NETCONF Working Group                                          K. Watsen
Internet-Draft                                           Watsen Networks
Intended status: Standards Track                        10 February 2021
Expires: 14 August 2021


             YANG Data Types and Groupings for Cryptography
                   draft-ietf-netconf-crypto-types-19

Abstract

   This document presents a YANG 1.1 (RFC 7950) module defining
   identities, typedefs, and groupings useful to cryptographic
   applications.

Editorial Note (To be removed by RFC Editor)

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

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

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

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

   *  "2021-02-10" --> the publication date of this draft

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

   *  Appendix A.  Change Log

Status of This Memo

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

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






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   Internet-Drafts are draft documents valid for a maximum of six months
   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 14 August 2021.

Copyright Notice

   Copyright (c) 2021 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
     1.1.  Relation to other RFCs  . . . . . . . . . . . . . . . . .   3
     1.2.  Specification Language  . . . . . . . . . . . . . . . . .   5
     1.3.  Adherence to the NMDA . . . . . . . . . . . . . . . . . .   5
   2.  The "ietf-crypto-types" Module  . . . . . . . . . . . . . . .   5
     2.1.  Data Model Overview . . . . . . . . . . . . . . . . . . .   5
     2.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .  18
     2.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  27
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .  47
     3.1.  No Support for CRMF . . . . . . . . . . . . . . . . . . .  48
     3.2.  No Support for Key Generation . . . . . . . . . . . . . .  48
     3.3.  Unconstrained Public Key Usage  . . . . . . . . . . . . .  48
     3.4.  Unconstrained Private Key Usage . . . . . . . . . . . . .  48
     3.5.  Strength of Keys Configured . . . . . . . . . . . . . . .  49
     3.6.  Encrypting Passwords  . . . . . . . . . . . . . . . . . .  49
     3.7.  Deletion of Cleartext Key Values  . . . . . . . . . . . .  49
     3.8.  The "ietf-crypto-types" YANG Module . . . . . . . . . . .  49
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  51
     4.1.  The "IETF XML" Registry . . . . . . . . . . . . . . . . .  51
     4.2.  The "YANG Module Names" Registry  . . . . . . . . . . . .  51
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  51
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .  51
     5.2.  Informative References  . . . . . . . . . . . . . . . . .  53
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  55
     A.1.  I-D to 00 . . . . . . . . . . . . . . . . . . . . . . . .  55



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     A.2.  00 to 01  . . . . . . . . . . . . . . . . . . . . . . . .  55
     A.3.  01 to 02  . . . . . . . . . . . . . . . . . . . . . . . .  56
     A.4.  02 to 03  . . . . . . . . . . . . . . . . . . . . . . . .  56
     A.5.  03 to 04  . . . . . . . . . . . . . . . . . . . . . . . .  57
     A.6.  04 to 05  . . . . . . . . . . . . . . . . . . . . . . . .  57
     A.7.  05 to 06  . . . . . . . . . . . . . . . . . . . . . . . .  57
     A.8.  06 to 07  . . . . . . . . . . . . . . . . . . . . . . . .  58
     A.9.  07 to 08  . . . . . . . . . . . . . . . . . . . . . . . .  58
     A.10. 08 to 09  . . . . . . . . . . . . . . . . . . . . . . . .  58
     A.11. 09 to 10  . . . . . . . . . . . . . . . . . . . . . . . .  58
     A.12. 10 to 11  . . . . . . . . . . . . . . . . . . . . . . . .  59
     A.13. 11 to 12  . . . . . . . . . . . . . . . . . . . . . . . .  59
     A.14. 12 to 13  . . . . . . . . . . . . . . . . . . . . . . . .  59
     A.15. 13 to 14  . . . . . . . . . . . . . . . . . . . . . . . .  59
     A.16. 14 to 15  . . . . . . . . . . . . . . . . . . . . . . . .  60
     A.17. 15 to 16  . . . . . . . . . . . . . . . . . . . . . . . .  60
     A.18. 16 to 17  . . . . . . . . . . . . . . . . . . . . . . . .  60
     A.19. 17 to 18  . . . . . . . . . . . . . . . . . . . . . . . .  61
     A.20. 18 to 19  . . . . . . . . . . . . . . . . . . . . . . . .  61
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  61
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  61

1.  Introduction

   This document presents a YANG 1.1 [RFC7950] module defining
   identities, typedefs, and groupings useful to cryptographic
   applications.

1.1.  Relation to other RFCs

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

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

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







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

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

                       Table 1: Label to RFC Mapping





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1.2.  Specification Language

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

1.3.  Adherence to the NMDA

   This document in compliant with the Network Management Datastore
   Architecture (NMDA) [RFC8342].  It does not define any protocol
   accessible nodes that are "config false".

2.  The "ietf-crypto-types" Module

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

2.1.  Data Model Overview

   This section provides an overview of the "ietf-crypto-types" module
   in terms of its features, indentities, typedefs, and groupings.

2.1.1.  Features

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

   Features:
     +-- one-symmetric-key-format
     +-- one-asymmetric-key-format
     +-- certificate-signing-request-generation
     +-- certificate-expiration-notification
     +-- symmetrically-encrypted-value-format
     +-- asymmetrically-encrypted-value-format
     +-- cms-encrypted-data-format
     +-- cms-enveloped-data-format

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







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2.1.2.  Identities

   The following diagram illustrates the relationship amongst the
   "identity" statements defined in the "ietf-crypto-types" module:

   Identities:
     +-- public-key-format
     |  +-- subject-public-key-info-format
     |  +-- ssh-public-key-format
     +-- private-key-format
     |  +-- rsa-private-key-format
     |  +-- ec-private-key-format
     |  +-- one-asymmetric-key-format
     |            {one-asymmetric-key-format}?
     +-- symmetric-key-format
     |  +-- octet-string-key-format
     |  +-- one-symmetric-key-format
     |            {one-symmetric-key-format}?
     +-- encrypted-value-format
        +-- symmetrically-encrypted-value-format
        |  |      {symmetrically-encrypted-value-format}?
        |  +-- cms-encrypted-data-format
        |         {cms-encrypted-data-format}?
        +-- asymmetrically-encrypted-value-format
           |      {asymmetrically-encrypted-value-format}?
           +-- cms-enveloped-data-format
                  {cms-enveloped-data-format}?

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

   Comments:

   *  The diagram shows that there are four base identities.  The first
      three identities are used to indicate the format that key data,
      while the fourth identity is used to indicate the format for
      encrypted values.  The base identities are "abstract", in the
      object orientied programming sense, in that they only define a
      "class" of formats, rather than a specific format.

   *  The various "leaf" identities define specific encoding formats.
      The derived identities defined in this document are sufficient for
      the effort described in Section 1.1 but, by nature of them being
      identities, additional derived identities MAY be defined by future
      efforts.






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   *  Identities used to specify uncommon formats are enabled by
      "feature" statements, allowing applications to support them when
      needed.

2.1.3.  Typedefs

   The following diagram illustrates the relationship amongst the
   "typedef" statements defined in the "ietf-crypto-types" module:

   Typedefs:
     binary
       +-- csr-info
       +-- csr
       +-- x509
       |  +-- trust-anchor-cert-x509
       |  +-- end-entity-cert-x509
       +-- crl
       +-- ocsp-request
       +-- ocsp-response
       +-- cms
          +-- data-content-cms
          +-- signed-data-cms
          |  +-- trust-anchor-cert-cms
          |  +-- end-entity-cert-cms
          +-- enveloped-data-cms
          +-- digested-data-cms
          +-- encrypted-data-cms
          +-- authenticated-data-cms

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

   Comments:

   *  All of the typedefs defined in the "ietf-crypto-types" module
      extend the "binary" type defined in [RFC7950].

   *  Additionally, all the typedefs define a type for encoding an ASN.1
      [ITU.X680.2015] structure using DER [ITU.X690.2015].

   *  The "trust-anchor-*" and "end-entity-*" typedefs are syntactically
      identical to their base typedefs and only distiguish themselves by
      the expected nature of their content.  These typedefs are defined
      to facilitate common modeling needs.







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2.1.4.  Groupings

   The "ietf-crypto-types" module defines the following "grouping"
   statements:

   *  encrypted-value-grouping
   *  password-grouping
   *  symmetric-key-grouping
   *  public-key-grouping
   *  asymmetric-key-pair-grouping
   *  trust-anchor-cert-grouping
   *  end-entity-cert-grouping
   *  generate-csr-grouping
   *  asymmetric-key-pair-with-cert-grouping
   *  asymmetric-key-pair-with-certs-grouping

   Each of these groupings are presented in the following subsections.

2.1.4.1.  The "encrypted-value-grouping" Grouping

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

     grouping encrypted-value-grouping
       +-- encrypted-by
       +-- encrypted-value-format    identityref
       +-- encrypted-value           binary

   Comments:

   *  The "encrypted-by" node is an empty container (difficult to see in
      the diagram) that a consuming module MUST augment key references
      into.  The "ietf-crypto-types" module is unable to populate this
      container as the module only defines groupings.  Section 2.2.1
      presents an example illustrating a consuming module populating the
      "encrypted-by" container.

   *  The "encrypted-value" node is the value, encrypted by the key
      referenced by the "encrypted-by" node, and encoded in the format
      appropriate for the kind of key it was encrypted by.

      -  If the value is encrypted by a symmetric key, then the
         encrypted value is encoded using the format associated with the
         "symmetrically-encrypted-value-format" identity.

      -  If the value is encrypted by an asymmetric key, then the
         encrypted value is encoded using the format associated with the
         "asymmetrically-encrypted-value-format" identity.



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      See Section 2.1.2 for information about the "format" identities.

2.1.4.2.  The "password-grouping" Grouping

   This section presents two tree diagrams [RFC8340] illustrating the
   "password-grouping" grouping.  The first tree diagram does not expand
   the internally used grouping statement(s):

     grouping password-grouping
       +-- (password-type)
          +--:(cleartext-password)
          |  +-- cleartext-password?   string
          +--:(encrypted-password) {password-encryption}?
             +-- encrypted-password
                +---u encrypted-value-grouping

   The following tree diagram expands the internally used grouping
   statement(s), enabling the grouping's full structure to be seen:

     grouping password-grouping
       +-- (password-type)
          +--:(cleartext-password)
          |  +-- cleartext-password?   string
          +--:(encrypted-password) {password-encryption}?
             +-- encrypted-password
                +-- encrypted-by
                +-- encrypted-value-format    identityref
                +-- encrypted-value           binary

   Comments:

   *  For the referenced grouping statement(s):

      -  The "encrypted-value-grouping" grouping is discussed in
         Section 2.1.4.1.

   *  The "choice" statement enables the password data to be cleartext
      or encrypted, as follows:

      -  The "cleartext-password" node can encode any cleartext value.
      -  The "encrypted-password" node's structure is discussed in
         Section 2.1.4.1.

2.1.4.3.  The "symmetric-key-grouping" Grouping

   This section presents two tree diagrams [RFC8340] illustrating the
   "symmetric-key-grouping" grouping.  The first tree diagram does not
   expand the internally used grouping statement(s):



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     grouping symmetric-key-grouping
       +-- key-format?            identityref
       +-- (key-type)
          +--:(cleartext-key)
          |  +-- cleartext-key?   binary
          +--:(hidden-key)
          |  +-- hidden-key?      empty
          +--:(encrypted-key) {symmetric-key-encryption}?
             +-- encrypted-key
                +---u encrypted-value-grouping

   The following tree diagram expands the internally used grouping
   statement(s), enabling the grouping's full structure to be seen:

     grouping symmetric-key-grouping
       +-- key-format?            identityref
       +-- (key-type)
          +--:(cleartext-key)
          |  +-- cleartext-key?   binary
          +--:(hidden-key)
          |  +-- hidden-key?      empty
          +--:(encrypted-key) {symmetric-key-encryption}?
             +-- encrypted-key
                +-- encrypted-by
                +-- encrypted-value-format    identityref
                +-- encrypted-value           binary

   Comments:

   *  For the referenced grouping statement(s):

      -  The "encrypted-value-grouping" grouping is discussed in
         Section 2.1.4.1.

   *  The "key-format" node is an identity-reference to the "symmetric-
      key-format" abstract base identity discussed in Section 2.1.2,
      enabling the symmetric key to be encoded using the format defined
      by any of the derived identities.

   *  The "choice" statement enables the private key data to be
      cleartext, encrypted, or hidden, as follows:

      -  The "cleartext-key" node can encode any cleartext key value.
      -  The "hidden-key" node is of type "empty" as the real value
         cannot be presented via the management interface.
      -  The "encrypted-key" node's structure is discussed in
         Section 2.1.4.1.




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2.1.4.4.  The "public-key-grouping" Grouping

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

     grouping public-key-grouping
       +-- public-key-format    identityref
       +-- public-key           binary

   Comments:

   *  The "public-key-format" node is an identity-reference to the
      "public-key-format" abstract base identity discussed in
      Section 2.1.2, enabling the public key to be encoded using the
      format defined by any of the derived identities.

   *  The "public-key" node is the public key data in the selected
      format.  No "choice" statement is used to hide or encrypt the
      public key data because it is unecessary to do so for public keys.

2.1.4.5.  The "asymmetric-key-pair-grouping" Grouping

   This section presents two tree diagrams [RFC8340] illustrating the
   "asymmetric-key-pair-grouping" grouping.  The first tree diagram does
   not expand the internally used grouping statement(s):

     grouping asymmetric-key-pair-grouping
       +---u public-key-grouping
       +-- private-key-format?            identityref
       +-- (private-key-type)
          +--:(cleartext-private-key)
          |  +-- cleartext-private-key?   binary
          +--:(hidden-private-key)
          |  +-- hidden-private-key?      empty
          +--:(encrypted-private-key) {private-key-encryption}?
             +-- encrypted-private-key
                +---u encrypted-value-grouping

   The following tree diagram expands the internally used grouping
   statement(s), enabling the grouping's full structure to be seen:











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     grouping asymmetric-key-pair-grouping
       +-- public-key-format              identityref
       +-- public-key                     binary
       +-- private-key-format?            identityref
       +-- (private-key-type)
          +--:(cleartext-private-key)
          |  +-- cleartext-private-key?   binary
          +--:(hidden-private-key)
          |  +-- hidden-private-key?      empty
          +--:(encrypted-private-key) {private-key-encryption}?
             +-- encrypted-private-key
                +-- encrypted-by
                +-- encrypted-value-format    identityref
                +-- encrypted-value           binary

   Comments:

   *  For the referenced grouping statement(s):

      -  The "public-key-grouping" grouping is discussed in
         Section 2.1.4.4.
      -  The "encrypted-value-grouping" grouping is discussed in
         Section 2.1.4.1.

   *  The "private-key-format" node is an identity-reference to the
      "private-key-format" abstract base identity discussed in
      Section 2.1.2, enabling the private key to be encoded using the
      format defined by any of the derived identities.

   *  The "choice" statement enables the private key data to be
      cleartext, encrypted, or hidden, as follows:

      -  The "cleartext-private-key" node can encode any cleartext key
         value.
      -  The "hidden-private-key" node is of type "empty" as the real
         value cannot be presented via the management interface.
      -  The "encrypted-private-key" node's structure is discussed in
         Section 2.1.4.1.

2.1.4.6.  The "certificate-expiration-grouping" Grouping

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

     grouping certificate-expiration-grouping
       +---n certificate-expiration
               {certificate-expiration-notification}?
          +-- expiration-date    yang:date-and-time



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   Comments:

   *  This grouping's only purpose is to define the "certificate-
      expiration" notification statement, used by the groupings defined
      in Section 2.1.4.7 and Section 2.1.4.8.

   *  The "certificate-expiration" notification enables servers to
      notify clients when certificates are nearing expiration.

   *  The "expiration-date" node indicates when the designated
      certificate will (or did) expire.

   *  Identification of the certificate that is expiring is built into
      the notification itself.  For an example, please see
      Section 2.2.3.

2.1.4.7.  The "trust-anchor-cert-grouping" Grouping

   This section presents two tree diagrams [RFC8340] illustrating the
   "trust-anchor-cert-grouping" grouping.  The first tree diagram does
   not expand the internally used grouping statement(s):

     grouping trust-anchor-cert-grouping
       +-- cert-data?                         trust-anchor-cert-cms
       +---u certificate-expiration-grouping

   The following tree diagram expands the internally used grouping
   statement(s), enabling the grouping's full structure to be seen:

     grouping trust-anchor-cert-grouping
       +-- cert-data?                trust-anchor-cert-cms
       +---n certificate-expiration
               {certificate-expiration-notification}?
          +-- expiration-date    yang:date-and-time

   Comments:

   *  For the referenced grouping statement(s):

      -  The "certificate-expiration-grouping" grouping is discussed in
         Section 2.1.4.6.

   *  The "cert-data" node contains a chain of one or more certificates
      encoded using a "signed-data-cms" typedef discussed in
      Section 2.1.3.






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2.1.4.8.  The "end-entity-cert-grouping" Grouping

   This section presents two tree diagrams [RFC8340] illustrating the
   "end-entity-cert-grouping" grouping.  The first tree diagram does not
   expand the internally used grouping statement(s):

     grouping end-entity-cert-grouping
       +-- cert-data?                         end-entity-cert-cms
       +---u certificate-expiration-grouping

   The following tree diagram expands the internally used grouping
   statement(s), enabling the grouping's full structure to be seen:

     grouping end-entity-cert-grouping
       +-- cert-data?                end-entity-cert-cms
       +---n certificate-expiration
               {certificate-expiration-notification}?
          +-- expiration-date    yang:date-and-time

   Comments:

   *  For the referenced grouping statement(s):

      -  The "certificate-expiration-grouping" grouping is discussed in
         Section 2.1.4.6.

   *  The "cert-data" node contains a chain of one or more certificates
      encoded using a "signed-data-cms" typedef discussed in
      Section 2.1.3.

2.1.4.9.  The "generate-csr-grouping" Grouping

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

     grouping generate-csr-grouping
       +---x generate-certificate-signing-request
               {certificate-signing-request-generation}?
          +---w input
          |  +---w csr-info    ct:csr-info
          +--ro output
             +--ro certificate-signing-request    ct:csr

   Comments:

   *  This grouping's only purpose is to define the "generate-
      certificate-signing-request" action statement, used by the
      groupings defined in Section 2.1.4.10 and Section 2.1.4.11.



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   *  This action takes as input a "csr-info" type and returns a "csr"
      type, both of which are discussed in Section 2.1.3.

   *  For an example, please see Section 2.2.2.

2.1.4.10.  The "asymmetric-key-pair-with-cert-grouping" Grouping

   This section presents two tree diagrams [RFC8340] illustrating the
   "asymmetric-key-pair-with-cert-grouping" grouping.  The first tree
   diagram does not expand the internally used grouping statement(s):

     grouping asymmetric-key-pair-with-cert-grouping
       +---u asymmetric-key-pair-grouping
       +---u end-entity-cert-grouping
       +---u generate-csr-grouping

   The following tree diagram expands the internally used grouping
   statement(s), enabling the grouping's full structure to be seen:

     grouping asymmetric-key-pair-with-cert-grouping
       +-- public-key-format                       identityref
       +-- public-key                              binary
       +-- private-key-format?                     identityref
       +-- (private-key-type)
       |  +--:(cleartext-private-key)
       |  |  +-- cleartext-private-key?            binary
       |  +--:(hidden-private-key)
       |  |  +-- hidden-private-key?               empty
       |  +--:(encrypted-private-key) {private-key-encryption}?
       |     +-- encrypted-private-key
       |        +-- encrypted-by
       |        +-- encrypted-value-format    identityref
       |        +-- encrypted-value           binary
       +-- cert-data?                              end-entity-cert-cms
       +---n certificate-expiration
       |       {certificate-expiration-notification}?
       |  +-- expiration-date    yang:date-and-time
       +---x generate-certificate-signing-request
               {certificate-signing-request-generation}?
          +---w input
          |  +---w csr-info    ct:csr-info
          +--ro output
             +--ro certificate-signing-request    ct:csr

   Comments:






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   *  This grouping defines an asymmetric key with at most one
      associated certificate, a commonly needed combination in protocol
      models.

   *  For the referenced grouping statement(s):

      -  The "asymmetric-key-pair-grouping" grouping is discussed in
         Section 2.1.4.5.
      -  The "end-entity-cert-grouping" grouping is discussed in
         Section 2.1.4.8.
      -  The "generate-csr-grouping" grouping is discussed in
         Section 2.1.4.9.

2.1.4.11.  The "asymmetric-key-pair-with-certs-grouping" Grouping

   This section presents two tree diagrams [RFC8340] illustrating the
   "asymmetric-key-pair-with-certs-grouping" grouping.  The first tree
   diagram does not expand the internally used grouping statement(s):

     grouping asymmetric-key-pair-with-certs-grouping
       +---u asymmetric-key-pair-grouping
       +-- certificates
       |  +-- certificate* [name]
       |     +-- name?                       string
       |     +---u end-entity-cert-grouping
       +---u generate-csr-grouping

   The following tree diagram expands the internally used grouping
   statement(s), enabling the grouping's full structure to be seen:






















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     grouping asymmetric-key-pair-with-certs-grouping
       +-- public-key-format                       identityref
       +-- public-key                              binary
       +-- private-key-format?                     identityref
       +-- (private-key-type)
       |  +--:(cleartext-private-key)
       |  |  +-- cleartext-private-key?            binary
       |  +--:(hidden-private-key)
       |  |  +-- hidden-private-key?               empty
       |  +--:(encrypted-private-key) {private-key-encryption}?
       |     +-- encrypted-private-key
       |        +-- encrypted-by
       |        +-- encrypted-value-format    identityref
       |        +-- encrypted-value           binary
       +-- certificates
       |  +-- certificate* [name]
       |     +-- name?                     string
       |     +-- cert-data                 end-entity-cert-cms
       |     +---n certificate-expiration
       |             {certificate-expiration-notification}?
       |        +-- expiration-date    yang:date-and-time
       +---x generate-certificate-signing-request
               {certificate-signing-request-generation}?
          +---w input
          |  +---w csr-info    ct:csr-info
          +--ro output
             +--ro certificate-signing-request    ct:csr

   Comments:

   *  This grouping defines an asymmetric key with one or more
      associated certificates, a commonly needed combination in
      configuration models.

   *  For the referenced grouping statement(s):

      -  The "asymmetric-key-pair-grouping" grouping is discussed in
         Section 2.1.4.5.
      -  The "end-entity-cert-grouping" grouping is discussed in
         Section 2.1.4.8.
      -  The "generate-csr-grouping" grouping is discussed in
         Section 2.1.4.9.









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2.1.5.  Protocol-accessible Nodes

   The "ietf-crypto-types" module does not contain any protocol-
   accessible nodes, but the module needs to be "implemented", as
   described in Section 5.6.5 of [RFC7950], in order for the identities
   in Section 2.1.2 to be defined.

2.2.  Example Usage

2.2.1.  The "symmetric-key-grouping" and "asymmetric-key-pair-with-
        certs-grouping" Grouping

   The following non-normative module is constructed in order to
   illustrate the use of the "symmetric-key-grouping" (Section 2.1.4.3),
   the "asymmetric-key-pair-with-certs-grouping" (Section 2.1.4.11), and
   the "password-grouping" (Section 2.1.4.2) grouping statements.

   Notably, this example illustrates a hidden asymmetric key (ex-hidden-
   asymmetric-key) has been used to encrypt a symmetric key (ex-
   encrypted-one-symmetric-based-symmetric-key) that has been used to
   encrypt another asymmetric key (ex-encrypted-rsa-based-asymmetric-
   key).  Additionally, the symmetric key is also used to encrypt a
   password (ex-encrypted-password).

   module ex-crypto-types-usage {
     yang-version 1.1;

     namespace "http://example.com/ns/example-crypto-types-usage";
     prefix "ectu";

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

     organization "Example Corporation";
     contact      "YANG Designer <mailto:yang.designer@example.com>";

     description
      "This module illustrates the 'symmetric-key-grouping'
       and 'asymmetric-key-grouping' groupings defined in
       the 'ietf-crypto-types' module defined in RFC AAAA.";

     revision "2021-02-10" {
       description
        "Initial version";
       reference



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        "RFC AAAA: Common YANG Data Types for Cryptography";
     }


     container symmetric-keys {
       description
         "A container of symmetric keys.";
       list symmetric-key {
         key name;
         description
           "A symmetric key";
         leaf name {
           type string;
           description
             "An arbitrary name for this key.";
         }
         uses ct:symmetric-key-grouping {
           augment "key-type/encrypted-key/encrypted-key/"
                   + "encrypted-by" {
             description
               "Augments in a choice statement enabling the
                encrypting key to be any other symmetric or
                asymmetric key.";
             uses encrypted-by-choice-grouping;
           }
         }
       }
     }

     container asymmetric-keys {
       description
         "A container of asymmetric keys.";
       list asymmetric-key {
         key name;
         leaf name {
           type string;
           description
             "An arbitrary name for this key.";
         }
         uses ct:asymmetric-key-pair-with-certs-grouping {
           augment "private-key-type/encrypted-private-key/"
                   + "encrypted-private-key/encrypted-by" {
             description
               "Augments in a choice statement enabling the
                encrypting key to be any other symmetric or
                asymmetric key.";
             uses encrypted-by-choice-grouping;
           }



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         }
         description
           "An asymmetric key pair with associated certificates.";
       }
     }

     container passwords {
       description
         "A container of passwords.";
       list password {
         key name;
         leaf name {
           type string;
           description
             "An arbitrary name for this password.";
         }
         uses ct:password-grouping {
           augment "password-type/encrypted-password/"
                   + "encrypted-password/encrypted-by" {
             description
               "Augments in a choice statement enabling the
                encrypting key to be any symmetric or
                asymmetric key.";
             uses encrypted-by-choice-grouping;
           }
         }
         description
           "A password.";
       }
     }


     grouping encrypted-by-choice-grouping {
       description
         "A grouping that defines a choice enabling references
          to other keys.";
       choice encrypted-by-choice {
         mandatory true;
         description
           "A choice amongst other symmetric or asymmetric keys.";
         case symmetric-key-ref {
           leaf symmetric-key-ref {
             type leafref {
               path "/ectu:symmetric-keys/ectu:symmetric-key/"
                    + "ectu:name";
             }
             description
              "Identifies the symmetric key used to encrypt this key.";



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           }
         }
         case asymmetric-key-ref {
           leaf asymmetric-key-ref {
             type leafref {
               path "/ectu:asymmetric-keys/ectu:asymmetric-key/"
                    + "ectu:name";
             }
             description
              "Identifies the asymmetric key used to encrypt this key.";
           }
         }
       }
     }

   }

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

   module: ex-crypto-types-usage
     +--rw symmetric-keys
     |  +--rw symmetric-key* [name]
     |     +--rw name                   string
     |     +--rw key-format?            identityref
     |     +--rw (key-type)
     |        +--:(cleartext-key)
     |        |  +--rw cleartext-key?   binary
     |        +--:(hidden-key)
     |        |  +--rw hidden-key?      empty
     |        +--:(encrypted-key) {symmetric-key-encryption}?
     |           +--rw encrypted-key
     |              +--rw encrypted-by
     |              |  +--rw (encrypted-by-choice)
     |              |     +--:(symmetric-key-ref)
     |              |     |  +--rw symmetric-key-ref?    leafref
     |              |     +--:(asymmetric-key-ref)
     |              |        +--rw asymmetric-key-ref?   leafref
     |              +--rw encrypted-value-format    identityref
     |              +--rw encrypted-value           binary
     +--rw asymmetric-keys
     |  +--rw asymmetric-key* [name]
     |     +--rw name                                    string
     |     +--rw public-key-format                       identityref
     |     +--rw public-key                              binary
     |     +--rw private-key-format?                     identityref
     |     +--rw (private-key-type)
     |     |  +--:(cleartext-private-key)
     |     |  |  +--rw cleartext-private-key?            binary



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     |     |  +--:(hidden-private-key)
     |     |  |  +--rw hidden-private-key?               empty
     |     |  +--:(encrypted-private-key) {private-key-encryption}?
     |     |     +--rw encrypted-private-key
     |     |        +--rw encrypted-by
     |     |        |  +--rw (encrypted-by-choice)
     |     |        |     +--:(symmetric-key-ref)
     |     |        |     |  +--rw symmetric-key-ref?    leafref
     |     |        |     +--:(asymmetric-key-ref)
     |     |        |        +--rw asymmetric-key-ref?   leafref
     |     |        +--rw encrypted-value-format    identityref
     |     |        +--rw encrypted-value           binary
     |     +--rw certificates
     |     |  +--rw certificate* [name]
     |     |     +--rw name                      string
     |     |     +--rw cert-data                 end-entity-cert-cms
     |     |     +---n certificate-expiration
     |     |             {certificate-expiration-notification}?
     |     |        +-- expiration-date    yang:date-and-time
     |     +---x generate-certificate-signing-request
     |             {certificate-signing-request-generation}?
     |        +---w input
     |        |  +---w csr-info    ct:csr-info
     |        +--ro output
     |           +--ro certificate-signing-request    ct:csr
     +--rw passwords
        +--rw password* [name]
           +--rw name                        string
           +--rw (password-type)
              +--:(cleartext-password)
              |  +--rw cleartext-password?   string
              +--:(encrypted-password) {password-encryption}?
                 +--rw encrypted-password
                    +--rw encrypted-by
                    |  +--rw (encrypted-by-choice)
                    |     +--:(symmetric-key-ref)
                    |     |  +--rw symmetric-key-ref?    leafref
                    |     +--:(asymmetric-key-ref)
                    |        +--rw asymmetric-key-ref?   leafref
                    +--rw encrypted-value-format    identityref
                    +--rw encrypted-value           binary

   Finally, the following example illustrates various symmetric and
   asymmetric keys as they might appear in configration:







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

   <symmetric-keys
     xmlns="http://example.com/ns/example-crypto-types-usage"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
     <symmetric-key>
       <name>ex-hidden-symmetric-key</name>
       <hidden-key/>
     </symmetric-key>
     <symmetric-key>
       <name>ex-octet-string-based-symmetric-key</name>
       <key-format>ct:octet-string-key-format</key-format>
       <cleartext-key>base64encodedvalue==</cleartext-key>
     </symmetric-key>
     <symmetric-key>
       <name>ex-one-symmetric-based-symmetric-key</name>
       <key-format>ct:one-symmetric-key-format</key-format>
       <cleartext-key>base64encodedvalue==</cleartext-key>
     </symmetric-key>
     <symmetric-key>
       <name>ex-encrypted-one-symmetric-based-symmetric-key</name>
       <key-format>ct:one-symmetric-key-format</key-format>
       <encrypted-key>
         <encrypted-by>
           <asymmetric-key-ref>ex-hidden-asymmetric-key</asymmetric-key\
   -ref>
         </encrypted-by>
         <encrypted-value-format>
           ct:cms-enveloped-data-format
         </encrypted-value-format>
         <encrypted-value>base64encodedvalue==</encrypted-value>
       </encrypted-key>
     </symmetric-key>
   </symmetric-keys>

   <asymmetric-keys
     xmlns="http://example.com/ns/example-crypto-types-usage"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
     <asymmetric-key>
       <name>ex-hidden-asymmetric-key</name>
       <public-key-format>
         ct:subject-public-key-info-format
       </public-key-format>
       <public-key>base64encodedvalue==</public-key>
       <hidden-private-key/>
       <certificates>
         <certificate>
           <name>ex-hidden-asymmetric-key-cert</name>



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           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificates>
     </asymmetric-key>
     <asymmetric-key>
       <name>ex-rsa-based-asymmetric-key</name>
       <public-key-format>
         ct:subject-public-key-info-format
       </public-key-format>
       <public-key>base64encodedvalue==</public-key>
       <private-key-format>
         ct:rsa-private-key-format
       </private-key-format>
       <cleartext-private-key>base64encodedvalue==</cleartext-private-k\
   ey>
       <certificates>
         <certificate>
           <name>ex-cert</name>
           <cert-data>base64encodedvalue==</cert-data>
         </certificate>
       </certificates>
     </asymmetric-key>
     <asymmetric-key>
       <name>ex-one-asymmetric-based-asymmetric-key</name>
       <public-key-format>
         ct:subject-public-key-info-format
       </public-key-format>
       <public-key>base64encodedvalue==</public-key>
       <private-key-format>
         ct:one-asymmetric-key-format
       </private-key-format>
       <cleartext-private-key>base64encodedvalue==</cleartext-private-k\
   ey>
     </asymmetric-key>
     <asymmetric-key>
       <name>ex-encrypted-rsa-based-asymmetric-key</name>
       <public-key-format>
         ct:subject-public-key-info-format
       </public-key-format>
       <public-key>base64encodedvalue==</public-key>
       <private-key-format>
         ct:rsa-private-key-format
       </private-key-format>
       <encrypted-private-key>
         <encrypted-by>
           <symmetric-key-ref>ex-encrypted-one-symmetric-based-symmetri\
   c-key</symmetric-key-ref>
         </encrypted-by>



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         <encrypted-value-format>
           ct:cms-encrypted-data-format
         </encrypted-value-format>
         <encrypted-value>base64encodedvalue==</encrypted-value>
       </encrypted-private-key>
     </asymmetric-key>
   </asymmetric-keys>

   <passwords
     xmlns="http://example.com/ns/example-crypto-types-usage"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
     <password>
       <name>ex-cleartext-password</name>
       <cleartext-password>super-secret</cleartext-password>
     </password>
     <password>
       <name>ex-encrypted-password</name>
       <encrypted-password>
         <encrypted-by>
           <symmetric-key-ref>ex-encrypted-one-symmetric-based-symmetri\
   c-key</symmetric-key-ref>
         </encrypted-by>
         <encrypted-value-format>
           ct:cms-encrypted-data-format
         </encrypted-value-format>
         <encrypted-value>base64encodedvalue==</encrypted-value>
       </encrypted-password>
     </password>
   </passwords>

2.2.2.  The "generate-certificate-signing-request" Action

   The following example illustrates the "generate-certificate-signing-
   request" action, discussed in Section 2.1.4.9, with the NETCONF
   protocol.

   REQUEST














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   <rpc message-id="101"
     xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
     <action xmlns="urn:ietf:params:xml:ns:yang:1">
       <asymmetric-keys
         xmlns="http://example.com/ns/example-crypto-types-usage">
         <asymmetric-key>
           <name>ex-key-sect571r1</name>
           <generate-certificate-signing-request>
             <csr-info>base64encodedvalue==</csr-info>
           </generate-certificate-signing-request>
         </asymmetric-key>
       </asymmetric-keys>
     </action>
   </rpc>

   RESPONSE

   <rpc-reply message-id="101"
      xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
      <certificate-signing-request
        xmlns="http://example.com/ns/example-crypto-types-usage">
        base64encodedvalue==
      </certificate-signing-request>
   </rpc-reply>

2.2.3.  The "certificate-expiration" Notification

   The following example illustrates the "certificate-expiration"
   notification, discussed in Section 2.1.4.6, with the NETCONF
   protocol.





















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

   <notification
     xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
     <eventTime>2018-05-25T00:01:00Z</eventTime>
     <asymmetric-keys xmlns="http://example.com/ns/example-crypto-types\
   -usage">
       <asymmetric-key>
         <name>ex-hidden-asymmetric-key</name>
         <certificates>
           <certificate>
             <name>ex-hidden-asymmetric-key</name>
             <certificate-expiration>
               <expiration-date>2018-08-05T14:18:53-05:00</expiration-d\
   ate>
             </certificate-expiration>
           </certificate>
         </certificates>
       </asymmetric-key>
     </asymmetric-keys>
   </notification>

2.3.  YANG Module

   This module has normative references to [RFC2119], [RFC2986],
   [RFC3447], [RFC4253], [RFC5280], [RFC5652], [RFC5915], [RFC5958],
   [RFC6031], [RFC6125], [RFC6991], [RFC7093], [RFC8174], [RFC8341], and
   [ITU.X690.2015].

   <CODE BEGINS> file "ietf-crypto-types@2021-02-10.yang"

   module ietf-crypto-types {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-crypto-types";
     prefix ct;

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

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




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     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>";

     description
       "This module defines common YANG types for cryptographic
        applications.

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

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

        This version of this YANG module is part of RFC AAAA
        (https://www.rfc-editor.org/info/rfcAAAA); 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 2021-02-10 {
       description
         "Initial version";
       reference
         "RFC AAAA: YANG Data Types and Groupings for Cryptography";
     }


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

     feature one-symmetric-key-format {
       description
         "Indicates that the server supports the



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          'one-symmetric-key-format' identity.";
     }

     feature one-asymmetric-key-format {
       description
         "Indicates that the server supports the
          'one-asymmetric-key-format' identity.";
     }

     feature symmetrically-encrypted-value-format {
       description
         "Indicates that the server supports the
          'symmetrically-encrypted-value-format' identity.";
     }

     feature asymmetrically-encrypted-value-format {
       description
         "Indicates that the server supports the
          'asymmetrically-encrypted-value-format' identity.";
     }

     feature cms-enveloped-data-format {
       description
         "Indicates that the server supports the
          'cms-enveloped-data-format' identity.";
     }

     feature cms-encrypted-data-format {
       description
         "Indicates that the server supports the
          'cms-encrypted-data-format' identity.";
     }

     feature certificate-signing-request-generation {
       description
         "Indicates that the server implements the
          'generate-certificate-signing-request' action.";
     }

     feature certificate-expiration-notification {
       description
         "Indicates that the server implements the
          'certificate-expiration' notification.";
     }

     feature password-encryption {
       description
         "Indicates that the server supports password



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          encryption.";
     }

     feature symmetric-key-encryption {
       description
         "Indicates that the server supports encryption
          of symmetric keys.";
     }

     feature private-key-encryption {
       description
         "Indicates that the server supports encryption
          of private keys.";
     }

     /*************************************************/
     /*   Base Identities for Key Format Structures   */
     /*************************************************/

     identity symmetric-key-format {
       description "Base key-format identity for symmetric keys.";
     }

     identity public-key-format {
       description "Base key-format identity for public keys.";
     }

     identity private-key-format {
       description "Base key-format identity for private keys.";
     }


     /****************************************************/
     /*   Identities for Private Key Format Structures   */
     /****************************************************/

     identity rsa-private-key-format {
       base "private-key-format";
       description
         "Indicates that the private key value is encoded
          as an RSAPrivateKey (from RFC 3447).";
       reference
         "RFC 3447: PKCS #1: RSA Cryptography
                    Specifications Version 2.2";
     }

     identity ec-private-key-format {
       base "private-key-format";



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       description
         "Indicates that the private key value is encoded
          as an ECPrivateKey (from RFC 5915)";
       reference
         "RFC 5915: Elliptic Curve Private Key Structure";
     }

     identity one-asymmetric-key-format {
       if-feature "one-asymmetric-key-format";
       base "private-key-format";
       description
         "Indicates that the private key value is a CMS
          OneAsymmetricKey structure, as defined in RFC 5958,
          encoded using ASN.1 distinguished encoding rules
          (DER), as specified in ITU-T X.690.";
       reference
         "RFC 5958: Asymmetric Key Packages
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }

     /***************************************************/
     /*   Identities for Public Key Format Structures   */
     /***************************************************/

     identity ssh-public-key-format {
       base "public-key-format";
       description
         "Indicates that the public key value is an SSH public key,
          as specified by RFC 4253, Section 6.6, i.e.:

            string    certificate or public key format
                      identifier
            byte[n]   key/certificate data.";
       reference
         "RFC 4253: The Secure Shell (SSH) Transport Layer Protocol";
     }

     identity subject-public-key-info-format {
       base "public-key-format";
       description
         "Indicates that the public key value is a SubjectPublicKeyInfo
          structure, as described in RFC 5280 encoded using ASN.1
          distinguished encoding rules (DER), as specified in
          ITU-T X.690.";



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       reference
         "RFC 5280:
            Internet X.509 Public Key Infrastructure Certificate
            and Certificate Revocation List (CRL) Profile
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }


     /******************************************************/
     /*   Identities for Symmetric Key Format Structures   */
     /******************************************************/

     identity octet-string-key-format {
       base "symmetric-key-format";
       description
         "Indicates that the key is encoded as a raw octet string.
          The length of the octet string MUST be appropriate for
          the associated algorithm's block size.

          How the associated algorithm is known is outside the
          scope of this module.  This statement also applies when
          the octet string has been encrypted.";
     }

     identity one-symmetric-key-format {
       if-feature "one-symmetric-key-format";
       base "symmetric-key-format";
       description
         "Indicates that the private key value is a CMS
          OneSymmetricKey structure, as defined in RFC 6031,
          encoded using ASN.1 distinguished encoding rules
          (DER), as specified in ITU-T X.690.";
       reference
         "RFC 6031: Cryptographic Message Syntax (CMS)
                    Symmetric Key Package Content Type
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }

     /*************************************************/
     /*   Identities for Encrytped Value Structures   */



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     /*************************************************/

     identity encrypted-value-format {
       description
         "Base format identity for encrypted values.";
     }

     identity symmetrically-encrypted-value-format {
       if-feature "symmetrically-encrypted-value-format";
       base "encrypted-value-format";
       description
         "Base format identity for symmetrically encrypted
          values.";
     }

     identity asymmetrically-encrypted-value-format {
       if-feature "asymmetrically-encrypted-value-format";
       base "encrypted-value-format";
       description
         "Base format identity for asymmetrically encrypted
          values.";
     }

     identity cms-encrypted-data-format {
       if-feature "cms-encrypted-data-format";
       base "symmetrically-encrypted-value-format";
       description
         "Indicates that the encrypted value conforms to
          the 'encrypted-data-cms' type with the constraint
          that the 'unprotectedAttrs' value is not set.";
       reference
         "RFC 5652: Cryptographic Message Syntax (CMS)
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
      }

     identity cms-enveloped-data-format {
       if-feature "cms-enveloped-data-format";
       base "asymmetrically-encrypted-value-format";
       description
         "Indicates that the encrypted value conforms to the
          'enveloped-data-cms' type with the following constraints:

          The EnvelopedData structure MUST have exactly one
          'RecipientInfo'.



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          If the asymmetric key supports public key cryptography
          (e.g., RSA), then the 'RecipientInfo' must be a
          'KeyTransRecipientInfo' with the 'RecipientIdentifier'
          using a 'subjectKeyIdentifier' with the value set using
          'method 1' in RFC 7093 over the recipient's public key.

          Otherwise, if the asymmetric key supports key agreement
          (e.g., ECC), then the 'RecipientInfo' must be a
          'KeyAgreeRecipientInfo'.  The 'OriginatorIdentifierOrKey'
          value must use the 'OriginatorPublicKey' alternative.
          The 'UserKeyingMaterial' value must not be present.
          There must be exactly one 'RecipientEncryptedKeys' value
          having the 'KeyAgreeRecipientIdentifier' set to 'rKeyId'
          with the value set using 'method 1' in RFC 7093 over the
          recipient's public key.";
       reference
         "RFC 5652: Cryptographic Message Syntax (CMS)
          RFC 7093:
            Additional Methods for Generating Key
            Identifiers Values
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
      }

     /***************************************************/
     /*   Typedefs for ASN.1 structures from RFC 2986   */
     /***************************************************/

     typedef csr-info {
       type binary;
       description
         "A CertificationRequestInfo structure, as defined in
          RFC 2986, encoded using ASN.1 distinguished encoding
          rules (DER), as specified in ITU-T X.690.";
       reference
         "RFC 2986: PKCS #10: Certification Request Syntax
                    Specification Version 1.7
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }

     typedef csr {



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       type binary;
       description
         "A CertificationRequest structure, as specified in
          RFC 2986, encoded using ASN.1 distinguished encoding
          rules (DER), as specified in ITU-T X.690.";
       reference
         "RFC 2986:
            PKCS #10: Certification Request Syntax Specification
            Version 1.7
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }

     /***************************************************/
     /*   Typedefs for ASN.1 structures from RFC 5280   */
     /***************************************************/

     typedef x509 {
       type binary;
       description
         "A Certificate structure, as specified in RFC 5280,
          encoded using ASN.1 distinguished encoding rules (DER),
          as specified in ITU-T X.690.";
       reference
         "RFC 5280:
            Internet X.509 Public Key Infrastructure Certificate
            and Certificate Revocation List (CRL) Profile
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }

     typedef crl {
       type binary;
       description
         "A CertificateList structure, as specified in RFC 5280,
          encoded using ASN.1 distinguished encoding rules (DER),
          as specified in ITU-T X.690.";
       reference
         "RFC 5280:
            Internet X.509 Public Key Infrastructure Certificate
            and Certificate Revocation List (CRL) Profile
          ITU-T X.690:



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            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }


     /***************************************************/
     /*   Typedefs for ASN.1 structures from RFC 6960   */
     /***************************************************/

     typedef oscp-request {
       type binary;
       description
         "A OCSPRequest structure, as specified in RFC 6960,
          encoded using ASN.1 distinguished encoding rules
          (DER), as specified in ITU-T X.690.";
       reference
         "RFC 6960:
            X.509 Internet Public Key Infrastructure Online
            Certificate Status Protocol - OCSP
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }

     typedef oscp-response {
       type binary;
       description
         "A OCSPResponse structure, as specified in RFC 6960,
          encoded using ASN.1 distinguished encoding rules
          (DER), as specified in ITU-T X.690.";
       reference
         "RFC 6960:
            X.509 Internet Public Key Infrastructure Online
            Certificate Status Protocol - OCSP
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }


     /***********************************************/
     /*   Typedefs for ASN.1 structures from 5652   */



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     /***********************************************/

     typedef cms {
       type binary;
       description
         "A ContentInfo structure, as specified in RFC 5652,
          encoded using ASN.1 distinguished encoding rules (DER),
          as specified in ITU-T X.690.";
       reference
         "RFC 5652:
            Cryptographic Message Syntax (CMS)
          ITU-T X.690:
            Information technology - ASN.1 encoding rules:
            Specification of Basic Encoding Rules (BER),
            Canonical Encoding Rules (CER) and Distinguished
            Encoding Rules (DER).";
     }

     typedef data-content-cms {
       type cms;
       description
         "A CMS structure whose top-most content type MUST be the
          data content type, as described by Section 4 in RFC 5652.";
       reference
         "RFC 5652: Cryptographic Message Syntax (CMS)";
     }

     typedef signed-data-cms {
       type cms;
       description
         "A CMS structure whose top-most content type MUST be the
          signed-data content type, as described by Section 5 in
          RFC 5652.";
       reference
         "RFC 5652: Cryptographic Message Syntax (CMS)";
     }

     typedef enveloped-data-cms {
       type cms;
       description
         "A CMS structure whose top-most content type MUST be the
          enveloped-data content type, as described by Section 6
          in RFC 5652.";
       reference
         "RFC 5652: Cryptographic Message Syntax (CMS)";
     }

     typedef digested-data-cms {



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       type cms;
       description
         "A CMS structure whose top-most content type MUST be the
          digested-data content type, as described by Section 7
          in RFC 5652.";
       reference
         "RFC 5652: Cryptographic Message Syntax (CMS)";
     }

     typedef encrypted-data-cms {
       type cms;
       description
         "A CMS structure whose top-most content type MUST be the
          encrypted-data content type, as described by Section 8
          in RFC 5652.";
       reference
         "RFC 5652: Cryptographic Message Syntax (CMS)";
     }

     typedef authenticated-data-cms {
       type cms;
       description
         "A CMS structure whose top-most content type MUST be the
          authenticated-data content type, as described by Section 9
          in RFC 5652.";
       reference
         "RFC 5652: Cryptographic Message Syntax (CMS)";
     }


     /*********************************************************/
     /*   Typedefs for ASN.1 structures related to RFC 5280   */
     /*********************************************************/

     typedef trust-anchor-cert-x509 {
       type x509;
       description
         "A Certificate structure that MUST encode a self-signed
          root certificate.";
     }

     typedef end-entity-cert-x509 {
       type x509;
       description
         "A Certificate structure that MUST encode a certificate
          that is neither self-signed nor having Basic constraint
          CA true.";
     }



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     /*********************************************************/
     /*   Typedefs for ASN.1 structures related to RFC 5652   */
     /*********************************************************/

     typedef trust-anchor-cert-cms {
       type signed-data-cms;
       description
         "A CMS SignedData structure that MUST contain the chain of
          X.509 certificates needed to authenticate the certificate
          presented by a client or end-entity.

          The CMS MUST contain only a single chain of certificates.
          The client or end-entity certificate MUST only authenticate
          to last intermediate CA certificate listed in the chain.

          In all cases, the chain MUST include a self-signed root
          certificate.  In the case where the root certificate is
          itself the issuer of the client or end-entity certificate,
          only one certificate is present.

          This CMS structure MAY (as applicable where this type is
          used) also contain suitably fresh (as defined by local
          policy) revocation objects with which the device can
          verify the revocation status of the certificates.

          This CMS encodes the degenerate form of the SignedData
          structure that is commonly used to disseminate X.509
          certificates and revocation objects (RFC 5280).";
       reference
         "RFC 5280:
            Internet X.509 Public Key Infrastructure Certificate
            and Certificate Revocation List (CRL) Profile.";
     }

     typedef end-entity-cert-cms {
       type signed-data-cms;
       description
         "A CMS SignedData structure that MUST contain the end
          entity certificate itself, and MAY contain any number
          of intermediate certificates leading up to a trust
          anchor certificate.  The trust anchor certificate
          MAY be included as well.

          The CMS MUST contain a single end entity certificate.
          The CMS MUST NOT contain any spurious certificates.

          This CMS structure MAY (as applicable where this type is
          used) also contain suitably fresh (as defined by local



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          policy) revocation objects with which the device can
          verify the revocation status of the certificates.

          This CMS encodes the degenerate form of the SignedData
          structure that is commonly used to disseminate X.509
          certificates and revocation objects (RFC 5280).";
       reference
         "RFC 5280:
            Internet X.509 Public Key Infrastructure Certificate
            and Certificate Revocation List (CRL) Profile.";
     }


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

     grouping encrypted-value-grouping {
       description
         "A reusable grouping for a value that has been encrypted by
          a symmetric or asymmetric key in the Keystore.";
       container encrypted-by {
         nacm:default-deny-write;
         description
           "An empty container enabling a reference to the key that
            encrypted the value to be augmented in.  The referenced
            key MUST be a symmetric key or an asymmetric key.

            A symmetric key MUST be referenced via a leaf node called
            'symmetric-key-ref'.  An asymmetric key MUST be referenced
            via a leaf node called 'asymmetric-key-ref'.

            The leaf nodes MUST be direct descendents in the data tree,
            and MAY be direct descendents in the schema tree.";
       }
       leaf encrypted-value-format {
         type identityref {
           base encrypted-value-format;
         }
         mandatory true;
         description
           "Identifies the format of the 'encrypted-value' leaf.

            If 'encrypted-by' points to a symmetric key, then a
            'symmetrically-encrypted-value-format' based identity
            MUST by set (e.g., cms-encrypted-data-format).

            If 'encrypted-by' points to an asymmetric key, then an



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            'asymmetrically-encrypted-value-format' based identity
            MUST by set (e.g., cms-enveloped-data-format).";
       }
       leaf encrypted-value {
         nacm:default-deny-write;
         type binary;
         must "../encrypted-by";
         mandatory true;
         description
           "The value, encrypted using the referenced symmetric
            or asymmetric key.  The value MUST be encoded using
            the format associated with the 'encrypted-value-format'
            leaf.";
       }
     }

     grouping password-grouping {
       description
         "A password that MAY be encrypted.";
       choice password-type {
         nacm:default-deny-write;
         mandatory true;
         description
           "Choice between password types.";
         case cleartext-password {
           leaf cleartext-password {
             nacm:default-deny-all;
             type string;
             description
               "The cleartext value of the password.";
           }
         }
         case encrypted-password {
           if-feature password-encryption;
           container encrypted-password {
             description
               "A container for the encrypted password value.";
             uses encrypted-value-grouping;
           }
         }
       }
     }

     grouping symmetric-key-grouping {
       description
         "A symmetric key.";
       leaf key-format {
         nacm:default-deny-write;



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         type identityref {
           base symmetric-key-format;
         }
         description
           "Identifies the symmetric key's format.  Implementations
            SHOULD ensure that the incoming symmetric key value is
            encoded in the specified format.

            For encrypted keys, the value is the same as it would
            have been if the key were not encrypted.";
       }
       choice key-type {
         nacm:default-deny-write;
         mandatory true;
         description
           "Choice between key types.";
         case cleartext-key {
           leaf cleartext-key {
             nacm:default-deny-all;
             type binary;
             must "../key-format";
             description
               "The binary value of the key.  The interpretation of
                the value is defined by the 'key-format' field.";
           }
         }
         case hidden-key {
           leaf hidden-key {
             type empty;
             must "not(../key-format)";
             description
               "A hidden key.  How such keys are created is outside
                the scope of this module.";
           }
         }
         case encrypted-key {
           if-feature symmetric-key-encryption;
           container encrypted-key {
             must "../key-format";
             description
               "A container for the encrypted symmetric key value.
                The interpretation of the 'encrypted-value' node
                is via the 'key-format' node";
             uses encrypted-value-grouping;
           }
         }
       }
     }



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     grouping public-key-grouping {
       description
         "A public key.";
       leaf public-key-format {
         nacm:default-deny-write;
         type identityref {
           base public-key-format;
         }
         mandatory true;
         description
           "Identifies the public key's format. Implementations SHOULD
            ensure that the incoming public key value is encoded in the
            specified format.";
       }
       leaf public-key {
         nacm:default-deny-write;
         type binary;
         mandatory true;
         description
           "The binary value of the public key.  The interpretation
            of the value is defined by 'public-key-format' field.";
       }
     }

     grouping asymmetric-key-pair-grouping {
       description
         "A private key and its associated public key.  Implementations
          SHOULD ensure that the two keys are a matching pair.";
       uses public-key-grouping;
       leaf private-key-format {
         nacm:default-deny-write;
         type identityref {
           base private-key-format;
         }
         description
           "Identifies the private key's format.  Implementations SHOULD
            ensure that the incoming private key value is encoded in the
            specified format.

            For encrypted keys, the value is the same as it would have
            been if the key were not encrypted.";
       }
       choice private-key-type {
         nacm:default-deny-write;
         mandatory true;
         description
           "Choice between key types.";
         case cleartext-private-key {



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           leaf cleartext-private-key {
             nacm:default-deny-all;
             type binary;
             must "../private-key-format";
             description
               "The value of the binary key  The key's value is
                interpreted by the 'private-key-format' field.";
           }
         }
         case hidden-private-key {
           leaf hidden-private-key {
             type empty;
             must "not(../private-key-format)";
             description
               "A hidden key.  How such keys are created is
                outside the scope of this module.";
           }
         }
         case encrypted-private-key {
           if-feature private-key-encryption;
           container encrypted-private-key {
             must "../private-key-format";
             description
              "A container for the encrypted asymmetric private key
               value.  The interpretation of the 'encrypted-value'
               node is via the 'private-key-format' node";
             uses encrypted-value-grouping;
           }
         }
       }
     }

     grouping certificate-expiration-grouping {
       description
         "A notification for when a certificate is about to, or
         already has, expired.";
       notification certificate-expiration {
         if-feature certificate-expiration-notification;
         description
           "A notification indicating that the configured certificate
            is either about to expire or has already expired.  When to
            send notifications is an implementation specific decision,
            but it is RECOMMENDED that a notification be sent once a
            month for 3 months, then once a week for four weeks, and
            then once a day thereafter until the issue is resolved.";
         leaf expiration-date {
           type yang:date-and-time;
           mandatory true;



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           description
             "Identifies the expiration date on the certificate.";
         }
       }
     }

     grouping trust-anchor-cert-grouping {
       description
         "A trust anchor certificate, and a notification for when
          it is about to (or already has) expire.";
       leaf cert-data {
         nacm:default-deny-write;
         type trust-anchor-cert-cms;
         description
           "The binary certificate data for this certificate.";
       }
       uses certificate-expiration-grouping;
     }

     grouping end-entity-cert-grouping {
       description
         "An end entity certificate, and a notification for when
          it is about to (or already has) expire.  Implementations
          SHOULD assert that, where used, the end entity certificate
          contains the expected public key.";
       leaf cert-data {
         nacm:default-deny-write;
         type end-entity-cert-cms;
         description
           "The binary certificate data for this certificate.";
       }
       uses certificate-expiration-grouping;
     }

     grouping generate-csr-grouping {
       description
         "Defines the 'generate-certificate-signing-request' action.";
       action generate-certificate-signing-request {
         if-feature certificate-signing-request-generation;
         nacm:default-deny-all;
         description
           "Generates a certificate signing request structure for
            the associated asymmetric key using the passed subject
            and attribute values.

            This action statement is only available when the
            associated 'public-key-format' node's value is
            'subject-public-key-info-format'.";



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         reference
           "RFC 6125:
             Representation and Verification of Domain-Based
             Application Service Identity within Internet Public Key
             Infrastructure Using X.509 (PKIX) Certificates in the
             Context of Transport Layer Security (TLS)";
         input {
           leaf csr-info {
             type ct:csr-info;
             mandatory true;
             description
               "A CertificationRequestInfo structure, as defined in
                RFC 2986.

                Enables the client to provide a fully-populated
                CertificationRequestInfo structure that the server
                only needs to sign in order to generate the complete
                'CertificationRequest' structure to return in the
                'output'.

                The 'AlgorithmIdentifier' field contained inside
                the 'SubjectPublicKeyInfo' field MUST be one known
                to be supported by the device.";
             reference
               "RFC 2986:
                  PKCS #10: Certification Request Syntax Specification
                RFC AAAA:
                  YANG Data Types and Groupings for Cryptography";
           }
         }
         output {
           leaf certificate-signing-request {
             type ct:csr;
             mandatory true;
             description
               "A CertificationRequest structure, as defined in
                RFC 2986.";
             reference
               "RFC 2986:
                  PKCS #10: Certification Request Syntax Specification
                RFC AAAA:
                  YANG Data Types and Groupings for Cryptography";
           }
         }
       }
     } // generate-csr-grouping

     grouping asymmetric-key-pair-with-cert-grouping {



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       description
         "A private/public key pair and an associated certificate.
          Implementations SHOULD assert that certificates contain
          the matching public key.";
       uses asymmetric-key-pair-grouping;
       uses end-entity-cert-grouping;
       uses generate-csr-grouping;
     } // asymmetric-key-pair-with-cert-grouping

     grouping asymmetric-key-pair-with-certs-grouping {
       description
         "A private/public key pair and associated certificates.
          Implementations SHOULD assert that certificates contain
          the matching public key.";
       uses asymmetric-key-pair-grouping;
       container certificates {
         nacm:default-deny-write;
         description
           "Certificates associated with this asymmetric key.";
         list certificate {
           key "name";
           description
             "A certificate for this asymmetric key.";
           leaf name {
             type string;
             description
               "An arbitrary name for the certificate.";
           }
           uses end-entity-cert-grouping {
             refine cert-data {
               mandatory true;
             }
           }
         }
       }
       uses generate-csr-grouping;
     } // asymmetric-key-pair-with-certs-grouping

   }

   <CODE ENDS>

3.  Security Considerations








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3.1.  No Support for CRMF

   This document uses PKCS #10 [RFC2986] for the "generate-certificate-
   signing-request" action.  The use of Certificate Request Message
   Format (CRMF) [RFC4211] was considered, but it was unclear if there
   was market demand for it.  If it is desired to support CRMF in the
   future, a backwards compatible solution can be defined at that time.

3.2.  No Support for Key Generation

   Early revisions of this document included "rpc" statements for
   generating symmetric and asymmetric keys.  There statements were
   removed due to an inability to obtain consensus for how to identify
   the key-algorithm to use.  Thusly, the solution presented in this
   document only supports keys to be configured via an external client,
   which does not support Security best practice.

3.3.  Unconstrained Public Key Usage

   This module defines the "public-key-grouping" grouping, which enables
   the configuration of public keys without constraints on their usage,
   e.g., what operations the key is allowed to be used for (encryption,
   verification, both).

   The "asymmetric-key-pair-grouping" grouping uses the aforementioned
   "public-key-grouping" grouping, and carries the same traits.

   The "asymmetric-key-pair-with-cert-grouping" grouping uses the
   aforementioned "asymmetric-key-pair-grouping" grouping, whereby each
   certificate may constrain the usage of the public key according to
   local policy.

3.4.  Unconstrained Private Key Usage

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

   The "asymmetric-key-pair-with-cert-grouping" uses the aforementioned
   "asymmetric-key-pair-grouping" grouping, whereby configured
   certificates (e.g., identity certificates) may constrain the use of
   the public key according to local policy.








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3.5.  Strength of Keys Configured

   When configuring key values, implementations SHOULD ensure that the
   strength of the key being configured is not greater than the strength
   of the underlying secure transport connection over which it is
   communicated.  Implementations SHOULD fail the write-request if ever
   the strength of the private key is greater then the strength of the
   underlying transport.

3.6.  Encrypting Passwords

   The module contained within this document enables passwords to be
   encrypted.  Passwords may be encrypted via a symmetric key using the
   "cms-encrypted-data-format" format.  This format uses the CMS
   EncryptedData structure, which allows any encryption algorithm to be
   used.

   In order to thrawt rainbow attacks, algorithms that result in a
   unique output for the same input SHOULD be used.  For instance, AES
   using "EBC" SHOULD NOT be used to encrypt passwords, whereas "CBC"
   mode is okay since it a unique initialization vector (IV) should be
   used for each run.

3.7.  Deletion of Cleartext Key Values

   This module defines storage for cleartext key values that SHOULD be
   zeroized when deleted, so as to prevent the remnants of their
   persisted storage locations from being analyzed in any meaningful
   way.

   The cleartext key values are the "cleartext-key" node defined in the
   "symmetric-key-grouping" grouping (Section 2.1.4.3) and the
   "cleartext-private-key" node defined in the "asymmetric-key-pair-
   grouping" grouping ("Section 2.1.4.5).

3.8.  The "ietf-crypto-types" YANG Module

   The YANG module in this document 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 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.





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

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

   *  The "cleartext-key" node:

         The "cleartext-key" node defined in the "symmetric-key-
         grouping" grouping is additionally sensitive to read operations
         such that, in normal use cases, it should never be returned to
         a client.  For this reason, the NACM extension "default-deny-
         all" has been applied to it.

   *  The "cleartext-private-key" node:

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

   All of the writable data nodes defined by all the groupings defined
   in this module may be considered sensitive or vulnerable in some
   network environments.  For instance, even the modification of a
   public key or a certificate can dramatically alter the implemented
   security policy.  For this reason, the NACM extension "default-deny-
   write" has been applied to all the data nodes defined in the module.

   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:

   *  generate-certificate-signing-request:

         This "action" statement SHOULD only be executed by authorized
         users.  For this reason, the NACM extension "default-deny-all"
         has been applied.  Note that NACM uses "default-deny-all" to
         protect "RPC" and "action" statements; it does not define,
         e.g., an extension called "default-deny-execute".






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         For this action, it is RECOMMENDED that implementations assert
         channel binding [RFC5056], so as to ensure that the application
         layer that sent the request is the same as the device
         authenticated when the secure transport layer was established.

4.  IANA Considerations

4.1.  The "IETF XML" Registry

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

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

4.2.  The "YANG Module Names" Registry

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

      name:         ietf-crypto-types
      namespace:    urn:ietf:params:xml:ns:yang:ietf-crypto-types
      prefix:       ct
      reference:    RFC AAAA

5.  References

5.1.  Normative References

   [ITU.X680.2015]
              International Telecommunication Union, "Information
              technology - Abstract Syntax Notation One (ASN.1):
              Specification of basic notation", ITU-T Recommendation
              X.680, ISO/IEC 8824-1:2015, August 2015,
              <https://www.itu.int/rec/T-REC-X.680/>.

   [ITU.X690.2015]
              International Telecommunication Union, "Information
              Technology - ASN.1 encoding rules: Specification of Basic
              Encoding Rules (BER), Canonical Encoding Rules (CER) and
              Distinguished Encoding Rules (DER)", ITU-T Recommendation
              X.690, ISO/IEC 8825-1:2015, August 2015,
              <https://www.itu.int/rec/T-REC-X.690/>.





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   [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>.

   [RFC3447]  Jonsson, J. and B. Kaliski, "Public-Key Cryptography
              Standards (PKCS) #1: RSA Cryptography Specifications
              Version 2.1", RFC 3447, DOI 10.17487/RFC3447, February
              2003, <https://www.rfc-editor.org/info/rfc3447>.

   [RFC4253]  Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253,
              January 2006, <https://www.rfc-editor.org/info/rfc4253>.

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
              <https://www.rfc-editor.org/info/rfc5280>.

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

   [RFC5958]  Turner, S., "Asymmetric Key Packages", RFC 5958,
              DOI 10.17487/RFC5958, August 2010,
              <https://www.rfc-editor.org/info/rfc5958>.

   [RFC6031]  Turner, S. and R. Housley, "Cryptographic Message Syntax
              (CMS) Symmetric Key Package Content Type", RFC 6031,
              DOI 10.17487/RFC6031, December 2010,
              <https://www.rfc-editor.org/info/rfc6031>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7093]  Turner, S., Kent, S., and J. Manger, "Additional Methods
              for Generating Key Identifiers Values", RFC 7093,
              DOI 10.17487/RFC7093, December 2013,
              <https://www.rfc-editor.org/info/rfc7093>.

   [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>.






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   [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>.

5.2.  Informative 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-18, 20 August 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-crypto-
              types-18>.

   [I-D.ietf-netconf-http-client-server]
              Watsen, K., "YANG Groupings for HTTP Clients and HTTP
              Servers", Work in Progress, Internet-Draft, draft-ietf-
              netconf-http-client-server-05, 20 August 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-http-
              client-server-05>.

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

   [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-21, 20 August 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-netconf-
              client-server-21>.

   [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-21, 20 August 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-restconf-
              client-server-21>.

   [I-D.ietf-netconf-ssh-client-server]
              Watsen, K., "YANG Groupings for SSH Clients and SSH
              Servers", Work in Progress, Internet-Draft, draft-ietf-



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              netconf-ssh-client-server-22, 20 August 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-ssh-
              client-server-22>.

   [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-08, 20 August 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-tcp-
              client-server-08>.

   [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-22, 20 August 2020,
              <https://tools.ietf.org/html/draft-ietf-netconf-tls-
              client-server-22>.

   [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-13, 20 August 2020, <https://tools.ietf.org/html/
              draft-ietf-netconf-trust-anchors-13>.

   [RFC2986]  Nystrom, M. and B. Kaliski, "PKCS #10: Certification
              Request Syntax Specification Version 1.7", RFC 2986,
              DOI 10.17487/RFC2986, November 2000,
              <https://www.rfc-editor.org/info/rfc2986>.

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

   [RFC4211]  Schaad, J., "Internet X.509 Public Key Infrastructure
              Certificate Request Message Format (CRMF)", RFC 4211,
              DOI 10.17487/RFC4211, September 2005,
              <https://www.rfc-editor.org/info/rfc4211>.

   [RFC5056]  Williams, N., "On the Use of Channel Bindings to Secure
              Channels", RFC 5056, DOI 10.17487/RFC5056, November 2007,
              <https://www.rfc-editor.org/info/rfc5056>.

   [RFC5915]  Turner, S. and D. Brown, "Elliptic Curve Private Key
              Structure", RFC 5915, DOI 10.17487/RFC5915, June 2010,
              <https://www.rfc-editor.org/info/rfc5915>.






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

   [RFC6125]  Saint-Andre, P. and J. Hodges, "Representation and
              Verification of Domain-Based Application Service Identity
              within Internet Public Key Infrastructure Using X.509
              (PKIX) Certificates in the Context of Transport Layer
              Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
              2011, <https://www.rfc-editor.org/info/rfc6125>.

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

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

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

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

Appendix A.  Change Log

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

A.1.  I-D to 00

   *  Removed groupings and notifications.

   *  Added typedefs for identityrefs.

   *  Added typedefs for other RFC 5280 structures.

   *  Added typedefs for other RFC 5652 structures.

   *  Added convenience typedefs for RFC 4253, RFC 5280, and RFC 5652.

A.2.  00 to 01




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   *  Moved groupings from the draft-ietf-netconf-keystore here.

A.3.  01 to 02

   *  Removed unwanted "mandatory" and "must" statements.

   *  Added many new crypto algorithms (thanks Haiguang!)

   *  Clarified in asymmetric-key-pair-with-certs-grouping, in
      certificates/certificate/name/description, that if the name MUST
      NOT match the name of a certificate that exists independently in
      <operational>, enabling certs installed by the manufacturer (e.g.,
      an IDevID).

A.4.  02 to 03

   *  renamed base identity 'asymmetric-key-encryption-algorithm' to
      'asymmetric-key-algorithm'.

   *  added new 'asymmetric-key-algorithm' identities for secp192r1,
      secp224r1, secp256r1, secp384r1, and secp521r1.

   *  removed 'mac-algorithm' identities for mac-aes-128-ccm, mac-aes-
      192-ccm, mac-aes-256-ccm, mac-aes-128-gcm, mac-aes-192-gcm, mac-
      aes-256-gcm, and mac-chacha20-poly1305.

   *  for all -cbc and -ctr identities, renamed base identity
      'symmetric-key-encryption-algorithm' to 'encryption-algorithm'.

   *  for all -ccm and -gcm identities, renamed base identity
      'symmetric-key-encryption-algorithm' to 'encryption-and-mac-
      algorithm' and renamed the identity to remove the "enc-" prefix.

   *  for all the 'signature-algorithm' based identities, renamed from
      'rsa-*' to 'rsassa-*'.

   *  removed all of the "x509v3-" prefixed 'signature-algorithm' based
      identities.

   *  added 'key-exchange-algorithm' based identities for 'rsaes-oaep'
      and 'rsaes-pkcs1-v1_5'.

   *  renamed typedef 'symmetric-key-encryption-algorithm-ref' to
      'symmetric-key-algorithm-ref'.

   *  renamed typedef 'asymmetric-key-encryption-algorithm-ref' to
      'asymmetric-key-algorithm-ref'.




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   *  added typedef 'encryption-and-mac-algorithm-ref'.

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

A.5.  03 to 04

   *  ran YANG module through formatter.

A.6.  04 to 05

   *  fixed broken symlink causing reformatted YANG module to not show.

A.7.  05 to 06

   *  Added NACM annotations.

   *  Updated Security Considerations section.

   *  Added 'asymmetric-key-pair-with-cert-grouping' grouping.

   *  Removed text from 'permanently-hidden' enum regarding such keys
      not being backed up or restored.

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

   *  Added an explanation to the 'public-key-grouping' and 'asymmetric-
      key-pair-grouping' statements as for why the nodes are not
      mandatory (e.g., because they may exist only in <operational>.

   *  Added 'must' expressions to the 'public-key-grouping' and
      'asymmetric-key-pair-grouping' statements ensuring sibling nodes
      are either all exist or do not all exist.

   *  Added an explanation to the 'permanently-hidden' that the value
      cannot be configured directly by clients and servers MUST fail any
      attempt to do so.

   *  Added 'trust-anchor-certs-grouping' and 'end-entity-certs-
      grouping' (the plural form of existing groupings).

   *  Now states that keys created in <operational> by the *-hidden-key
      actions are bound to the lifetime of the parent 'config true'
      node, and that subsequent invocations of either action results in
      a failure.





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A.8.  06 to 07

   *  Added clarifications that implementations SHOULD assert that
      configured certificates contain the matching public key.

   *  Replaced the 'generate-hidden-key' and 'install-hidden-key'
      actions with special 'crypt-hash' -like input/output values.

A.9.  07 to 08

   *  Removed the 'generate-key and 'hidden-key' features.

   *  Added grouping symmetric-key-grouping

   *  Modified 'asymmetric-key-pair-grouping' to have a 'choice'
      statement for the keystone module to augment into, as well as
      replacing the 'union' with leafs (having different NACM settings.

A.10.  08 to 09

   *  Converting algorithm from identities to enumerations.

A.11.  09 to 10

   *  All of the below changes are to the algorithm enumerations defined
      in ietf-crypto-types.

   *  Add in support for key exchange over x.25519 and x.448 based on
      RFC 8418.

   *  Add in SHAKE-128, SHAKE-224, SHAKE-256, SHAKE-384 and SHAKE 512

   *  Revise/add in enum of signature algorithm for x25519 and x448

   *  Add in des3-cbc-sha1 for IPSec

   *  Add in sha1-des3-kd for IPSec

   *  Add in definit for rc4-hmac and rc4-hmac-exp.  These two
      algorithms have been deprecated in RFC 8429.  But some existing
      draft in i2nsf may still want to use them.

   *  Add x25519 and x448 curve for asymmetric algorithms

   *  Add signature algorithms ed25519, ed25519-cts, ed25519ph

   *  add signature algorithms ed448, ed448ph




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   *  Add in rsa-sha2-256 and rsa-sha2-512 for SSH protocols (rfc8332)

A.12.  10 to 11

   *  Added a "key-format" identity.

   *  Added symmetric keys to the example in Section 2.2.

A.13.  11 to 12

   *  Removed all non-essential (to NC/RC) algorithm types.

   *  Moved remaining algorithm types each into its own module.

   *  Added a 'config false' "algorithms-supported" list to each of the
      algorithm-type modules.

A.14.  12 to 13

   *  Added the four features: "[encrypted-]one-[a]symmetric-key-
      format", each protecting a 'key-format' identity of the same name.

   *  Added 'must' expressions asserting that the 'key-format' leaf
      exists whenever a non-hidden key is specified.

   *  Improved the 'description' statements and added 'reference'
      statements for the 'key-format' identities.

   *  Added a questionable forward reference to "encrypted-*" leafs in a
      couple 'when' expressions.

   *  Did NOT move "config false" alg-supported lists to SSH/TLS drafts.

A.15.  13 to 14

   *  Resolved the "FIXME: forward ref" issue by modulating 'must',
      'when', and 'mandatory' expressions.

   *  Moved the 'generatesymmetric-key' and 'generate-asymmetric-key'
      actions from ietf-keystore to ietf-crypto-types, now as RPCs.

   *  Cleaned up various description statements and removed lingering
      FIXMEs.

   *  Converted the "iana-<alg-type>-algs" YANG modules to IANA
      registries with instructions for how to generate modules from the
      registries, whenever they may be updated.




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A.16.  14 to 15

   *  Removed the IANA-maintained registries for symmetric, asymmetric,
      and hash algorithms.

   *  Removed the "generate-symmetric-key" and "generate-asymmetric-key"
      RPCs.

   *  Removed the "algorithm" node in the various symmetric and
      asymmetric key groupings.

   *  Added 'typedef csr' and 'feature certificate-signing-request-
      generation'.

   *  Refined a usage of "end-entity-cert-grouping" to make the "cert"
      node mandatory true.

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

A.17.  15 to 16

   *  Updated draft title (refer to "Groupings" too).

   *  Removed 'end-entity-certs-grouping' as it wasn't being used
      anywhere.

   *  Removed 'trust-anchor-certs-grouping' as it was no longer being
      used after modifying 'local-or-truststore-certs-grouping' to use
      lists (not leaf-lists).

   *  Renamed "cert" to "cert-data" in trust-anchor-cert-grouping.

   *  Added "csr-info" typedef, to complement the existing "csr"
      typedef.

   *  Added "ocsp-request" and "ocsp-response" typedefs, to complement
      the existing "crl" typedef.

   *  Added "encrypted" cases to both symmetric-key-grouping and
      asymmetric-key-pair-grouping (Moved from Keystore draft).

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

   *  Updated the Security Considerations section.

A.18.  16 to 17




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   *  [Re]-added a "Strength of Keys Configured" Security Consideration

   *  Prefixed "cleartext-" in the "key" and "private-key" node names.

A.19.  17 to 18

   *  Fixed issues found by the SecDir review of the "keystore" draft.

   *  Added "password-grouping", discussed during the IETF 108 session.

A.20.  18 to 19

   *  Added a "Unconstrained Public Key Usage" Security Consideration to
      address concern raised by SecDir of the 'truststore' draft.

   *  Added a "Unconstrained Private Key Usage" Security Consideration
      to address concern raised by SecDir of the 'truststore' draft.

   *  Changed the encryption strategy, after conferring with Russ
      Housley.

   *  Added a "password-grouping" example to the "crypto-types-usage"
      example.

   *  Added an "Encrypting Passwords" section to Security Consideration.

   *  Addressed other comments raised by YANG Doctor.

Acknowledgements

   The authors would like to thank for following for lively discussions
   on list and in the halls (ordered by first name): Balazs Kovacs, Eric
   Voit, Juergen Schoenwaelder, Liang Xia, Martin Bjorklund, Nick
   Hancock, Rich Salz, Rob Wilton, Russ Housley, Sandra Murphy, Tom
   Petch, and Wang Haiguang.

Author's Address

   Kent Watsen
   Watsen Networks

   Email: kent+ietf@watsen.net









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