption",
        "hypenated_name": "encryption",
        "prefix": "sshea",
        "description": """    "This module defines identities for th\
e encryption algorithms
     defined in the 'Encryption Algorithm Names' sub-registry of the
     'Secure Shell (SSH) Protocol Parameters' registry maintained
     by IANA.""",
    },
    {
        "csv_url": "https://www.iana.org/assignments/ssh-parameters/\
ssh-parameters-19.csv",
        "spaced_name": "public key",
        "hypenated_name": "public-key",
        "prefix": "sshpka",
        "description": """    "This module defines identities for th\
e public key algorithms
     defined in the 'Public Key Algorithm Names' sub-registry of the
     'Secure Shell (SSH) Protocol Parameters' registry maintained
     by IANA."""
    },
    {
        "csv_url": "https://www.iana.org/assignments/ssh-parameters/\
ssh-parameters-18.csv",
        "spaced_name": "mac",
        "hypenated_name": "mac",
        "prefix": "sshma",
        "description": """    "This module defines identities for th\
e MAC algorithms
     defined in the 'MAC Algorithm Names' sub-registry of the
     'Secure Shell (SSH) Protocol Parameters' registry maintained
     by IANA."""
    },
    {
        "csv_url": "https://www.iana.org/assignments/ssh-parameters/\
ssh-parameters-16.csv",
        "spaced_name": "key exchange",
        "hypenated_name": "key-exchange",
        "prefix": "sshkea",
        "description": """    "This module defines identities for th\
e key exchange algorithms
     defined in the 'Key Exchange Method Names' sub-registry of the
     'Secure Shell (SSH) Protocol Parameters' registry maintained
     by IANA."""
    },
]




def create_module_begin(module, f):

    # Define template for all four modules
    PREAMBLE_TEMPLATE="""
module iana-ssh-HNAME-algs {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:iana-ssh-HNAME-algs";
  prefix PREFIX;

  organization
    "Internet Assigned Numbers Authority (IANA)";

  contact
    "Postal: ICANN
             12025 Waterfront Drive, Suite 300
             Los Angeles, CA  90094-2536
             United States of America
     Tel:    +1 310 301 5800
     Email:  iana@iana.org";

  description
DESCRIPTION

     Copyright (c) YEAR 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).

     The initial version of this YANG module is part of RFC EEEE
     (https://www.rfc-editor.org/info/rfcEEEE); see the RFC
     itself for full legal notices.";

  revision DATE {
    description
      "Reflects contents of the SNAME algorithms registry.";
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  // Typedefs

  typedef HNAME-algorithm-ref {
    type identityref {
      base "HNAME-alg-base";
    }
    description
      "A reference to an SSH SNAME algorithm identifier.";
  }


  // Identities

  identity HNAME-alg-base {
    description
      "Base identity for SSH SNAME algorithms.";
  }
"""
    # Replacements
    rep = {
      "DATE": datetime.today().strftime('%Y-%m-%d'),
      "YEAR": datetime.today().strftime('%Y'),
      "SNAME": module["spaced_name"],
      "HNAME": module["hypenated_name"],
      "PREFIX": module["prefix"],
      "DESCRIPTION": module["description"]
    }

    # Do the replacement
    rep = dict((re.escape(k), v) for k, v in rep.items())
    pattern = re.compile("|".join(rep.keys()))
    text = pattern.sub(lambda m: rep[re.escape(m.group(0))], PREAMBL\
E_TEMPLATE)

    # Write preamble into the file
    f.write(text)


def create_module_body(module, f):

    # Fetch the current CSV file from IANA
    r = requests.get(module["csv_url"])
    assert(r.status_code == 200)

    # Ascertain the first CSV column's name
    with StringIO(r.text) as csv_file:
        csv_reader = csv.reader(csv_file)
        for row in csv_reader:
            first_colname = row[0]
            break

    # Parse each CSV line
    with StringIO(r.text) as csv_file:
        csv_reader = csv.DictReader(csv_file)
        for row in csv_reader:

            # Extract just the ref
            refs = row["Reference"][1:-1]  # remove the '[' and ']' \
chars
            refs = refs.split("][")

            # There may be more than one ref
            titles = []
            for ref in refs:

                # Ascertain the ref's title
                if ref.startswith("RFC"):

                    # Fetch the current BIBTEX entry
                    bibtex_url="https://datatracker.ietf.org/doc/"+ \
ref.lower() + "/bibtex/"
                    r = requests.get(bibtex_url)
                    assert r.status_code == 200, "Could not GET " + \
bibtex_url

                    # Append to 'titles' value from the "title" line
                    for item in r.text.split("\n"):
                        if "title =" in item:
                            titles.append(re.sub('.*{{(.*)}}.*', r'\\
g<1>', item))
                            break
                    else:
                        raise Exception("RFC title not found")


                    # Insert a space: "RFCXXXX" --> "RFC XXXX"
                    index = refs.index(ref)
                    refs[index] = "RFC " + ref[3:]

                elif ref.startswith("FIPS"):
                    # Special case for FIPS, since no bibtex to fetch
                    if ref == "FIPS 46-3" or ref == "FIPS-46-3":
                        titles.append("Data Encryption Standard (DES\
)")
                    else:
                        raise Exception("FIPS ref not found")

                else:
                    raise Exception("ref not found")

            # Function used below
            def write_identity(alg):
                f.write('\n')
                if row[first_colname].startswith("3des"):
                    f.write(f'  identity {re.sub("3des", "triple-des\
", alg)} {{\n')
                else:
                    f.write(f'  identity {alg} {{\n')
                f.write(f'    base {module["hypenated_name"]}-alg-ba\
se;\n')
                if "HISTORIC" in row["Note"]:
                    f.write(f'    status obsolete;\n')
                elif "OK to Implement" in row:
                    if "MUST NOT" in row["OK to Implement"]:
                        f.write(f'    status obsolete;\n')
                    elif "SHOULD NOT" in row["OK to Implement"]:
                        f.write(f'    status deprecated;\n')
                f.write(f'    description\n')
                description = f'      "Identity for the \'{alg}\' al\
gorithm.'
                if "Section" in row["Note"]:
                    description += "  " + row["Note"]
                description += '";'
                description = textwrap.fill(description, width=69, s\
ubsequent_indent="       ")
                f.write(f'{description}\n')
                f.write('    reference\n')
                f.write('      "')
                if row["Reference"] == "":
                    f.write('Missing in IANA registry.')
                else:
                    ref_len = len(refs)
                    for i in range(ref_len):
                        ref = refs[i]
                        f.write(f'{ref}:\n')
                        title = "         " + titles[i]
                        title = textwrap.fill(title, width=69, subse\
quent_indent="         ")
                        f.write(f'{title}')
                        if i != ref_len - 1:
                            f.write('\n       ')
                f.write('";\n')
                f.write('  }\n')


            # Write one or more "identity" statements
            if not row[first_colname].endswith("-*"): # just one ide\
ntity
                # Avoid duplicate entries caused by the "ecdh-sha2-*\
" family expansion
                if not row[first_colname].startswith("ecdh-sha2-nist\
p"):
                    write_identity(row[first_colname])
            else: # a family of identities
                curve_ids = [
                    "nistp256",
                    "nistp384",
                    "nistp521",
                    "1.3.132.0.1",
                    "1.2.840.10045.3.1.1",
                    "1.3.132.0.33",
                    "1.3.132.0.26",
                    "1.3.132.0.27",
                    "1.3.132.0.16",
                    "1.3.132.0.36",
                    "1.3.132.0.37",
                    "1.3.132.0.38",
                ]
                for curve_id in curve_ids:
                    write_identity(row[first_colname][:-1] + curve_i\
d)


def create_module_end(f):

    # Install cache for 8x speedup
    requests_cache.install_cache()

    # Write module's closing brace
    f.write('\n}\n')


def create_module(module):

    # ascertain yang module's name
    yang_module_name = "iana-ssh-" + module["hypenated_name"] + "-al\
gs.yang"

    # create yang module file
    with open(yang_module_name, "w") as f:
        create_module_begin(module, f)
        create_module_body(module, f)
        create_module_end(f)


def main():
    for module in MODULES:
        create_module(module)


if __name__ == "__main__":
    main()

<CODE ENDS>

A.1. Initial Module for the "Encryption Algorithm Names" Registry

A.1.1. Data Model Overview

This section provides an overview of the "iana-ssh-encryption-algs" module in terms of its identities and typedefs.

A.1.1.1. Identities

The following diagram lists the base "identity" statements defined in the module, of which there is just one, and illustrates that all the derived identity statements are generated from the associated IANA-maintained registry [IANA-ENC-ALGS].

Identities:
  +-- encryption-alg-base
    +-- <identity-name from IANA registry>

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

A.1.1.2. Typedefs

The following diagram illustrates the "typedef" statements defined in the "iana-ssh-encryption-algs" module:

Typedefs:
  identityref
    +-- encryption-algorithm-ref

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

Comments:

  • The typedef defined in the "iana-ssh-encryption-algs" module extends the "identityref" type defined in [RFC7950].

A.1.2. YANG Module

Following are the complete contents to the initial IANA-maintained YANG module. Please note that the date "2024-02-08" reflects the day on which the extraction occurred. Applications SHOULD use the IANA-maintained module, not the module defined in this draft.

This YANG module has normative references to [FIPS 46-3], [RFC4253], [RFC4344], [RFC5647], and [RFC8758].

<CODE BEGINS> file "iana-ssh-encryption-algs@2024-02-08.yang"


module iana-ssh-encryption-algs {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:iana-ssh-encryption-algs";
  prefix sshea;

  organization
    "Internet Assigned Numbers Authority (IANA)";

  contact
    "Postal: ICANN
             12025 Waterfront Drive, Suite 300
             Los Angeles, CA  90094-2536
             United States of America
     Tel:    +1 310 301 5800
     Email:  iana@iana.org";

  description
    "This module defines identities for the encryption algorithms
     defined in the 'Encryption Algorithm Names' sub-registry of the
     'Secure Shell (SSH) Protocol Parameters' registry maintained
     by IANA.

     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).

     The initial version of this YANG module is part of RFC EEEE
     (https://www.rfc-editor.org/info/rfcEEEE); see the RFC
     itself for full legal notices.";

  revision 2024-02-08 {
    description
      "Reflects contents of the encryption algorithms registry.";
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  // Typedefs

  typedef encryption-algorithm-ref {
    type identityref {
      base "encryption-alg-base";
    }
    description
      "A reference to an SSH encryption algorithm identifier.";
  }


  // Identities

  identity encryption-alg-base {
    description
      "Base identity for SSH encryption algorithms.";
  }

  identity triple-des-cbc {
    base encryption-alg-base;
    description
      "Identity for the '3des-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity blowfish-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'blowfish-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity twofish256-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'twofish256-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity twofish-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'twofish-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity twofish192-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'twofish192-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity twofish128-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'twofish128-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity aes256-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'aes256-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity aes192-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'aes192-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity aes128-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'aes128-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity serpent256-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'serpent256-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity serpent192-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'serpent192-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity serpent128-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'serpent128-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity arcfour {
    base encryption-alg-base;
    status obsolete;
    description
      "Identity for the 'arcfour' algorithm.";
    reference
      "RFC 8758:
         Deprecating RC4 in Secure Shell (SSH)";
  }

  identity idea-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'idea-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity cast128-cbc {
    base encryption-alg-base;
    description
      "Identity for the 'cast128-cbc' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity none {
    base encryption-alg-base;
    description
      "Identity for the 'none' algorithm.  Section 6.3";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity des-cbc {
    base encryption-alg-base;
    status obsolete;
    description
      "Identity for the 'des-cbc' algorithm.";
    reference
      "FIPS-46-3:
         Data Encryption Standard (DES)";
  }

  identity arcfour128 {
    base encryption-alg-base;
    status obsolete;
    description
      "Identity for the 'arcfour128' algorithm.";
    reference
      "RFC 8758:
         Deprecating RC4 in Secure Shell (SSH)";
  }

  identity arcfour256 {
    base encryption-alg-base;
    status obsolete;
    description
      "Identity for the 'arcfour256' algorithm.";
    reference
      "RFC 8758:
         Deprecating RC4 in Secure Shell (SSH)";
  }

  identity aes128-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'aes128-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity aes192-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'aes192-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity aes256-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'aes256-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity triple-des-ctr {
    base encryption-alg-base;
    description
      "Identity for the '3des-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity blowfish-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'blowfish-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity twofish128-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'twofish128-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity twofish192-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'twofish192-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity twofish256-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'twofish256-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity serpent128-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'serpent128-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity serpent192-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'serpent192-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity serpent256-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'serpent256-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity idea-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'idea-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity cast128-ctr {
    base encryption-alg-base;
    description
      "Identity for the 'cast128-ctr' algorithm.";
    reference
      "RFC 4344:
         The Secure Shell (SSH) Transport Layer Encryption Modes";
  }

  identity AEAD_AES_128_GCM {
    base encryption-alg-base;
    description
      "Identity for the 'AEAD_AES_128_GCM' algorithm.  Section 6.1";
    reference
      "RFC 5647:
         AES Galois Counter Mode for the Secure Shell Transport Layer
         Protocol";
  }

  identity AEAD_AES_256_GCM {
    base encryption-alg-base;
    description
      "Identity for the 'AEAD_AES_256_GCM' algorithm.  Section 6.2";
    reference
      "RFC 5647:
         AES Galois Counter Mode for the Secure Shell Transport Layer
         Protocol";
  }

}

<CODE ENDS>

A.2. Initial Module for the "MAC Algorithm Names" Registry

A.2.1. Data Model Overview

This section provides an overview of the "iana-ssh-mac-algs" module in terms of its identities and typedefs.

A.2.1.1. Identities

The following diagram lists the base "identity" statements defined in the module, of which there is just one, and illustrates that all the derived identity statements are generated from the associated IANA-maintained registry [IANA-MAC-ALGS].

Identities:
  +-- mac-alg-base
    +-- <identity-name from IANA registry>

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

A.2.1.2. Typedefs

The following diagram illustrates the "typedef" statements defined in the "iana-ssh-mac-algs" module:

Typedefs:
  identityref
    +-- mac-algorithm-ref

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

Comments:

  • The typedef defined in the "iana-ssh-mac-algs" module extends the "identityref" type defined in [RFC7950].

A.2.2. YANG Module

Following are the complete contents to the initial IANA-maintained YANG module. Please note that the date "2024-02-08" reflects the day on which the extraction occurred. Applications SHOULD use the IANA-maintained module, not the module defined in this draft.

This YANG module has normative references [RFC4253], [RFC5647], and [RFC6668].

<CODE BEGINS> file "iana-ssh-mac-algs@2024-02-08.yang"


module iana-ssh-mac-algs {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:iana-ssh-mac-algs";
  prefix sshma;

  organization
    "Internet Assigned Numbers Authority (IANA)";

  contact
    "Postal: ICANN
             12025 Waterfront Drive, Suite 300
             Los Angeles, CA  90094-2536
             United States of America
     Tel:    +1 310 301 5800
     Email:  iana@iana.org";

  description
    "This module defines identities for the MAC algorithms
     defined in the 'MAC Algorithm Names' sub-registry of the
     'Secure Shell (SSH) Protocol Parameters' registry maintained
     by IANA.

     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).

     The initial version of this YANG module is part of RFC EEEE
     (https://www.rfc-editor.org/info/rfcEEEE); see the RFC
     itself for full legal notices.";

  revision 2024-02-08 {
    description
      "Reflects contents of the mac algorithms registry.";
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  // Typedefs

  typedef mac-algorithm-ref {
    type identityref {
      base "mac-alg-base";
    }
    description
      "A reference to an SSH mac algorithm identifier.";
  }


  // Identities

  identity mac-alg-base {
    description
      "Base identity for SSH mac algorithms.";
  }

  identity hmac-sha1 {
    base mac-alg-base;
    description
      "Identity for the 'hmac-sha1' algorithm.  Section 6.4";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity hmac-sha1-96 {
    base mac-alg-base;
    description
      "Identity for the 'hmac-sha1-96' algorithm.  Section 6.4";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity hmac-md5 {
    base mac-alg-base;
    description
      "Identity for the 'hmac-md5' algorithm.  Section 6.4";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity hmac-md5-96 {
    base mac-alg-base;
    description
      "Identity for the 'hmac-md5-96' algorithm.  Section 6.4";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity none {
    base mac-alg-base;
    description
      "Identity for the 'none' algorithm.  Section 6.4";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity AEAD_AES_128_GCM {
    base mac-alg-base;
    description
      "Identity for the 'AEAD_AES_128_GCM' algorithm.  Section 6.1";
    reference
      "RFC 5647:
         AES Galois Counter Mode for the Secure Shell Transport Layer
         Protocol";
  }

  identity AEAD_AES_256_GCM {
    base mac-alg-base;
    description
      "Identity for the 'AEAD_AES_256_GCM' algorithm.  Section 6.2";
    reference
      "RFC 5647:
         AES Galois Counter Mode for the Secure Shell Transport Layer
         Protocol";
  }

  identity hmac-sha2-256 {
    base mac-alg-base;
    description
      "Identity for the 'hmac-sha2-256' algorithm.  Section 2";
    reference
      "RFC 6668:
         SHA-2 Data Integrity Verification for the Secure Shell (SSH)
         Transport Layer Protocol";
  }

  identity hmac-sha2-512 {
    base mac-alg-base;
    description
      "Identity for the 'hmac-sha2-512' algorithm.  Section 2";
    reference
      "RFC 6668:
         SHA-2 Data Integrity Verification for the Secure Shell (SSH)
         Transport Layer Protocol";
  }

}

<CODE ENDS>

A.3. Initial Module for the "Public Key Algorithm Names" Registry

A.3.1. Data Model Overview

This section provides an overview of the "iana-ssh-public-key-algs" module in terms of its identities and typedefs.

A.3.1.1. Identities

The following diagram lists the base "identity" statements defined in the module, of which there is just one, and illustrates that all the derived identity statements are generated from the associated IANA-maintained registry [IANA-PUBKEY-ALGS].

Identities:
  +-- public-key-alg-base
    +-- <identity-name from IANA registry>

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

A.3.1.2. Typedefs

The following diagram illustrates the "typedef" statements defined in the "iana-ssh-public-key-algs" module:

Typedefs:
  identityref
    +-- public-key-algorithm-ref

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

Comments:

  • The typedef defined in the "iana-ssh-public-key-algs" module extends the "identityref" type defined in [RFC7950].

A.3.2. YANG Module

Following are the complete contents to the initial IANA-maintained YANG module. Please note that the date "2024-02-08" reflects the day on which the extraction occurred. Applications SHOULD use the IANA-maintained module, not the module defined in this draft.

This YANG module has normative references [RFC4253], [RFC4462], [RFC5656], [RFC6187], [RFC8332], and [RFC8709].

<CODE BEGINS> file "iana-ssh-public-key-algs@2024-02-08.yang"


module iana-ssh-public-key-algs {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:iana-ssh-public-key-algs";
  prefix sshpka;

  organization
    "Internet Assigned Numbers Authority (IANA)";

  contact
    "Postal: ICANN
             12025 Waterfront Drive, Suite 300
             Los Angeles, CA  90094-2536
             United States of America
     Tel:    +1 310 301 5800
     Email:  iana@iana.org";

  description
    "This module defines identities for the public key algorithms
     defined in the 'Public Key Algorithm Names' sub-registry of the
     'Secure Shell (SSH) Protocol Parameters' registry maintained
     by IANA.

     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).

     The initial version of this YANG module is part of RFC EEEE
     (https://www.rfc-editor.org/info/rfcEEEE); see the RFC
     itself for full legal notices.";

  revision 2024-02-08 {
    description
      "Reflects contents of the public key algorithms registry.";
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  // Typedefs

  typedef public-key-algorithm-ref {
    type identityref {
      base "public-key-alg-base";
    }
    description
      "A reference to an SSH public key algorithm identifier.";
  }


  // Identities

  identity public-key-alg-base {
    description
      "Base identity for SSH public key algorithms.";
  }

  identity ssh-dss {
    base public-key-alg-base;
    description
      "Identity for the 'ssh-dss' algorithm.  Section 6.6";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity ssh-rsa {
    base public-key-alg-base;
    description
      "Identity for the 'ssh-rsa' algorithm.  Section 6.6";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity rsa-sha2-256 {
    base public-key-alg-base;
    description
      "Identity for the 'rsa-sha2-256' algorithm.  Section 3";
    reference
      "RFC 8332:
         Use of RSA Keys with SHA-256 and SHA-512 in the Secure Shell
         (SSH) Protocol";
  }

  identity rsa-sha2-512 {
    base public-key-alg-base;
    description
      "Identity for the 'rsa-sha2-512' algorithm.  Section 3";
    reference
      "RFC 8332:
         Use of RSA Keys with SHA-256 and SHA-512 in the Secure Shell
         (SSH) Protocol";
  }

  identity spki-sign-rsa {
    base public-key-alg-base;
    description
      "Identity for the 'spki-sign-rsa' algorithm.  Section 6.6";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity spki-sign-dss {
    base public-key-alg-base;
    description
      "Identity for the 'spki-sign-dss' algorithm.  Section 6.6";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity pgp-sign-rsa {
    base public-key-alg-base;
    description
      "Identity for the 'pgp-sign-rsa' algorithm.  Section 6.6";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity pgp-sign-dss {
    base public-key-alg-base;
    description
      "Identity for the 'pgp-sign-dss' algorithm.  Section 6.6";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity null {
    base public-key-alg-base;
    description
      "Identity for the 'null' algorithm.  Section 5";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol";
  }

  identity ecdsa-sha2-nistp256 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-nistp256' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-nistp384 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-nistp384' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-nistp521 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-nistp521' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.3.132.0.1 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.3.132.0.1' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.2.840.10045.3.1.1 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.2.840.10045.3.1.1' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.3.132.0.33 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.3.132.0.33' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.3.132.0.26 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.3.132.0.26' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.3.132.0.27 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.3.132.0.27' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.3.132.0.16 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.3.132.0.16' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.3.132.0.36 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.3.132.0.36' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.3.132.0.37 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.3.132.0.37' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdsa-sha2-1.3.132.0.38 {
    base public-key-alg-base;
    description
      "Identity for the 'ecdsa-sha2-1.3.132.0.38' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity x509v3-ssh-dss {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ssh-dss' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ssh-rsa {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ssh-rsa' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-rsa2048-sha256 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-rsa2048-sha256' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-nistp256 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-nistp256' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-nistp384 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-nistp384' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-nistp521 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-nistp521' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.3.132.0.1 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.3.132.0.1' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.2.840.10045.3.1.1 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.3.132.0.33 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.3.132.0.33' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.3.132.0.26 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.3.132.0.26' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.3.132.0.27 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.3.132.0.27' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.3.132.0.16 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.3.132.0.16' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.3.132.0.36 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.3.132.0.36' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.3.132.0.37 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.3.132.0.37' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity x509v3-ecdsa-sha2-1.3.132.0.38 {
    base public-key-alg-base;
    description
      "Identity for the 'x509v3-ecdsa-sha2-1.3.132.0.38' algorithm.";
    reference
      "RFC 6187:
         X.509v3 Certificates for Secure Shell Authentication";
  }

  identity ssh-ed25519 {
    base public-key-alg-base;
    description
      "Identity for the 'ssh-ed25519' algorithm.";
    reference
      "RFC 8709:
         Ed25519 and Ed448 Public Key Algorithms for the Secure Shell
         (SSH) Protocol";
  }

  identity ssh-ed448 {
    base public-key-alg-base;
    description
      "Identity for the 'ssh-ed448' algorithm.";
    reference
      "RFC 8709:
         Ed25519 and Ed448 Public Key Algorithms for the Secure Shell
         (SSH) Protocol";
  }

}

<CODE ENDS>

A.4. Initial Module for the "Key Exchange Method Names" Registry

A.4.1. Data Model Overview

This section provides an overview of the "iana-ssh-key-exchange-algs" module in terms of its identities and typedefs.

A.4.1.1. Identities

The following diagram lists the base "identity" statements defined in the module, of which there is just one, and illustrates that all the derived identity statements are generated from the associated IANA-maintained registry [IANA-KEYEX-ALGS].

Identities:
  +-- key-exchange-alg-base
    +-- <identity-name from IANA registry>

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

A.4.1.2. Typedefs

The following diagram illustrates the "typedef" statements defined in the "iana-ssh-key-exchange-algs" module:

Typedefs:
  identityref
    +-- key-exchange-algorithm-ref

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

Comments:

  • The typedef defined in the "iana-ssh-key-exchange-algs" module extends the "identityref" type defined in [RFC7950].

A.4.2. YANG Module

Following are the complete contents to the initial IANA-maintained YANG module. Please note that the date "2024-02-08" reflects the day on which the extraction occurred. Applications SHOULD use the IANA-maintained module, not the module defined in this draft.

This YANG module has normative references to [RFC4419], [RFC4432], [RFC5656], [RFC8268], [RFC8308], [RFC8731], [RFC8732].

<CODE BEGINS> file "iana-ssh-key-exchange-algs@2024-02-08.yang"


module iana-ssh-key-exchange-algs {
  yang-version 1.1;
  namespace "urn:ietf:params:xml:ns:yang:iana-ssh-key-exchange-algs";
  prefix sshkea;

  organization
    "Internet Assigned Numbers Authority (IANA)";

  contact
    "Postal: ICANN
             12025 Waterfront Drive, Suite 300
             Los Angeles, CA  90094-2536
             United States of America
     Tel:    +1 310 301 5800
     Email:  iana@iana.org";

  description
    "This module defines identities for the key exchange algorithms
     defined in the 'Key Exchange Method Names' sub-registry of the
     'Secure Shell (SSH) Protocol Parameters' registry maintained
     by IANA.

     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).

     The initial version of this YANG module is part of RFC EEEE
     (https://www.rfc-editor.org/info/rfcEEEE); see the RFC
     itself for full legal notices.";

  revision 2024-02-08 {
    description
      "Reflects contents of the key exchange algorithms registry.";
    reference
      "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers";
  }

  // Typedefs

  typedef key-exchange-algorithm-ref {
    type identityref {
      base "key-exchange-alg-base";
    }
    description
      "A reference to an SSH key exchange algorithm identifier.";
  }


  // Identities

  identity key-exchange-alg-base {
    description
      "Base identity for SSH key exchange algorithms.";
  }

  identity diffie-hellman-group-exchange-sha1 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'diffie-hellman-group-exchange-sha1'
       algorithm.  Section 4.1";
    reference
      "RFC 4419:
         Diffie-Hellman Group Exchange for the Secure Shell (SSH)
         Transport Layer Protocol
       RFC 8270:
         Increase the Secure Shell Minimum Recommended Diffie-Hellman
         Modulus Size to 2048 Bits";
  }

  identity diffie-hellman-group-exchange-sha256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'diffie-hellman-group-exchange-sha256'
       algorithm.  Section 4.2";
    reference
      "RFC 4419:
         Diffie-Hellman Group Exchange for the Secure Shell (SSH)
         Transport Layer Protocol
       RFC 8270:
         Increase the Secure Shell Minimum Recommended Diffie-Hellman
         Modulus Size to 2048 Bits";
  }

  identity diffie-hellman-group1-sha1 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'diffie-hellman-group1-sha1' algorithm.
       Section 8.1";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity diffie-hellman-group14-sha1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'diffie-hellman-group14-sha1' algorithm.
       Section 8.2";
    reference
      "RFC 4253:
         The Secure Shell (SSH) Transport Layer Protocol";
  }

  identity diffie-hellman-group14-sha256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'diffie-hellman-group14-sha256' algorithm.";
    reference
      "RFC 8268:
         More Modular Exponentiation (MODP) Diffie-Hellman (DH) Key
         Exchange (KEX) Groups for Secure Shell (SSH)";
  }

  identity diffie-hellman-group15-sha512 {
    base key-exchange-alg-base;
    description
      "Identity for the 'diffie-hellman-group15-sha512' algorithm.";
    reference
      "RFC 8268:
         More Modular Exponentiation (MODP) Diffie-Hellman (DH) Key
         Exchange (KEX) Groups for Secure Shell (SSH)";
  }

  identity diffie-hellman-group16-sha512 {
    base key-exchange-alg-base;
    description
      "Identity for the 'diffie-hellman-group16-sha512' algorithm.";
    reference
      "RFC 8268:
         More Modular Exponentiation (MODP) Diffie-Hellman (DH) Key
         Exchange (KEX) Groups for Secure Shell (SSH)";
  }

  identity diffie-hellman-group17-sha512 {
    base key-exchange-alg-base;
    description
      "Identity for the 'diffie-hellman-group17-sha512' algorithm.";
    reference
      "RFC 8268:
         More Modular Exponentiation (MODP) Diffie-Hellman (DH) Key
         Exchange (KEX) Groups for Secure Shell (SSH)";
  }

  identity diffie-hellman-group18-sha512 {
    base key-exchange-alg-base;
    description
      "Identity for the 'diffie-hellman-group18-sha512' algorithm.";
    reference
      "RFC 8268:
         More Modular Exponentiation (MODP) Diffie-Hellman (DH) Key
         Exchange (KEX) Groups for Secure Shell (SSH)";
  }

  identity ecdh-sha2-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-nistp256' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-nistp384' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-nistp521' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.3.132.0.1' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.2.840.10045.3.1.1' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.3.132.0.33' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.3.132.0.26' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.3.132.0.27' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.3.132.0.16' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.3.132.0.36' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.3.132.0.37' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecdh-sha2-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecdh-sha2-1.3.132.0.38' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity ecmqv-sha2 {
    base key-exchange-alg-base;
    description
      "Identity for the 'ecmqv-sha2' algorithm.";
    reference
      "RFC 5656:
         Elliptic Curve Algorithm Integration in the Secure Shell
         Transport Layer";
  }

  identity gss-group1-sha1-nistp256 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-nistp256' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-nistp384 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-nistp384' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-nistp521 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-nistp521' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.3.132.0.1 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.3.132.0.1' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.3.132.0.33 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.3.132.0.33' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.3.132.0.26 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.3.132.0.26' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.3.132.0.27 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.3.132.0.27' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.3.132.0.16 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.3.132.0.16' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.3.132.0.36 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.3.132.0.36' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.3.132.0.37 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.3.132.0.37' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group1-sha1-1.3.132.0.38 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group1-sha1-1.3.132.0.38' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-nistp256 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-nistp256' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-nistp384 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-nistp384' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-nistp521 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-nistp521' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.3.132.0.1 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.3.132.0.1' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.3.132.0.33 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.3.132.0.33' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.3.132.0.26 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.3.132.0.26' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.3.132.0.27 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.3.132.0.27' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.3.132.0.16 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.3.132.0.16' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.3.132.0.36 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.3.132.0.36' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.3.132.0.37 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.3.132.0.37' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha1-1.3.132.0.38 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-group14-sha1-1.3.132.0.38' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-nistp256 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-nistp256' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-nistp384 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-nistp384' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-nistp521 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-nistp521' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.3.132.0.1 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.3.132.0.1' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.3.132.0.33 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.3.132.0.33' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.3.132.0.26 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.3.132.0.26' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.3.132.0.27 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.3.132.0.27' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.3.132.0.16 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.3.132.0.16' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.3.132.0.36 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.3.132.0.36' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.3.132.0.37 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.3.132.0.37' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-gex-sha1-1.3.132.0.38 {
    base key-exchange-alg-base;
    status deprecated;
    description
      "Identity for the 'gss-gex-sha1-1.3.132.0.38' algorithm.";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol
       RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss- {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-' algorithm.  Section 2.6";
    reference
      "RFC 4462:
         Generic Security Service Application Program Interface (GSS-
         API) Authentication and Key Exchange for the Secure Shell
         (SSH) Protocol";
  }

  identity rsa1024-sha1 {
    base key-exchange-alg-base;
    status obsolete;
    description
      "Identity for the 'rsa1024-sha1' algorithm.";
    reference
      "RFC 4432:
         RSA Key Exchange for the Secure Shell (SSH) Transport Layer
         Protocol";
  }

  identity rsa2048-sha256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'rsa2048-sha256' algorithm.";
    reference
      "RFC 4432:
         RSA Key Exchange for the Secure Shell (SSH) Transport Layer
         Protocol";
  }

  identity ext-info-s {
    base key-exchange-alg-base;
    description
      "Identity for the 'ext-info-s' algorithm.  Section 2";
    reference
      "RFC 8308:
         Extension Negotiation in the Secure Shell (SSH) Protocol";
  }

  identity ext-info-c {
    base key-exchange-alg-base;
    description
      "Identity for the 'ext-info-c' algorithm.  Section 2";
    reference
      "RFC 8308:
         Extension Negotiation in the Secure Shell (SSH) Protocol";
  }

  identity gss-group14-sha256-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.3.132.0.1' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group14-sha256-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group14-sha256-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.3.132.0.1' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group15-sha512-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group15-sha512-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.3.132.0.1' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group16-sha512-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group16-sha512-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.3.132.0.1' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group17-sha512-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group17-sha512-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.3.132.0.1' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-group18-sha512-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-group18-sha512-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.3.132.0.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp256-sha256-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp256-sha256-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.3.132.0.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp384-sha384-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp384-sha384-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.3.132.0.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-nistp521-sha512-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-nistp521-sha512-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.3.132.0.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve25519-sha256-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve25519-sha256-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-nistp256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-nistp256' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-nistp384 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-nistp384' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-nistp521 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-nistp521' algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.3.132.0.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.3.132.0.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.2.840.10045.3.1.1 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.2.840.10045.3.1.1'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.3.132.0.33 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.3.132.0.33'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.3.132.0.26 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.3.132.0.26'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.3.132.0.27 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.3.132.0.27'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.3.132.0.16 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.3.132.0.16'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.3.132.0.36 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.3.132.0.36'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.3.132.0.37 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.3.132.0.37'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity gss-curve448-sha512-1.3.132.0.38 {
    base key-exchange-alg-base;
    description
      "Identity for the 'gss-curve448-sha512-1.3.132.0.38'
       algorithm.";
    reference
      "RFC 8732:
         Generic Security Service Application Program Interface (GSS-
         API) Key Exchange with SHA-2";
  }

  identity curve25519-sha256 {
    base key-exchange-alg-base;
    description
      "Identity for the 'curve25519-sha256' algorithm.";
    reference
      "RFC 8731:
         Secure Shell (SSH) Key Exchange Method Using Curve25519 and
         Curve448";
  }

  identity curve448-sha512 {
    base key-exchange-alg-base;
    description
      "Identity for the 'curve448-sha512' algorithm.";
    reference
      "RFC 8731:
         Secure Shell (SSH) Key Exchange Method Using Curve25519 and
         Curve448";
  }

}

<CODE ENDS>

Appendix B. Change Log

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

B.1. 00 to 01

  • Noted that '0.0.0.0' and '::' might have special meanings.
  • Renamed "keychain" to "keystore".

B.2. 01 to 02

  • Removed the groupings 'listening-ssh-client-grouping' and 'listening-ssh-server-grouping'. Now modules only contain the transport-independent groupings.
  • Simplified the "client-auth" part in the ietf-ssh-client module. It now inlines what it used to point to keystore for.
  • Added cipher suites for various algorithms into new 'ietf-ssh-common' module.

B.3. 02 to 03

  • Removed 'RESTRICTED' enum from 'password' leaf type.
  • Added a 'must' statement to container 'server-auth' asserting that at least one of the various auth mechanisms must be specified.
  • Fixed description statement for leaf 'trusted-ca-certs'.

B.4. 03 to 04

  • Change title to "YANG Groupings for SSH Clients and SSH Servers"
  • Added reference to RFC 6668
  • Added RFC 8174 to Requirements Language Section.
  • Enhanced description statement for ietf-ssh-server's "trusted-ca-certs" leaf.
  • Added mandatory true to ietf-ssh-client's "client-auth" 'choice' statement.
  • Changed the YANG prefix for module ietf-ssh-common from 'sshcom' to 'sshcmn'.
  • Removed the compression algorithms as they are not commonly configurable in vendors' implementations.
  • Updating descriptions in transport-params-grouping and the servers's usage of it.
  • Now tree diagrams reference ietf-netmod-yang-tree-diagrams
  • Updated YANG to use typedefs around leafrefs to common keystore paths
  • Now inlines key and certificates (no longer a leafref to keystore)

B.5. 04 to 05

  • Merged changes from co-author.

B.6. 05 to 06

  • Updated to use trust anchors from trust-anchors draft (was keystore draft)
  • Now uses new keystore grouping enabling asymmetric key to be either locally defined or a reference to the keystore.

B.7. 06 to 07

  • factored the ssh-[client|server]-groupings into more reusable groupings.
  • added if-feature statements for the new "ssh-host-keys" and "x509-certificates" features defined in draft-ietf-netconf-trust-anchors.

B.8. 07 to 08

  • Added a number of compatibility matrices to Section 5 (thanks Frank!)
  • Clarified that any configured "host-key-alg" values need to be compatible with the configured private key.

B.9. 08 to 09

  • Updated examples to reflect update to groupings defined in the keystore -09 draft.
  • Add SSH keepalives features and groupings.
  • Prefixed top-level SSH grouping nodes with 'ssh-' and support mashups.
  • Updated copyright date, boilerplate template, affiliation, and folding algorithm.

B.10. 09 to 10

  • Reformatted the YANG modules.

B.11. 10 to 11

  • Reformatted lines causing folding to occur.

B.12. 11 to 12

  • Collapsed all the inner groupings into the top-level grouping.
  • Added a top-level "demux container" inside the top-level grouping.
  • Added NACM statements and updated the Security Considerations section.
  • Added "presence" statements on the "keepalive" containers, as was needed to address a validation error that appeared after adding the "must" statements into the NETCONF/RESTCONF client/server modules.
  • Updated the boilerplate text in module-level "description" statement to match copyeditor convention.

B.13. 12 to 13

  • Removed the "demux containers", floating the nacm:default-deny-write to each descendant node, and adding a note to model designers regarding the potential need to add their own demux containers.
  • Fixed a couple references (section 2 --> section 3)
  • In the server model, replaced <client-cert-auth> with <client-authentication> and introduced 'inline-or-external' choice.

B.14. 13 to 14

  • Updated to reflect changes in trust-anchors drafts (e.g., s/trust-anchors/truststore/g + s/pinned.//)

B.15. 14 to 15

  • Updated examples to reflect ietf-crypto-types change (e.g., identities --> enumerations)
  • Updated "server-authentication" and "client-authentication" nodes from being a leaf of type "ts:host-keys-ref" or "ts:certificates-ref" to a container that uses "ts:inline-or-truststore-host-keys-grouping" or "ts:inline-or-truststore-certs-grouping".

B.16. 15 to 16

  • Removed unnecessary if-feature statements in the -client and -server modules.
  • Cleaned up some description statements in the -client and -server modules.
  • Fixed a canonical ordering issue in ietf-ssh-common detected by new pyang.

B.17. 16 to 17

  • Removed choice inline-or-external by removing the 'external' case and flattening the 'local' case and adding a "local-users-supported" feature.
  • Updated examples to include the "*-key-format" nodes.
  • Augmented-in "must" expressions ensuring that locally-defined public-key-format are "ct:ssh-public-key-format" (must expr for ref'ed keys are TBD).

B.18. 17 to 18

  • Removed leaf-list 'other' from ietf-ssh-server.
  • Removed unused 'external-client-auth-supported' feature.
  • Added features client-auth-password, client-auth-hostbased, and client-auth-none.
  • Renamed 'host-key' to 'public-key' for when refering to 'publickey' based auth.
  • Added new feature-protected 'hostbased' and 'none' to the 'user' node's config.
  • Added new feature-protected 'hostbased' and 'none' to the 'client-identity' node's config.
  • Updated examples to reflect new "bag" addition to truststore.
  • Refined truststore/keystore groupings to ensure the key formats "must" be particular values.
  • Switched to using truststore's new "public-key" bag (instead of separate "ssh-public-key" and "raw-public-key" bags.
  • Updated client/server examples to cover ALL cases (local/ref x cert/raw-key/psk).

B.19. 18 to 19

  • Updated the "keepalives" containers to address Michal Vasko's request to align with RFC 8071.
  • Removed algorithm-mapping tables from the "SSH Common Model" section
  • Removed 'algorithm' node from examples.
  • Added feature "userauth-publickey"
  • Removed "choice auth-type", as auth-types are not exclusive.
  • Renamed both "client-certs" and "server-certs" to "ee-certs"
  • Switch "must" to assert the public-key-format is "subject-public-key-info-format" when certificates are used.
  • Added a "Note to Reviewers" note to first page.

B.20. 19 to 20

  • Added a "must 'public-key or password or hostbased or none or certificate'" statement to the "user" node in ietf-ssh-client
  • Expanded "Data Model Overview section(s) [remove "wall" of tree diagrams].
  • Moved the "ietf-ssh-common" module section to proceed the other two module sections.
  • Updated the Security Considerations section.

B.21. 20 to 21

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

B.22. 21 to 22

  • Cleaned up the SSH-client examples (i.e., removing FIXMEs)
  • Fixed issues found by the SecDir review of the "keystore" draft.
  • Updated the "ietf-ssh-client" module to use the new "password-grouping" grouping from the "crypto-types" module.

B.23. 22 to 23

  • Addressed comments raised by YANG Doctor in the ct/ts/ks drafts.

B.24. 23 to 24

  • Removed the 'supported-authentication-methods' from {grouping ssh-server-grouping}/client-authentication.
  • Added XML-comment above examples explaining the reason for the unexepected top-most element's presence.
  • Added RFC-references to various 'feature' statements.
  • Renamed "credentials" to "authentication methods"
  • Renamed "client-auth-*" to "userauth-*"
  • Renamed "client-identity-*" to "userauth-*"
  • Fixed nits found by YANG Doctor reviews.
  • Aligned modules with `pyang -f` formatting.
  • Added a 'Contributors' section.

B.25. 24 to 25

  • Moved algorithms in ietf-ssh-common (plus more) to IANA-maintained modules
  • Added "config false" lists for algorithms supported by the server.
  • Renamed "{ietf-ssh-client}userauth-*" to "client-ident-*"
  • Renamed "{ietf-ssh-server}userauth-*" to "local-user-auth-*"
  • Fixed issues found during YANG Doctor review.
  • Fixed issues found during Secdir review.

B.26. 25 to 26

  • Replaced "base64encodedvalue==" with "BASE64VALUE=" in examples.
  • Minor editorial nits

B.27. 26 to 27

  • Fixed up the 'WG Web' and 'WG List' lines in YANG module(s)
  • Fixed up copyright (i.e., s/Simplified/Revised/) in YANG module(s)
  • Created identityref-based typedefs for each of the four IANA alg identity bases.
  • Added ietf-ssh-common:generate-asymmetric-key-pair() RPC for discussion.

B.28. 27 to 28

  • Fixed example to not have line-returns around "identity" values.
  • Fixed examples to not include "xmlns:algs".
  • Added an example for the "generate-asymmetric-key-pair" RPC.

B.29. 28 to 29

  • Updated modules to IANA-maintained modules in Appendix A to 2022-06-16.

B.30. 29 to 30

  • Fixed 'must' expressions.
  • Added missing 'revision' statement.

B.31. 30 to 31

  • Updated per Shepherd reviews impacting the suite of drafts.

B.32. 31 to 32

  • Updated per Shepherd reviews impacting the suite of drafts.

B.33. 32 to 33

  • Updated per Tom Petch review.
  • Updated Intro to clarify what "generic" means.
  • Added RPC-reply for 'generate-asymmetric-key-pair' example.
  • Added references to RFC 4251 and FIPS 186-6.
  • Added "if-feature ct:encrypted-private-keys" for "case cleartext".

B.34. 33 to 34

  • Addresses AD review comments.
  • Added note to Editor to fix line foldings.
  • Introduction now more clearly identifies the "ietf-" and "iana-" modules defined.
  • Clarified that the modules, when implemented, do not define any protocol-accessible nodes.
  • Clarified that IANA may deprecate and/or obsolete identities over time.
  • Added Security Consideration for the "generate-asymmetric-key-pair" RPC.
  • Added Security Considerations text to also look a SC-section from imported modules.
  • Fixed private-key "must" expressions to not require public-key nodes to be present.
  • Renamed leaf from "bits" to "num-bits".
  • Renamed leaf from "hide" to "hidden".
  • Added container "private-key-encoding" to wrap existing choice.
  • Removed "public-key-format" and "public-key" nodes from examples.

B.35. 34 to 35

  • Addresses AD review by Rob Wilton.

B.36. 35 to 36

  • Addresses 1st-round of IESG reviews.

B.37. 36 to 37

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

Acknowledgements

The authors would like to thank for following for lively discussions on list and in the halls (ordered by first name): Alan Luchuk, Andy Bierman, Balázs Kovács, Barry Leiba, Benoit Claise, Bert Wijnen, David Lamparter, Gary Wu, Jürgen Schönwälder, Ladislav Lhotka, Liang Xia, Martin Björklund, Martin Thomson, Mehmet Ersue, Michal Vaško, Per Andersson, Phil Shafer, Qin Wun, Radek Krejci, Rob Wilton, Sean Turner, Tom Petch, and Thomas Martin.

Contributors

Special acknowledgement goes to Gary Wu for his work on the "ietf-ssh-common" module.

Author's Address

Kent Watsen
Watsen Networks