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NETCONF Working Group                                          K. Watsen
Internet-Draft                                           Watsen Networks
Intended status: Standards Track                                   G. Wu
Expires: October 9, 2019                                   Cisco Systems
                                                                  L. Xia
                                                                  Huawei
                                                           April 7, 2019


             YANG Groupings for TLS Clients and TLS Servers
                draft-ietf-netconf-tls-client-server-11

Abstract

   This document defines three YANG modules: the first defines groupings
   for a generic TLS client, the second defines groupings for a generic
   TLS server, and the third defines common identities and groupings
   used by both the client and the server.  It is intended that these
   groupings will be used by applications using the TLS protocol.

Editorial Note (To be removed by RFC Editor)

   This draft contains many 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.

   This document contains references to other drafts in progress, both
   in the Normative References section, as well as in body text
   throughout.  Please update the following references to reflect their
   final RFC assignments:

   o  I-D.ietf-netconf-trust-anchors

   o  I-D.ietf-netconf-keystore

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

   o  "XXXX" --> the assigned RFC value for this draft

   o  "YYYY" --> the assigned RFC value for I-D.ietf-netconf-trust-
      anchors

   o  "ZZZZ" --> the assigned RFC value for I-D.ietf-netconf-keystore

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



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   o  "2019-04-07" --> the publication date of this draft

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

   o  Appendix A.  Change Log

Status of This Memo

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

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

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

   This Internet-Draft will expire on October 9, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  The TLS Client Model  . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  The TLS Server Model  . . . . . . . . . . . . . . . . . . . .  10
     4.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .  10



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     4.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .  11
     4.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  13
   5.  The TLS Common Model  . . . . . . . . . . . . . . . . . . . .  17
     5.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .  26
     5.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .  26
     5.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  26
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  35
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  36
     7.1.  The IETF XML Registry . . . . . . . . . . . . . . . . . .  36
     7.2.  The YANG Module Names Registry  . . . . . . . . . . . . .  37
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  37
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  37
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  39
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  41
     A.1.  00 to 01  . . . . . . . . . . . . . . . . . . . . . . . .  41
     A.2.  01 to 02  . . . . . . . . . . . . . . . . . . . . . . . .  41
     A.3.  02 to 03  . . . . . . . . . . . . . . . . . . . . . . . .  41
     A.4.  03 to 04  . . . . . . . . . . . . . . . . . . . . . . . .  41
     A.5.  04 to 05  . . . . . . . . . . . . . . . . . . . . . . . .  42
     A.6.  05 to 06  . . . . . . . . . . . . . . . . . . . . . . . .  42
     A.7.  06 to 07  . . . . . . . . . . . . . . . . . . . . . . . .  42
     A.8.  07 to 08  . . . . . . . . . . . . . . . . . . . . . . . .  42
     A.9.  08 to 09  . . . . . . . . . . . . . . . . . . . . . . . .  42
     A.10. 09 to 10  . . . . . . . . . . . . . . . . . . . . . . . .  42
     A.11. 10 to 11  . . . . . . . . . . . . . . . . . . . . . . . .  43
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  43
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  43

1.  Introduction

   This document defines three YANG 1.1 [RFC7950] modules: the first
   defines a grouping for a generic TLS client, the second defines a
   grouping for a generic TLS server, and the third defines identities
   and groupings common to both the client and the server (TLS is
   defined in [RFC5246]).  It is intended that these groupings will be
   used by applications using the TLS protocol.  For instance, these
   groupings could be used to help define the data model for an HTTPS
   [RFC2818] server or a NETCONF over TLS [RFC7589] based server.

   The client and server YANG modules in this document each define one
   grouping, which is focused on just TLS-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 TLS parts it provides, while adding data nodes for
   the TCP-level call-home configuration.



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   The modules defined in this document use groupings defined in
   [I-D.ietf-netconf-keystore] enabling keys to be either locally
   defined or a reference to globally configured values.

2.  Terminology

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

3.  The TLS Client Model

3.1.  Tree Diagram

   This section provides a tree diagram [RFC8340] for the "ietf-tls-
   client" module that does not have groupings expanded.

   =========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========

   module: ietf-tls-client

     grouping tls-client-grouping
       +-- tls-client-parameters
          +-- client-identity
          |  +-- (auth-type)?
          |     +--:(certificate)
          |        +-- certificate
          |           +---u ks:local-or-keystore-end-entity-cert-with-k\
   ey-grouping
          +-- server-authentication
          |  +-- pinned-ca-certs?       ta:pinned-certificates-ref
          |  |       {ta:x509-certificates}?
          |  +-- pinned-server-certs?   ta:pinned-certificates-ref
          |          {ta:x509-certificates}?
          +-- hello-params {tls-client-hello-params-config}?
          |  +---u tlscmn:hello-params-grouping
          +-- keepalives! {tls-client-keepalives}?
             +-- max-wait?       uint16
             +-- max-attempts?   uint8

3.2.  Example Usage

   This section presents two examples showing the tls-client-grouping
   populated with some data.  These examples are effectively the same
   except the first configures the client identity using a local key
   while the second uses a key configured in a keystore.  Both examples



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   are consistent with the examples presented in Section 3 of
   [I-D.ietf-netconf-trust-anchors] and Section 3.2 of
   [I-D.ietf-netconf-keystore].

   The following example configures the client identity using a local
   key:

   =========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========

   <tls-client xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-client">
     <tls-client-parameters>

       <!-- how this client will authenticate itself to the server -->
       <client-identity>
         <certificate>
           <local-definition>
             <algorithm xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-cryp\
   to-types">ct:rsa2048</algorithm>
             <private-key>base64encodedvalue==</private-key>
             <public-key>base64encodedvalue==</public-key>
             <cert>base64encodedvalue==</cert>
           </local-definition>
         </certificate>
       </client-identity>

       <!-- which certificates will this client trust -->
       <server-authentication>
         <pinned-ca-certs>explicitly-trusted-server-ca-certs</pinned-ca\
   -certs>
         <pinned-server-certs>explicitly-trusted-server-certs</pinned-s\
   erver-certs>
       </server-authentication>

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

     </tls-client-parameters>
   </tls-client>

   The following example configures the client identity using a key from
   the keystore:








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   =========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========

   <tls-client xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-client">
     <tls-client-parameters>

       <!-- how this client will authenticate itself to the server -->
       <client-identity>
         <certificate>
           <keystore-reference>ex-rsa-cert</keystore-reference>
         </certificate>
       </client-identity>

       <!-- which certificates will this client trust -->
       <server-authentication>
         <pinned-ca-certs>explicitly-trusted-server-ca-certs</pinned-ca\
   -certs>
         <pinned-server-certs>explicitly-trusted-server-certs</pinned-s\
   erver-certs>
       </server-authentication>

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

     </tls-client-parameters>
   </tls-client>

3.3.  YANG Module

   This YANG module has normative references to
   [I-D.ietf-netconf-trust-anchors] and [I-D.ietf-netconf-keystore].

   <CODE BEGINS> file "ietf-tls-client@2019-04-07.yang"
   module ietf-tls-client {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-tls-client";
     prefix tlsc;

     import ietf-tls-common {
       prefix tlscmn;
       revision-date 2019-04-07; // stable grouping definitions
       reference
         "RFC XXXX: YANG Groupings for TLS Clients and TLS Servers";
     }

     import ietf-trust-anchors {
       prefix ta;



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       reference
         "RFC YYYY: YANG Data Model for Global Trust Anchors";
     }

     import ietf-keystore {
       prefix ks;
       reference
         "RFC ZZZZ: YANG Data Model for a 'Keystore' Mechanism";
     }

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

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

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

     description
       "This module defines reusable groupings for TLS clients that
        can be used as a basis for specific TLS client instances.

        Copyright (c) 2019 IETF Trust and the persons identified
        as authors of the code. All rights reserved.

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

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); 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



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        capitals, as shown here.";

     revision 2019-04-07 {
       description
         "Initial version";
       reference
         "RFC XXXX: YANG Groupings for TLS Clients and TLS Servers";
     }

     // Features

     feature tls-client-hello-params-config {
       description
         "TLS hello message parameters are configurable on a TLS
          client.";
     }

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

     // Groupings

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

       container tls-client-parameters {
         nacm:default-deny-write;

         description
           "A container to hold TLS client configuration.";

         container client-identity {
           description
             "The credentials used by the client to authenticate to
              the TLS server.";
           choice auth-type {
             description
               "The authentication type.";
             container certificate {
               uses
                 ks:local-or-keystore-end-entity-cert-with-key-grouping;
               description



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                 "A locally-defined or referenced certificate
                  to be used for client authentication.";
               reference
                 "RFC ZZZZ: YANG Data Model for a 'Keystore' Mechanism";
             }
           }
         } // container client-identity

         container server-authentication {
           must 'pinned-ca-certs or pinned-server-certs';
           description
             "Trusted server identities.";
           leaf pinned-ca-certs {
             if-feature "ta:x509-certificates";
             type ta:pinned-certificates-ref;
             description
               "A reference to a list of certificate authority (CA)
                certificates used by the TLS client to authenticate
                TLS server certificates.  A server certificate is
                authenticated if it has a valid chain of trust to
                a configured pinned CA certificate.";
           }
           leaf pinned-server-certs {
             if-feature "ta:x509-certificates";
             type ta:pinned-certificates-ref;
             description
               "A reference to a list of server certificates used by
                the TLS client to authenticate TLS server certificates.
                A server certificate is authenticated if it is an
                exact match to a configured pinned server certificate.";
           }
         } // container server-authentication

         container hello-params {
           if-feature "tls-client-hello-params-config";
           uses tlscmn:hello-params-grouping;
           description
             "Configurable parameters for the TLS hello message.";
         } // container hello-params

         container keepalives {
           if-feature "tls-client-keepalives";
           presence "Indicates that keepalives are enabled.";
           description
             "Configures the keep-alive policy, to proactively test
              the aliveness of the TLS server.  An unresponsive
              TLS server is dropped after approximately max-wait
              * max-attempts seconds.";



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           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 TLS server, a
                TLS-level message will be sent to test the
                aliveness of the TLS 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 TLS server before assuming the TLS server is
                no longer alive.";
           }
         } // container keepalives
       } // container tls-client-parameters
     } // grouping tls-client-grouping
   }
   <CODE ENDS>

4.  The TLS Server Model

4.1.  Tree Diagram

   This section provides a tree diagram [RFC8340] for the "ietf-tls-
   server" module that does not have groupings expanded.


















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   =========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========

   module: ietf-tls-server

     grouping tls-server-grouping
       +-- tls-server-parameters
          +-- server-identity
          |  +---u ks:local-or-keystore-end-entity-cert-with-key-groupi\
   ng
          +-- client-authentication
          |  +-- pinned-ca-certs?       ta:pinned-certificates-ref
          |  |       {ta:x509-certificates}?
          |  +-- pinned-client-certs?   ta:pinned-certificates-ref
          |          {ta:x509-certificates}?
          +-- hello-params {tls-server-hello-params-config}?
          |  +---u tlscmn:hello-params-grouping
          +-- keepalives! {tls-server-keepalives}?
             +-- max-wait?       uint16
             +-- max-attempts?   uint8

4.2.  Example Usage

   This section presents two examples showing the tls-server-grouping
   populated with some data.  These examples are effectively the same
   except the first configures the server identity using a local key
   while the second uses a key configured in a keystore.  Both examples
   are consistent with the examples presented in Section 3 of
   [I-D.ietf-netconf-trust-anchors] and Section 3.2 of
   [I-D.ietf-netconf-keystore].

   The following example configures the server identity using a local
   key:



















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   =========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========

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

       <!-- how this server will authenticate itself to the client -->
       <server-identity>
         <local-definition>
           <algorithm xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto\
   -types">ct:rsa2048</algorithm>
           <private-key>base64encodedvalue==</private-key>
           <public-key>base64encodedvalue==</public-key>
           <cert>base64encodedvalue==</cert>
         </local-definition>
       </server-identity>

       <!-- which certificates will this server trust -->
       <client-authentication>
         <pinned-ca-certs>explicitly-trusted-client-ca-certs</pinned-ca\
   -certs>
         <pinned-client-certs>explicitly-trusted-client-certs</pinned-c\
   lient-certs>
       </client-authentication>

     </tls-server-parameters>
   </tls-server>

   The following example configures the server identity using a key from
   the keystore:






















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   =========== NOTE: '\' line wrapping per BCP XX (RFC XXXX) ===========

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

       <!-- how this server will authenticate itself to the client -->
       <server-identity>
         <keystore-reference>ex-rsa-cert</keystore-reference>
       </server-identity>

       <!-- which certificates will this server trust -->
       <client-authentication>
         <pinned-ca-certs>explicitly-trusted-client-ca-certs</pinned-ca\
   -certs>
         <pinned-client-certs>explicitly-trusted-client-certs</pinned-c\
   lient-certs>
       </client-authentication>

     </tls-server-parameters>
   </tls-server>

4.3.  YANG Module

   This YANG module has a normative references to [RFC5246],
   [I-D.ietf-netconf-trust-anchors] and [I-D.ietf-netconf-keystore].

   <CODE BEGINS> file "ietf-tls-server@2019-04-07.yang"
   module ietf-tls-server {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-tls-server";
     prefix tlss;

     import ietf-tls-common {
       prefix tlscmn;
       revision-date 2019-04-07; // stable grouping definitions
       reference
         "RFC XXXX: YANG Groupings for TLS Clients and TLS Servers";
     }

     import ietf-trust-anchors {
       prefix ta;
       reference
         "RFC YYYY: YANG Data Model for Global Trust Anchors";
     }

     import ietf-keystore {
       prefix ks;
       reference



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         "RFC ZZZZ: YANG Data Model for a 'Keystore' Mechanism";
     }

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

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

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

     description
       "This module defines reusable groupings for TLS servers that
        can be used as a basis for specific TLS server instances.

        Copyright (c) 2019 IETF Trust and the persons identified
        as authors of the code. All rights reserved.

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

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); 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 2019-04-07 {
       description
         "Initial version";
       reference
         "RFC XXXX: YANG Groupings for TLS Clients and TLS Servers";



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     }

     // Features

     feature tls-server-hello-params-config {
       description
         "TLS hello message parameters are configurable on a TLS
          server.";
     }

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

     // Groupings

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

       container tls-server-parameters {
         nacm:default-deny-write;

         description
           "A container to hold TLS server configuration.";

         container server-identity {
           description
             "A locally-defined or referenced end-entity certificate,
              including any configured intermediate certificates, the
              TLS server will present when establishing a TLS connection
              in its Certificate message, as defined in Section 7.4.2
              in RFC 5246.";
           reference
             "RFC 5246:
                The Transport Layer Security (TLS) Protocol Version 1.2
              RFC ZZZZ:
                YANG Data Model for a 'Keystore' Mechanism";
           uses ks:local-or-keystore-end-entity-cert-with-key-grouping;
         } // container server-identity

         container client-authentication {
           description
             "A reference to a list of pinned certificate authority (CA)



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              certificates and a reference to a list of pinned client
              certificates.";
           leaf pinned-ca-certs {
             if-feature "ta:x509-certificates";
             type ta:pinned-certificates-ref;
             description
               "A reference to a list of certificate authority (CA)
                certificates used by the TLS server to authenticate
                TLS client certificates.  A client certificate is
                authenticated if it has a valid chain of trust to
                a configured pinned CA certificate.";
             reference
               "RFC YYYY: YANG Data Model for Global Trust Anchors";
           }
           leaf pinned-client-certs {
             if-feature "ta:x509-certificates";
             type ta:pinned-certificates-ref;
             description
               "A reference to a list of client certificates used by
                the TLS server to authenticate TLS client certificates.
                A clients certificate is authenticated if it is an
                exact match to a configured pinned client certificate.";
             reference
               "RFC YYYY: YANG Data Model for Global Trust Anchors";
           }
         } // container client-authentication

         container hello-params {
           if-feature "tls-server-hello-params-config";
           uses tlscmn:hello-params-grouping;
           description
             "Configurable parameters for the TLS hello message.";
         } // container hello-params

         container keepalives {
           if-feature "tls-server-keepalives";
           presence "Indicates that keepalives are enabled.";
           description
             "Configures the keep-alive policy, to proactively test
              the aliveness of the TLS client.  An unresponsive
              TLS client is dropped after approximately max-wait
              * max-attempts seconds.";
           leaf max-wait {
             type uint16 {
               range "1..max";
             }
             units "seconds";
             default "30";



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             description
               "Sets the amount of time in seconds after which if
                no data has been received from the TLS client, a
                TLS-level message will be sent to test the
                aliveness of the TLS 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 TLS client before assuming the TLS client is
                no longer alive.";
           }
         } // container keepalives
       } // container tls-server-parameters
     } // grouping tls-server-grouping
   }
   <CODE ENDS>

5.  The TLS Common Model

   The TLS common model presented in this section contains identities
   and groupings common to both TLS clients and TLS servers.  The hello-
   params-grouping can be used to configure the list of TLS algorithms
   permitted by the TLS client or TLS server.  The lists of algorithms
   are ordered such that, if multiple algorithms are permitted by the
   client, the algorithm that appears first in its list that is also
   permitted by the server is used for the TLS transport layer
   connection.  The ability to restrict the algorithms allowed is
   provided in this grouping for TLS clients and TLS servers that are
   capable of doing so and may serve to make TLS clients and TLS servers
   compliant with local security policies.  This model supports both
   TLS1.2 [RFC5246] and TLS 1.3 [RFC8446].

   TLS 1.2 and TLS 1.3 have different ways defining their own supported
   cryptographic algorithms, see TLS and DTLS IANA registries page
   (https://www.iana.org/assignments/tls-parameters/tls-
   parameters.xhtml):

   o  TLS 1.2 defines four categories of registries for cryptographic
      algorithms: TLS Cipher Suites, TLS SignatureAlgorithm, TLS
      HashAlgorithm, TLS Supported Groups.  TLS Cipher Suites plays the
      role of combining all of them into one set, as each value of the
      set represents a unique and feasible combination of all the
      cryptographic algorithms, and thus the other three registry
      categories do not need to be considered here.  In this document,



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      the TLS common model only chooses those TLS1.2 algorithms in TLS
      Cipher Suites which are marked as recommended:
      TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,
      TLS_DHE_RSA_WITH_AES_256_GCM_SHA384,
      TLS_DHE_PSK_WITH_AES_128_GCM_SHA256,
      TLS_DHE_PSK_WITH_AES_256_GCM_SHA384, and so on.  All chosen
      algorithms are enumerated in Table 1-1 below;

   o  TLS 1.3 defines its supported algorithms differently.  Firstly, it
      defines three categories of registries for cryptographic
      algorithms: TLS Cipher Suites, TLS SignatureScheme, TLS Supported
      Groups.  Secondly, all three of these categories are useful, since
      they represent different parts of all the supported algorithms
      respectively.  Thus, all of these registries categories are
      considered here.  In this draft, the TLS common model chooses only
      those TLS1.3 algorithms specified in B.4, 4.2.3, 4.2.7 of
      [RFC8446].

   Thus, in order to support both TLS1.2 and TLS1.3, the cipher-suites
   part of the hello-params-grouping should include three parameters for
   configuring its permitted TLS algorithms, which are: TLS Cipher
   Suites, TLS SignatureScheme, TLS Supported Groups.  Note that TLS1.2
   only uses TLS Cipher Suites.

   [I-D.ietf-netconf-crypto-types] defines six categories of
   cryptographic algorithms (hash-algorithm, symmetric-key-encryption-
   algorithm, mac-algorithm, asymmetric-key-encryption-algorithm,
   signature-algorithm, key-negotiation-algorithm) and lists several
   widely accepted algorithms for each of them.  The TLS client and
   server models use one or more of these algorithms.  The following
   tables are provided, in part to define the subset of algorithms
   defined in the crypto-types model used by TLS, and in part to ensure
   compatibility of configured TLS cryptographic parameters for
   configuring its permitted TLS algorithms:

















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        +-----------------------------------------------+---------+
        | ciper-suites in hello-params-grouping         |  HASH   |
        +-----------------------------------------------+---------+
        | TLS_DHE_RSA_WITH_AES_128_GCM_SHA256           | sha-256 |
        | TLS_DHE_RSA_WITH_AES_256_GCM_SHA384           | sha-384 |
        | TLS_DHE_PSK_WITH_AES_128_GCM_SHA256           | sha-256 |
        | TLS_DHE_PSK_WITH_AES_256_GCM_SHA384           | sha-384 |
        | TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256       | sha-256 |
        | TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384       | sha-384 |
        | TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256         | sha-256 |
        | TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384         | sha-384 |
        | TLS_DHE_RSA_WITH_AES_128_CCM                  | sha-256 |
        | TLS_DHE_RSA_WITH_AES_256_CCM                  | sha-256 |
        | TLS_DHE_PSK_WITH_AES_128_CCM                  | sha-256 |
        | TLS_DHE_PSK_WITH_AES_256_CCM                  | sha-256 |
        | TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256   | sha-256 |
        | TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 | sha-256 |
        | TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256     | sha-256 |
        | TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256   | sha-256 |
        | TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256     | sha-256 |
        | TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256         | sha-256 |
        | TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384         | sha-384 |
        | TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256         | sha-256 |
        +-----------------------------------------------+---------+

    Table 1-1 TLS 1.2 Compatibility Matrix Part 1: ciper-suites mapping
                             to hash-algorithm
























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  +--------------------------------------------- +---------------------+
  |  ciper-suites in hello-params-grouping       |      symmetric      |
  |                                              |                     |
  +--------------------------------------------- +---------------------+
  | TLS_DHE_RSA_WITH_AES_128_GCM_SHA256          |   enc-aes-128-gcm   |
  | TLS_DHE_RSA_WITH_AES_256_GCM_SHA384          |   enc-aes-256-gcm   |
  | TLS_DHE_PSK_WITH_AES_128_GCM_SHA256          |   enc-aes-128-gcm   |
  | TLS_DHE_PSK_WITH_AES_256_GCM_SHA384          |   enc-aes-256-gcm   |
  | TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256      |   enc-aes-128-gcm   |
  | TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384      |   enc-aes-256-gcm   |
  | TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256        |   enc-aes-128-gcm   |
  | TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384        |   enc-aes-256-gcm   |
  | TLS_DHE_RSA_WITH_AES_128_CCM                 |   enc-aes-128-ccm   |
  | TLS_DHE_RSA_WITH_AES_256_CCM                 |   enc-aes-256-ccm   |
  | TLS_DHE_PSK_WITH_AES_128_CCM                 |   enc-aes-128-ccm   |
  | TLS_DHE_PSK_WITH_AES_256_CCM                 |   enc-aes-256-ccm   |
  | TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256  |enc-chacha20-poly1305|
  | TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256|enc-chacha20-poly1305|
  | TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256    |enc-chacha20-poly1305|
  | TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256  |enc-chacha20-poly1305|
  | TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256    |enc-chacha20-poly1305|
  | TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256        |   enc-aes-128-gcm   |
  | TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384        |   enc-aes-256-gcm   |
  | TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256        |   enc-aes-128-ccm   |
  +--------------------------------------------- +---------------------+

    Table 1-2 TLS 1.2 Compatibility Matrix Part 2: ciper-suites mapping
                   to symmetric-key-encryption-algorithm























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  +--------------------------------------------- +---------------------+
  |  ciper-suites in hello-params-grouping       |         MAC         |
  |                                              |                     |
  +--------------------------------------------- +---------------------+
  | TLS_DHE_RSA_WITH_AES_128_GCM_SHA256          |   mac-aes-128-gcm   |
  | TLS_DHE_RSA_WITH_AES_256_GCM_SHA384          |   mac-aes-256-gcm   |
  | TLS_DHE_PSK_WITH_AES_128_GCM_SHA256          |   mac-aes-128-gcm   |
  | TLS_DHE_PSK_WITH_AES_256_GCM_SHA384          |   mac-aes-256-gcm   |
  | TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256      |   mac-aes-128-gcm   |
  | TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384      |   mac-aes-256-gcm   |
  | TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256        |   mac-aes-128-gcm   |
  | TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384        |   mac-aes-256-gcm   |
  | TLS_DHE_RSA_WITH_AES_128_CCM                 |   mac-aes-128-ccm   |
  | TLS_DHE_RSA_WITH_AES_256_CCM                 |   mac-aes-256-ccm   |
  | TLS_DHE_PSK_WITH_AES_128_CCM                 |   mac-aes-128-ccm   |
  | TLS_DHE_PSK_WITH_AES_256_CCM                 |   mac-aes-256-ccm   |
  | TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256  |mac-chacha20-poly1305|
  | TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256|mac-chacha20-poly1305|
  | TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256    |mac-chacha20-poly1305|
  | TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256  |mac-chacha20-poly1305|
  | TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256    |mac-chacha20-poly1305|
  | TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256        |   mac-aes-128-gcm   |
  | TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384        |   mac-aes-256-gcm   |
  | TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256        |   mac-aes-128-ccm   |
  +--------------------------------------------- +---------------------+

    Table 1-3 TLS 1.2 Compatibility Matrix Part 3: ciper-suites mapping
                             to MAC-algorithm























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 +----------------------------------------------+----------------------+
 |ciper-suites in hello-params-grouping         |        signature     |
 +--------------------------------------------- +----------------------+
 | TLS_DHE_RSA_WITH_AES_128_GCM_SHA256          | rsa-pkcs1-sha256     |
 | TLS_DHE_RSA_WITH_AES_256_GCM_SHA384          | rsa-pkcs1-sha384     |
 | TLS_DHE_PSK_WITH_AES_128_GCM_SHA256          |         N/A          |
 | TLS_DHE_PSK_WITH_AES_256_GCM_SHA384          |         N/A          |
 | TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256      |ecdsa-secp256r1-sha256|
 | TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384      |ecdsa-secp384r1-sha384|
 | TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256        | rsa-pkcs1-sha256     |
 | TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384        | rsa-pkcs1-sha384     |
 | TLS_DHE_RSA_WITH_AES_128_CCM                 | rsa-pkcs1-sha256     |
 | TLS_DHE_RSA_WITH_AES_256_CCM                 | rsa-pkcs1-sha256     |
 | TLS_DHE_PSK_WITH_AES_128_CCM                 |         N/A          |
 | TLS_DHE_PSK_WITH_AES_256_CCM                 |         N/A          |
 | TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256  | rsa-pkcs1-sha256     |
 | TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256|ecdsa-secp256r1-sha256|
 | TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256    | rsa-pkcs1-sha256     |
 | TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256  |         N/A          |
 | TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256    |         N/A          |
 | TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256        |         N/A          |
 | TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384        |         N/A          |
 | TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256        |         N/A          |
 +----------------------------------------------+----------------------+

    Table 1-4 TLS 1.2 Compatibility Matrix Part 4: ciper-suites mapping
                          to signature-algorithm
























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+----------------------------------------------+-----------------------+
|ciper-suites in hello-params-grouping         |     key-negotiation   |
+----------------------------------------------+-----------------------+
| TLS_DHE_RSA_WITH_AES_128_GCM_SHA256          | dhe-ffdhe2048, ...    |
| TLS_DHE_RSA_WITH_AES_256_GCM_SHA384          | dhe-ffdhe2048, ...    |
| TLS_DHE_PSK_WITH_AES_128_GCM_SHA256          | psk-dhe-ffdhe2048, ...|
| TLS_DHE_PSK_WITH_AES_256_GCM_SHA384          | psk-dhe-ffdhe2048, ...|
| TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256      | ecdhe-secp256r1, ...  |
| TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384      | ecdhe-secp256r1, ...  |
| TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256        | ecdhe-secp256r1, ...  |
| TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384        | ecdhe-secp256r1, ...  |
| TLS_DHE_RSA_WITH_AES_128_CCM                 | dhe-ffdhe2048, ...    |
| TLS_DHE_RSA_WITH_AES_256_CCM                 | dhe-ffdhe2048, ...    |
| TLS_DHE_PSK_WITH_AES_128_CCM                 | psk-dhe-ffdhe2048, ...|
| TLS_DHE_PSK_WITH_AES_256_CCM                 | psk-dhe-ffdhe2048, ...|
| TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256  | ecdhe-secp256r1, ...  |
| TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256| ecdhe-secp256r1, ...  |
| TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256    | dhe-ffdhe2048, ...    |
| TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256  |psk-ecdhe-secp256r1,...|
| TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256    | psk-dhe-ffdhe2048, ...|
| TLS_ECDHE_PSK_WITH_AES_128_GCM_SHA256        |psk-ecdhe-secp256r1,...|
| TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384        |psk-ecdhe-secp256r1,...|
| TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256        |psk-ecdhe-secp256r1,...|
+----------------------------------------------+-----------------------+

    Table 1-5 TLS 1.2 Compatibility Matrix Part 5: ciper-suites mapping
                       to key-negotiation-algorithm

                +------------------------------+---------+
                |    ciper-suites in hello     |   HASH  |
                |      -params-grouping        |         |
                +------------------------------+---------+
                | TLS_AES_128_GCM_SHA256       | sha-256 |
                | TLS_AES_256_GCM_SHA384       | sha-384 |
                | TLS_CHACHA20_POLY1305_SHA256 | sha-256 |
                | TLS_AES_128_CCM_SHA256       | sha-256 |
                +------------------------------+---------+

    Table 2-1 TLS 1.3 Compatibility Matrix Part 1: ciper-suites mapping
                             to hash-algorithm











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         +------------------------------+-----------------------+
         |    ciper-suites in hello     |    symmetric          |
         |      -params-grouping        |                       |
         +------------------------------+-----------------------+
         | TLS_AES_128_GCM_SHA256       | enc-aes-128-gcm       |
         | TLS_AES_256_GCM_SHA384       | enc-aes-128-gcm       |
         | TLS_CHACHA20_POLY1305_SHA256 | enc-chacha20-poly1305 |
         | TLS_AES_128_CCM_SHA256       | enc-aes-128-ccm       |
         +------------------------------+-----------------------+

    Table 2-2 TLS 1.3 Compatibility Matrix Part 2: ciper-suites mapping
                  to symmetric-key--encryption-algorithm

         +------------------------------+-----------------------+
         |    ciper-suites in hello     |    symmetric          |
         |      -params-grouping        |                       |
         +------------------------------+-----------------------+
         | TLS_AES_128_GCM_SHA256       | mac-aes-128-gcm       |
         | TLS_AES_256_GCM_SHA384       | mac-aes-128-gcm       |
         | TLS_CHACHA20_POLY1305_SHA256 | mac-chacha20-poly1305 |
         | TLS_AES_128_CCM_SHA256       | mac-aes-128-ccm       |
         +------------------------------+-----------------------+

    Table 2-3 TLS 1.3 Compatibility Matrix Part 3: ciper-suites mapping
                             to MAC-algorithm

         +----------------------------+-------------------------+
         |signatureScheme in hello    |  signature              |
         |   -params-grouping         |                         |
         +----------------------------+-------------------------+
         | rsa-pkcs1-sha256           |  rsa-pkcs1-sha256       |
         | rsa-pkcs1-sha384           |  rsa-pkcs1-sha384       |
         | rsa-pkcs1-sha512           |  rsa-pkcs1-sha512       |
         | rsa-pss-rsae-sha256        |  rsa-pss-rsae-sha256    |
         | rsa-pss-rsae-sha384        |  rsa-pss-rsae-sha384    |
         | rsa-pss-rsae-sha512        |  rsa-pss-rsae-sha512    |
         | rsa-pss-pss-sha256         |  rsa-pss-pss-sha256     |
         | rsa-pss-pss-sha384         |  rsa-pss-pss-sha384     |
         | rsa-pss-pss-sha512         |  rsa-pss-pss-sha512     |
         | ecdsa-secp256r1-sha256     |  ecdsa-secp256r1-sha256 |
         | ecdsa-secp384r1-sha384     |  ecdsa-secp384r1-sha384 |
         | ecdsa-secp521r1-sha512     |  ecdsa-secp521r1-sha512 |
         | ed25519                    |  ed25519                |
         | ed448                      |  ed448                  |
         +----------------------------+-------------------------+

      Table 2-4 TLS 1.3 Compatibility Matrix Part 4: SignatureScheme
                      mapping to signature-algorithm



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         +----------------------------+-------------------------+
         |supported Groups in hello   |     key-negotiation     |
         |   -params-grouping         |                         |
         +----------------------------+-------------------------+
         | dhe-ffdhe2048              | dhe-ffdhe2048           |
         | dhe-ffdhe3072              | dhe-ffdhe3072           |
         | dhe-ffdhe4096              | dhe-ffdhe4096           |
         | dhe-ffdhe6144              | dhe-ffdhe6144           |
         | dhe-ffdhe8192              | dhe-ffdhe8192           |
         | psk-dhe-ffdhe2048          | psk-dhe-ffdhe2048       |
         | psk-dhe-ffdhe3072          | psk-dhe-ffdhe3072       |
         | psk-dhe-ffdhe4096          | psk-dhe-ffdhe4096       |
         | psk-dhe-ffdhe6144          | psk-dhe-ffdhe6144       |
         | psk-dhe-ffdhe8192          | psk-dhe-ffdhe8192       |
         | ecdhe-secp256r1            | ecdhe-secp256r1         |
         | ecdhe-secp384r1            | ecdhe-secp384r1         |
         | ecdhe-secp521r1            | ecdhe-secp521r1         |
         | ecdhe-x25519               | ecdhe-x25519            |
         | ecdhe-x448                 | ecdhe-x448              |
         | psk-ecdhe-secp256r1        | psk-ecdhe-secp256r1     |
         | psk-ecdhe-secp384r1        | psk-ecdhe-secp384r1     |
         | psk-ecdhe-secp521r1        | psk-ecdhe-secp521r1     |
         | psk-ecdhe-x25519           | psk-ecdhe-x25519        |
         | psk-ecdhe-x448             | psk-ecdhe-x448          |
         +----------------------------+-------------------------+

      Table 2-5 TLS 1.3 Compatibility Matrix Part 5: Supported Groups
                   mapping to key-negotiation-algorithm

   Note that in Table 1-5:

   o  dhe-ffdhe2048, ... is the abbreviation of dhe-ffdhe2048, dhe-
      ffdhe3072, dhe-ffdhe4096, dhe-ffdhe6144, dhe-ffdhe8192;

   o  psk-dhe-ffdhe2048, ... is the abbreviation of psk-dhe-ffdhe2048,
      psk-dhe-ffdhe3072, psk-dhe-ffdhe4096, psk-dhe-ffdhe6144, psk-dhe-
      ffdhe8192;

   o  ecdhe-secp256r1, ... is the abbreviation of ecdhe-secp256r1,
      ecdhe-secp384r1, ecdhe-secp521r1, ecdhe-x25519, ecdhe-x448;

   o  psk-ecdhe-secp256r1, ... is the abbreviation of psk-ecdhe-
      secp256r1, psk-ecdhe-secp384r1, psk-ecdhe-secp521r1, psk-ecdhe-
      x25519, psk-ecdhe-x448.

   Features are defined for algorithms that are OPTIONAL or are not
   widely supported by popular implementations.  Note that the list of
   algorithms is not exhaustive.



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5.1.  Tree Diagram

   The following tree diagram [RFC8340] provides an overview of the data
   model for the "ietf-tls-common" module.

   module: ietf-tls-common

     grouping hello-params-grouping
       +-- tls-versions
       |  +-- tls-version*   identityref
       +-- cipher-suites
          +-- cipher-suite*   identityref

5.2.  Example Usage

   This section shows how it would appear if the transport-params-
   grouping were populated with some data.

   <hello-params
      xmlns="urn:ietf:params:xml:ns:yang:ietf-tls-common"
      xmlns:tlscmn="urn:ietf:params:xml:ns:yang:ietf-tls-common">
     <tls-versions>
       <tls-version>tlscmn:tls-1.1</tls-version>
       <tls-version>tlscmn:tls-1.2</tls-version>
     </tls-versions>
     <cipher-suites>
       <cipher-suite>tlscmn:dhe-rsa-with-aes-128-cbc-sha</cipher-suite>
       <cipher-suite>tlscmn:rsa-with-aes-128-cbc-sha</cipher-suite>
       <cipher-suite>tlscmn:rsa-with-3des-ede-cbc-sha</cipher-suite>
     </cipher-suites>
   </hello-params>

5.3.  YANG Module

   This YANG module has a normative references to [RFC4346], [RFC5246],
   [RFC5288], [RFC5289], and [RFC8422].

   This YANG module has a informative references to [RFC2246],
   [RFC4346], [RFC5246], and [RFC8446].

   <CODE BEGINS> file "ietf-tls-common@2019-04-07.yang"
   module ietf-tls-common {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-tls-common";
     prefix tlscmn;

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



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     contact
       "WG Web:   <http://datatracker.ietf.org/wg/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, identities, and
        groupings for Transport Layer Security (TLS).

        Copyright (c) 2019 IETF Trust and the persons identified
        as authors of the code. All rights reserved.

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

        This version of this YANG module is part of RFC XXXX
        (https://www.rfc-editor.org/info/rfcXXXX); 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 2019-04-07 {
       description
         "Initial version";
       reference
         "RFC XXXX: YANG Groupings for TLS Clients and TLS Servers";
     }

     // Features

     feature tls-1_0 {
       description
         "TLS Protocol Version 1.0 is supported.";
       reference
         "RFC 2246: The TLS Protocol Version 1.0";
     }

     feature tls-1_1 {



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       description
         "TLS Protocol Version 1.1 is supported.";
       reference
         "RFC 4346: The Transport Layer Security (TLS) Protocol
                    Version 1.1";
     }

     feature tls-1_2 {
       description
         "TLS Protocol Version 1.2 is supported.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     feature tls-1_3 {
       description
         "TLS Protocol Version 1.2 is supported.";
       reference
         "RFC 8446: The Transport Layer Security (TLS) Protocol
                    Version 1.3";
     }

     feature tls-ecc {
       description
         "Elliptic Curve Cryptography (ECC) is supported for TLS.";
       reference
         "RFC 8422: Elliptic Curve Cryptography (ECC) Cipher Suites
                    for Transport Layer Security (TLS)";
     }

     feature tls-dhe {
       description
         "Ephemeral Diffie-Hellman key exchange is supported for TLS.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     feature tls-3des {
       description
         "The Triple-DES block cipher is supported for TLS.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     feature tls-gcm {



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       description
         "The Galois/Counter Mode authenticated encryption mode is
          supported for TLS.";
       reference
         "RFC 5288: AES Galois Counter Mode (GCM) Cipher Suites for
                    TLS";
     }

     feature tls-sha2 {
       description
         "The SHA2 family of cryptographic hash functions is supported
          for TLS.";
       reference
         "FIPS PUB 180-4: Secure Hash Standard (SHS)";
     }

     // Identities

     identity tls-version-base {
       description
         "Base identity used to identify TLS protocol versions.";
     }

     identity tls-1.0 {
       base tls-version-base;
       if-feature "tls-1_0";
       description
         "TLS Protocol Version 1.0.";
       reference
         "RFC 2246: The TLS Protocol Version 1.0";
     }

     identity tls-1.1 {
       base tls-version-base;
       if-feature "tls-1_1";
       description
         "TLS Protocol Version 1.1.";
       reference
         "RFC 4346: The Transport Layer Security (TLS) Protocol
                    Version 1.1";
     }

     identity tls-1.2 {
       base tls-version-base;
       if-feature "tls-1_2";
       description
         "TLS Protocol Version 1.2.";
       reference



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         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity cipher-suite-base {
       description
         "Base identity used to identify TLS cipher suites.";
     }

     identity rsa-with-aes-128-cbc-sha {
       base cipher-suite-base;
       description
         "Cipher suite TLS_RSA_WITH_AES_128_CBC_SHA.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity rsa-with-aes-256-cbc-sha {
       base cipher-suite-base;
       description
         "Cipher suite TLS_RSA_WITH_AES_256_CBC_SHA.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity rsa-with-aes-128-cbc-sha256 {
       base cipher-suite-base;
       if-feature "tls-sha2";
       description
         "Cipher suite TLS_RSA_WITH_AES_128_CBC_SHA256.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity rsa-with-aes-256-cbc-sha256 {
       base cipher-suite-base;
       if-feature "tls-sha2";
       description
         "Cipher suite TLS_RSA_WITH_AES_256_CBC_SHA256.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity dhe-rsa-with-aes-128-cbc-sha {



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       base cipher-suite-base;
       if-feature "tls-dhe";
       description
         "Cipher suite TLS_DHE_RSA_WITH_AES_128_CBC_SHA.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity dhe-rsa-with-aes-256-cbc-sha {
       base cipher-suite-base;
       if-feature "tls-dhe";
       description
         "Cipher suite TLS_DHE_RSA_WITH_AES_256_CBC_SHA.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity dhe-rsa-with-aes-128-cbc-sha256 {
       base cipher-suite-base;
       if-feature "tls-dhe and tls-sha2";
       description
         "Cipher suite TLS_DHE_RSA_WITH_AES_128_CBC_SHA256.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity dhe-rsa-with-aes-256-cbc-sha256 {
       base cipher-suite-base;
       if-feature "tls-dhe and tls-sha2";
       description
         "Cipher suite TLS_DHE_RSA_WITH_AES_256_CBC_SHA256.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity ecdhe-ecdsa-with-aes-128-cbc-sha256 {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-sha2";
       description
         "Cipher suite TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256.";
       reference
         "RFC 5289: TLS Elliptic Curve Cipher Suites with
                    SHA-256/384 and AES Galois Counter Mode (GCM)";
     }



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     identity ecdhe-ecdsa-with-aes-256-cbc-sha384 {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-sha2";
       description
         "Cipher suite TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384.";
       reference
         "RFC 5289: TLS Elliptic Curve Cipher Suites with
                    SHA-256/384 and AES Galois Counter Mode (GCM)";
     }

     identity ecdhe-rsa-with-aes-128-cbc-sha256 {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-sha2";
       description
         "Cipher suite TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256.";
       reference
         "RFC 5289: TLS Elliptic Curve Cipher Suites with
                    SHA-256/384 and AES Galois Counter Mode (GCM)";
     }

     identity ecdhe-rsa-with-aes-256-cbc-sha384 {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-sha2";
       description
         "Cipher suite TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384.";
       reference
         "RFC 5289: TLS Elliptic Curve Cipher Suites with
                    SHA-256/384 and AES Galois Counter Mode (GCM)";
     }

     identity ecdhe-ecdsa-with-aes-128-gcm-sha256 {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-gcm and tls-sha2";
       description
         "Cipher suite TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256.";
       reference
         "RFC 5289: TLS Elliptic Curve Cipher Suites with
                    SHA-256/384 and AES Galois Counter Mode (GCM)";
     }

     identity ecdhe-ecdsa-with-aes-256-gcm-sha384 {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-gcm and tls-sha2";
       description
         "Cipher suite TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384.";
       reference
         "RFC 5289: TLS Elliptic Curve Cipher Suites with
                    SHA-256/384 and AES Galois Counter Mode (GCM)";



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     }

     identity ecdhe-rsa-with-aes-128-gcm-sha256 {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-gcm and tls-sha2";
       description
         "Cipher suite TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256.";
       reference
         "RFC 5289: TLS Elliptic Curve Cipher Suites with
                    SHA-256/384 and AES Galois Counter Mode (GCM)";
     }

     identity ecdhe-rsa-with-aes-256-gcm-sha384 {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-gcm and tls-sha2";
       description
         "Cipher suite TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384.";
       reference
         "RFC 5289: TLS Elliptic Curve Cipher Suites with
                    SHA-256/384 and AES Galois Counter Mode (GCM)";
     }

     identity rsa-with-3des-ede-cbc-sha {
       base cipher-suite-base;
       if-feature "tls-3des";
       description
         "Cipher suite TLS_RSA_WITH_3DES_EDE_CBC_SHA.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
     }

     identity ecdhe-rsa-with-3des-ede-cbc-sha {
       base cipher-suite-base;
       if-feature "tls-ecc and tls-3des";
       description
         "Cipher suite TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA.";
       reference
         "RFC 8422: Elliptic Curve Cryptography (ECC) Cipher Suites
                    for Transport Layer Security (TLS)";
     }

     identity ecdhe-rsa-with-aes-128-cbc-sha {
       base cipher-suite-base;
       if-feature "tls-ecc";
       description
         "Cipher suite TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA.";
       reference



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         "RFC 8422: Elliptic Curve Cryptography (ECC) Cipher Suites
                    for Transport Layer Security (TLS)";
     }

     identity ecdhe-rsa-with-aes-256-cbc-sha {
       base cipher-suite-base;
       if-feature "tls-ecc";
       description
         "Cipher suite TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA.";
       reference
         "RFC 8422: Elliptic Curve Cryptography (ECC) Cipher Suites
                    for Transport Layer Security (TLS)";
     }

     // Groupings

     grouping hello-params-grouping {
       description
         "A reusable grouping for TLS hello message parameters.";
       reference
         "RFC 5246: The Transport Layer Security (TLS) Protocol
                    Version 1.2";
       container tls-versions {
         description
           "Parameters regarding TLS versions.";
         leaf-list tls-version {
           type identityref {
             base tls-version-base;
           }
           description
             "Acceptable TLS protocol versions.

              If this leaf-list is not configured (has zero elements)
              the acceptable TLS protocol versions are implementation-
              defined.";
         }
       }
       container cipher-suites {
         description
           "Parameters regarding cipher suites.";
         leaf-list cipher-suite {
           type identityref {
             base cipher-suite-base;
           }
           ordered-by user;
           description
             "Acceptable cipher suites in order of descending
              preference.  The configured host key algorithms should



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              be compatible with the algorithm used by the configured
              private key.  Please see Section 5 of RFC XXXX for
              valid combinations.

              If this leaf-list is not configured (has zero elements)
              the acceptable cipher suites are implementation-
              defined.";
           reference
             "RFC XXXX: YANG Groupings for TLS Clients and TLS Servers";
         }
       }
     }
   }
   <CODE ENDS>

6.  Security Considerations

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

   Since the modules in this document only define groupings, these
   considerations are primarily for the designers of other modules that
   use these groupings.

   There are a number of data nodes defined in the YANG modules that are
   writable/creatable/deletable (i.e., config true, which is the
   default).  These data nodes may be considered sensitive or vulnerable
   in some network environments.  Write operations (e.g., edit-config)
   to these data nodes without proper protection can have a negative
   effect on network operations.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

      *: The entire subtree defined by the grouping statement in both
         the "ietf-ssh-client" and "ietf-ssh-server" modules is
         sensitive to write operations.  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, this node is protected the NACM
         extension "default-deny-write".




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   Some of the readable data nodes in the YANG modules may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

      /tls-client-parameters/client-identity/:  This subtree in the
         "ietf-tls-client" module contains nodes that are additionally
         sensitive to read operations such that, in normal use cases,
         they should never be returned to a client.  Some of these nodes
         (i.e., public-key/local-definition/private-key and certificate/
         local-definition/private-key) are already protected by the NACM
         extension "default-deny-all" set in the "grouping" statements
         defined in [I-D.ietf-netconf-crypto-types].

      /tls-server-parameters/server-identity/:  This subtree in the
         "ietf-tls-server" module contains nodes that are additionally
         sensitive to read operations such that, in normal use cases,
         they should never be returned to a client.  All of these nodes
         (i.e., host-key/public-key/local-definition/private-key and
         host-key/certificate/local-definition/private-key) are already
         protected by the NACM extension "default-deny-all" set in the
         "grouping" statements defined in
         [I-D.ietf-netconf-crypto-types].

   Some of the operations in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control access to these operations.  These are the
   operations and their sensitivity/vulnerability:

      *: The groupings defined in this document include "action"
         statements that come from groupings defined in
         [I-D.ietf-netconf-crypto-types].  Please consult that document
         for the security considerations of the "action" statements
         defined by the "grouping" statements defined in this document.

7.  IANA Considerations

7.1.  The IETF XML Registry

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








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

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

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

7.2.  The YANG Module Names Registry

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

      name:         ietf-tls-client
      namespace:    urn:ietf:params:xml:ns:yang:ietf-tls-client
      prefix:       tlsc
      reference:    RFC XXXX

      name:         ietf-tls-server
      namespace:    urn:ietf:params:xml:ns:yang:ietf-tls-server
      prefix:       tlss
      reference:    RFC XXXX

      name:         ietf-tls-common
      namespace:    urn:ietf:params:xml:ns:yang:ietf-tls-common
      prefix:       tlscmn
      reference:    RFC XXXX

8.  References

8.1.  Normative References

   [I-D.ietf-netconf-crypto-types]
              Watsen, K. and H. Wang, "Common YANG Data Types for
              Cryptography", draft-ietf-netconf-crypto-types-05 (work in
              progress), March 2019.

   [I-D.ietf-netconf-keystore]
              Watsen, K., "YANG Data Model for a Centralized Keystore
              Mechanism", draft-ietf-netconf-keystore-08 (work in
              progress), March 2019.





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   [I-D.ietf-netconf-trust-anchors]
              Watsen, K., "YANG Data Model for Global Trust Anchors",
              draft-ietf-netconf-trust-anchors-03 (work in progress),
              March 2019.

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

   [RFC5288]  Salowey, J., Choudhury, A., and D. McGrew, "AES Galois
              Counter Mode (GCM) Cipher Suites for TLS", RFC 5288,
              DOI 10.17487/RFC5288, August 2008,
              <https://www.rfc-editor.org/info/rfc5288>.

   [RFC5289]  Rescorla, E., "TLS Elliptic Curve Cipher Suites with SHA-
              256/384 and AES Galois Counter Mode (GCM)", RFC 5289,
              DOI 10.17487/RFC5289, August 2008,
              <https://www.rfc-editor.org/info/rfc5289>.

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

   [RFC7589]  Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
              NETCONF Protocol over Transport Layer Security (TLS) with
              Mutual X.509 Authentication", RFC 7589,
              DOI 10.17487/RFC7589, June 2015,
              <https://www.rfc-editor.org/info/rfc7589>.

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

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

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








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   [RFC8422]  Nir, Y., Josefsson, S., and M. Pegourie-Gonnard, "Elliptic
              Curve Cryptography (ECC) Cipher Suites for Transport Layer
              Security (TLS) Versions 1.2 and Earlier", RFC 8422,
              DOI 10.17487/RFC8422, August 2018,
              <https://www.rfc-editor.org/info/rfc8422>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

8.2.  Informative References

   [RFC2246]  Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
              RFC 2246, DOI 10.17487/RFC2246, January 1999,
              <https://www.rfc-editor.org/info/rfc2246>.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818,
              DOI 10.17487/RFC2818, May 2000,
              <https://www.rfc-editor.org/info/rfc2818>.

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

   [RFC4346]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.1", RFC 4346,
              DOI 10.17487/RFC4346, April 2006,
              <https://www.rfc-editor.org/info/rfc4346>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

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

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

   [RFC8071]  Watsen, K., "NETCONF Call Home and RESTCONF Call Home",
              RFC 8071, DOI 10.17487/RFC8071, February 2017,
              <https://www.rfc-editor.org/info/rfc8071>.





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
















































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Appendix A.  Change Log

A.1.  00 to 01

   o  Noted that '0.0.0.0' and '::' might have special meanings.

   o  Renamed "keychain" to "keystore".

A.2.  01 to 02

   o  Removed the groupings containing transport-level configuration.
      Now modules contain only the transport-independent groupings.

   o  Filled in previously incomplete 'ietf-tls-client' module.

   o  Added cipher suites for various algorithms into new 'ietf-tls-
      common' module.

A.3.  02 to 03

   o  Added a 'must' statement to container 'server-auth' asserting that
      at least one of the various auth mechanisms must be specified.

   o  Fixed description statement for leaf 'trusted-ca-certs'.

A.4.  03 to 04

   o  Updated title to "YANG Groupings for TLS Clients and TLS Servers"

   o  Updated leafref paths to point to new keystore path

   o  Changed the YANG prefix for ietf-tls-common from 'tlscom' to
      'tlscmn'.

   o  Added TLS protocol verions 1.0 and 1.1.

   o  Made author lists consistent

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

   o  Updated YANG to use typedefs around leafrefs to common keystore
      paths

   o  Now inlines key and certificates (no longer a leafref to keystore)







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A.5.  04 to 05

   o  Merged changes from co-author.

A.6.  05 to 06

   o  Updated to use trust anchors from trust-anchors draft (was
      keystore draft)

   o  Now Uses new keystore grouping enabling asymmetric key to be
      either locally defined or a reference to the keystore.

A.7.  06 to 07

   o  factored the tls-[client|server]-groupings into more reusable
      groupings.

   o  added if-feature statements for the new "x509-certificates"
      feature defined in draft-ietf-netconf-trust-anchors.

A.8.  07 to 08

   o  Added a number of compatibility matrices to Section 5 (thanks
      Frank!)

   o  Clarified that any configured "cipher-suite" values need to be
      compatible with the configured private key.

A.9.  08 to 09

   o  Updated examples to reflect update to groupings defined in the
      keystore draft.

   o  Add TLS keepalives features and groupings.

   o  Prefixed top-level TLS grouping nodes with 'tls-' and support
      mashups.

   o  Updated copyright date, boilerplate template, affiliation, and
      folding algorithm.

A.10.  09 to 10

   o  Reformatted the YANG modules.







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A.11.  10 to 11

   o  Collapsed all the inner groupings into the top-level grouping.

   o  Added a top-level "demux container" inside the top-level grouping.

   o  Added NACM statements and updated the Security Considerations
      section.

   o  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.

   o  Updated the boilerplate text in module-level "description"
      statement to match copyeditor convention.

Acknowledgements

   The authors would like to thank for following for lively discussions
   on list and in the halls (ordered by last name): Andy Bierman, Martin
   Bjorklund, Benoit Claise, Mehmet Ersue, Balazs Kovacs, David
   Lamparter, Alan Luchuk, Ladislav Lhotka, Radek Krejci, Tom Petch,
   Juergen Schoenwaelder, Phil Shafer, Sean Turner, and Bert Wijnen.

Authors' Addresses

   Kent Watsen
   Watsen Networks

   EMail: kent+ietf@watsen.net


   Gary Wu
   Cisco Systems

   EMail: garywu@cisco.com


   Liang Xia
   Huawei

   EMail: frank.xialiang@huawei.com








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