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Versions: (draft-ietf-netconf-system-keychain) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20

NETCONF Working Group                                          K. Watsen
Internet-Draft                                           Watsen Networks
Intended status: Standards Track                            May 20, 2020
Expires: November 21, 2020


                    A YANG Data Model for a Keystore
                     draft-ietf-netconf-keystore-17

Abstract

   This document defines a YANG 1.1 module called "ietf-keystore" that
   enables centralized configuration of both symmetric and asymmetric
   keys.  The secret value for both key types may be encrypted.
   Asymmetric keys may be associated with certificates.  Notifications
   are sent when certificates are about to expire.

Editorial Note (To be removed by RFC Editor)

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

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

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

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

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

   o  "2020-05-20" --> the publication date of this draft

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

   o  Appendix A.  Change Log

Note to Reviewers (To be removed by RFC Editor)

   This document presents a YANG module or modules that is/are part of a
   collection of drafts that work together to produce the ultimate goal
   of the NETCONF WG: to define configuration modules for NETCONF client
   and servers, and RESTCONF client and servers.




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   The relationship between the various drafts in the collection is
   presented in the below diagram.

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


   Full draft names and link to drafts:

   o  draft-ietf-netconf-crypto-types (html [1])

   o  draft-ietf-netconf-trust-anchors (html [2])

   o  draft-ietf-netconf-keystore (html [3])

   o  draft-ietf-netconf-tcp-client-server (html [4])

   o  draft-ietf-netconf-ssh-client-server (html [5])

   o  draft-ietf-netconf-tls-client-server (html [6])

   o  draft-ietf-netconf-http-client-server (html [7])

   o  draft-ietf-netconf-netconf-client-server (html [8])

   o  draft-ietf-netconf-restconf-client-server (html [9])





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Status of This Memo

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

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

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

   This Internet-Draft will expire on November 21, 2020.

Copyright Notice

   Copyright (c) 2020 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  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   5
   3.  The Keystore Model  . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .  13
       3.2.1.  A Keystore Instance . . . . . . . . . . . . . . . . .  13
       3.2.2.  Notable Keystore Groupings  . . . . . . . . . . . . .  16
     3.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  19
   4.  Support for Built-in Keys . . . . . . . . . . . . . . . . . .  28
   5.  Encrypting Keys in Configuration  . . . . . . . . . . . . . .  31
     5.1.  Root Key  . . . . . . . . . . . . . . . . . . . . . . . .  31
     5.2.  Configuring Encrypting Keys . . . . . . . . . . . . . . .  32
     5.3.  Migrating Configuration to Another Server . . . . . . . .  32
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  33



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   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  34
     7.1.  The IETF XML Registry . . . . . . . . . . . . . . . . . .  34
     7.2.  The YANG Module Names Registry  . . . . . . . . . . . . .  35
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  35
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  35
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  35
     8.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .  36
   Appendix A.  Change Log . . . . . . . . . . . . . . . . . . . . .  38
     A.1.  00 to 01  . . . . . . . . . . . . . . . . . . . . . . . .  38
     A.2.  01 to 02  . . . . . . . . . . . . . . . . . . . . . . . .  38
     A.3.  02 to 03  . . . . . . . . . . . . . . . . . . . . . . . .  38
     A.4.  03 to 04  . . . . . . . . . . . . . . . . . . . . . . . .  38
     A.5.  04 to 05  . . . . . . . . . . . . . . . . . . . . . . . .  39
     A.6.  05 to 06  . . . . . . . . . . . . . . . . . . . . . . . .  39
     A.7.  06 to 07  . . . . . . . . . . . . . . . . . . . . . . . .  39
     A.8.  07 to 08  . . . . . . . . . . . . . . . . . . . . . . . .  39
     A.9.  08 to 09  . . . . . . . . . . . . . . . . . . . . . . . .  39
     A.10. 09 to 10  . . . . . . . . . . . . . . . . . . . . . . . .  40
     A.11. 10 to 11  . . . . . . . . . . . . . . . . . . . . . . . .  40
     A.12. 11 to 12  . . . . . . . . . . . . . . . . . . . . . . . .  40
     A.13. 12 to 13  . . . . . . . . . . . . . . . . . . . . . . . .  41
     A.14. 13 to 14  . . . . . . . . . . . . . . . . . . . . . . . .  41
     A.15. 14 to 15  . . . . . . . . . . . . . . . . . . . . . . . .  41
     A.16. 15 to 16  . . . . . . . . . . . . . . . . . . . . . . . .  41
     A.17. 16 to 17  . . . . . . . . . . . . . . . . . . . . . . . .  41
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  42
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  42

1.  Introduction

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

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

   Special consideration has been given for systems that have
   cryptographic hardware, such as a Trusted Protection Module (TPM).
   These systems are unique in that the cryptographic hardware hides the
   secret key values.  To support such hardware, symmetric keys may have
   the value "hidden-key" and asymmetric keys may have the value
   "hidden-private-key".  While how such keys are created or destroyed



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   is outside the scope of this document, the Keystore can contain
   entries for such keys, enabling them to be referenced by other
   configuration elements.

   This document in compliant with Network Management Datastore
   Architecture (NMDA) [RFC8342].  For instance, keys and associated
   certificates installed during manufacturing (e.g., for a IDevID
   [Std-802.1AR-2009] certificate), are expected to appear in
   <operational> (see Section 4).

   It is not required that a system has an operating system level
   Keystore utility to implement this module.

2.  Requirements 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.

3.  The Keystore Model

3.1.  Tree Diagram

   This section provides a tree diagrams [RFC8340] for the "ietf-
   keystore" module that presents both the protocol-accessible
   "keystore" as well the all the groupings intended for external usage.

   module: ietf-keystore
     +--rw keystore
        +--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)
        |     |  +--:(private-key)
        |     |  |  +--rw private-key?                      binary
        |     |  +--:(hidden-private-key)
        |     |  |  +--rw hidden-private-key?               empty
        |     |  +--:(encrypted-private-key)
        |     |     +--rw encrypted-private-key
        |     |        +--rw (key-type)
        |     |        |  +--:(symmetric-key-ref)
        |     |        |  |  +--rw symmetric-key-ref?    leafref
        |     |        |  |          {keystore-supported}?



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        |     |        |  +--:(asymmetric-key-ref)
        |     |        |     +--rw asymmetric-key-ref?   leafref
        |     |        |             {keystore-supported}?
        |     |        +--rw value?                      binary
        |     +--rw certificates
        |     |  +--rw certificate* [name]
        |     |     +--rw name                      string
        |     |     +--rw cert                      end-entity-cert-cms
        |     |     +---n certificate-expiration
        |     |        +-- expiration-date    yang:date-and-time
        |     +---x generate-certificate-signing-request
        |             {certificate-signing-request-generation}?
        |        +---w input
        |        |  +---w subject       binary
        |        |  +---w attributes?   binary
        |        +--ro output
        |           +--ro certificate-signing-request    ct:csr
        +--rw symmetric-keys
           +--rw symmetric-key* [name]
              +--rw name                   string
              +--rw key-format?            identityref
              +--rw (key-type)
                 +--:(key)
                 |  +--rw key?             binary
                 +--:(hidden-key)
                 |  +--rw hidden-key?      empty
                 +--:(encrypted-key)
                    +--rw encrypted-key
                       +--rw (key-type)
                       |  +--:(symmetric-key-ref)
                       |  |  +--rw symmetric-key-ref?    leafref
                       |  |          {keystore-supported}?
                       |  +--:(asymmetric-key-ref)
                       |     +--rw asymmetric-key-ref?   leafref
                       |             {keystore-supported}?
                       +--rw value?                      binary

     grouping key-reference-type-grouping
       +-- (key-type)
          +--:(symmetric-key-ref)
          |  +-- symmetric-key-ref?
          |          -> /keystore/symmetric-keys/symmetric-key/name
          |          {keystore-supported}?
          +--:(asymmetric-key-ref)
             +-- asymmetric-key-ref?
                     -> /keystore/asymmetric-keys/asymmetric-key/name
                     {keystore-supported}?
     grouping encrypted-value-grouping



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       +-- (key-type)
       |  +--:(symmetric-key-ref)
       |  |  +-- symmetric-key-ref?
       |  |          -> /keystore/symmetric-keys/symmetric-key/name
       |  |          {keystore-supported}?
       |  +--:(asymmetric-key-ref)
       |     +-- asymmetric-key-ref?
       |             -> /keystore/asymmetric-keys/asymmetric-key/name
       |             {keystore-supported}?
       +-- value?                      binary
     grouping symmetric-key-grouping
       +-- key-format?            identityref
       +-- (key-type)
          +--:(key)
          |  +-- key?             binary
          +--:(hidden-key)
          |  +-- hidden-key?      empty
          +--:(encrypted-key)
             +-- encrypted-key
                +-- (key-type)
                |  +--:(symmetric-key-ref)
                |  |  +-- symmetric-key-ref?    leafref
                |  |          {keystore-supported}?
                |  +--:(asymmetric-key-ref)
                |     +-- asymmetric-key-ref?   leafref
                |             {keystore-supported}?
                +-- value?                      binary
     grouping asymmetric-key-pair-grouping
       +-- public-key-format              identityref
       +-- public-key                     binary
       +-- private-key-format?            identityref
       +-- (private-key-type)
          +--:(private-key)
          |  +-- private-key?             binary
          +--:(hidden-private-key)
          |  +-- hidden-private-key?      empty
          +--:(encrypted-private-key)
             +-- encrypted-private-key
                +-- (key-type)
                |  +--:(symmetric-key-ref)
                |  |  +-- symmetric-key-ref?    leafref
                |  |          {keystore-supported}?
                |  +--:(asymmetric-key-ref)
                |     +-- asymmetric-key-ref?   leafref
                |             {keystore-supported}?
                +-- value?                      binary
     grouping asymmetric-key-pair-with-cert-grouping
       +-- public-key-format                       identityref



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       +-- public-key                              binary
       +-- private-key-format?                     identityref
       +-- (private-key-type)
       |  +--:(private-key)
       |  |  +-- private-key?                      binary
       |  +--:(hidden-private-key)
       |  |  +-- hidden-private-key?               empty
       |  +--:(encrypted-private-key)
       |     +-- encrypted-private-key
       |        +-- (key-type)
       |        |  +--:(symmetric-key-ref)
       |        |  |  +-- symmetric-key-ref?    leafref
       |        |  |          {keystore-supported}?
       |        |  +--:(asymmetric-key-ref)
       |        |     +-- asymmetric-key-ref?   leafref
       |        |             {keystore-supported}?
       |        +-- value?                      binary
       +-- cert?                                   end-entity-cert-cms
       +---n certificate-expiration
       |  +-- expiration-date    yang:date-and-time
       +---x generate-certificate-signing-request
               {certificate-signing-request-generation}?
          +---w input
          |  +---w subject       binary
          |  +---w attributes?   binary
          +--ro output
             +--ro certificate-signing-request    ct:csr
     grouping asymmetric-key-pair-with-certs-grouping
       +-- public-key-format                       identityref
       +-- public-key                              binary
       +-- private-key-format?                     identityref
       +-- (private-key-type)
       |  +--:(private-key)
       |  |  +-- private-key?                      binary
       |  +--:(hidden-private-key)
       |  |  +-- hidden-private-key?               empty
       |  +--:(encrypted-private-key)
       |     +-- encrypted-private-key
       |        +-- (key-type)
       |        |  +--:(symmetric-key-ref)
       |        |  |  +-- symmetric-key-ref?    leafref
       |        |  |          {keystore-supported}?
       |        |  +--:(asymmetric-key-ref)
       |        |     +-- asymmetric-key-ref?   leafref
       |        |             {keystore-supported}?
       |        +-- value?                      binary
       +-- certificates
       |  +-- certificate* [name]



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       |     +-- name?                     string
       |     +-- cert                      end-entity-cert-cms
       |     +---n certificate-expiration
       |        +-- expiration-date    yang:date-and-time
       +---x generate-certificate-signing-request
               {certificate-signing-request-generation}?
          +---w input
          |  +---w subject       binary
          |  +---w attributes?   binary
          +--ro output
             +--ro certificate-signing-request    ct:csr
     grouping asymmetric-key-certificate-ref-grouping
       +-- asymmetric-key?   ks:asymmetric-key-ref
       +-- certificate?      leafref
     grouping local-or-keystore-symmetric-key-grouping
       +-- (local-or-keystore)
          +--:(local) {local-definitions-supported}?
          |  +-- local-definition
          |     +-- key-format?            identityref
          |     +-- (key-type)
          |        +--:(key)
          |        |  +-- key?             binary
          |        +--:(hidden-key)
          |        |  +-- hidden-key?      empty
          |        +--:(encrypted-key)
          |           +-- encrypted-key
          |              +-- (key-type)
          |              |  +--:(symmetric-key-ref)
          |              |  |  +-- symmetric-key-ref?    leafref
          |              |  |          {keystore-supported}?
          |              |  +--:(asymmetric-key-ref)
          |              |     +-- asymmetric-key-ref?   leafref
          |              |             {keystore-supported}?
          |              +-- value?                      binary
          +--:(keystore) {keystore-supported}?
             +-- keystore-reference?   ks:symmetric-key-ref
     grouping local-or-keystore-asymmetric-key-grouping
       +-- (local-or-keystore)
          +--:(local) {local-definitions-supported}?
          |  +-- local-definition
          |     +-- public-key-format              identityref
          |     +-- public-key                     binary
          |     +-- private-key-format?            identityref
          |     +-- (private-key-type)
          |        +--:(private-key)
          |        |  +-- private-key?             binary
          |        +--:(hidden-private-key)
          |        |  +-- hidden-private-key?      empty



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          |        +--:(encrypted-private-key)
          |           +-- encrypted-private-key
          |              +-- (key-type)
          |              |  +--:(symmetric-key-ref)
          |              |  |  +-- symmetric-key-ref?    leafref
          |              |  |          {keystore-supported}?
          |              |  +--:(asymmetric-key-ref)
          |              |     +-- asymmetric-key-ref?   leafref
          |              |             {keystore-supported}?
          |              +-- value?                      binary
          +--:(keystore) {keystore-supported}?
             +-- keystore-reference?   ks:asymmetric-key-ref
     grouping local-or-keystore-asymmetric-key-with-certs-grouping
       +-- (local-or-keystore)
          +--:(local) {local-definitions-supported}?
          |  +-- local-definition
          |     +-- public-key-format                       identityref
          |     +-- public-key                              binary
          |     +-- private-key-format?                     identityref
          |     +-- (private-key-type)
          |     |  +--:(private-key)
          |     |  |  +-- private-key?                      binary
          |     |  +--:(hidden-private-key)
          |     |  |  +-- hidden-private-key?               empty
          |     |  +--:(encrypted-private-key)
          |     |     +-- encrypted-private-key
          |     |        +-- (key-type)
          |     |        |  +--:(symmetric-key-ref)
          |     |        |  |  +-- symmetric-key-ref?    leafref
          |     |        |  |          {keystore-supported}?
          |     |        |  +--:(asymmetric-key-ref)
          |     |        |     +-- asymmetric-key-ref?   leafref
          |     |        |             {keystore-supported}?
          |     |        +-- value?                      binary
          |     +-- certificates
          |     |  +-- certificate* [name]
          |     |     +-- name?                     string
          |     |     +-- cert                      end-entity-cert-cms
          |     |     +---n certificate-expiration
          |     |        +-- expiration-date    yang:date-and-time
          |     +---x generate-certificate-signing-request
          |             {certificate-signing-request-generation}?
          |        +---w input
          |        |  +---w subject       binary
          |        |  +---w attributes?   binary
          |        +--ro output
          |           +--ro certificate-signing-request    ct:csr
          +--:(keystore) {keystore-supported}?



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             +-- keystore-reference?   ks:asymmetric-key-ref
     grouping local-or-keystore-end-entity-cert-with-key-grouping
       +-- (local-or-keystore)
          +--:(local) {local-definitions-supported}?
          |  +-- local-definition
          |     +-- public-key-format                       identityref
          |     +-- public-key                              binary
          |     +-- private-key-format?                     identityref
          |     +-- (private-key-type)
          |     |  +--:(private-key)
          |     |  |  +-- private-key?                      binary
          |     |  +--:(hidden-private-key)
          |     |  |  +-- hidden-private-key?               empty
          |     |  +--:(encrypted-private-key)
          |     |     +-- encrypted-private-key
          |     |        +-- (key-type)
          |     |        |  +--:(symmetric-key-ref)
          |     |        |  |  +-- symmetric-key-ref?    leafref
          |     |        |  |          {keystore-supported}?
          |     |        |  +--:(asymmetric-key-ref)
          |     |        |     +-- asymmetric-key-ref?   leafref
          |     |        |             {keystore-supported}?
          |     |        +-- value?                      binary
          |     +-- cert?
          |     |       end-entity-cert-cms
          |     +---n certificate-expiration
          |     |  +-- expiration-date    yang:date-and-time
          |     +---x generate-certificate-signing-request
          |             {certificate-signing-request-generation}?
          |        +---w input
          |        |  +---w subject       binary
          |        |  +---w attributes?   binary
          |        +--ro output
          |           +--ro certificate-signing-request    ct:csr
          +--:(keystore) {keystore-supported}?
             +-- keystore-reference
                +-- asymmetric-key?   ks:asymmetric-key-ref
                +-- certificate?      leafref
     grouping keystore-grouping
       +-- asymmetric-keys
       |  +-- asymmetric-key* [name]
       |     +-- name?                                   string
       |     +-- public-key-format                       identityref
       |     +-- public-key                              binary
       |     +-- private-key-format?                     identityref
       |     +-- (private-key-type)
       |     |  +--:(private-key)
       |     |  |  +-- private-key?                      binary



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       |     |  +--:(hidden-private-key)
       |     |  |  +-- hidden-private-key?               empty
       |     |  +--:(encrypted-private-key)
       |     |     +-- encrypted-private-key
       |     |        +-- (key-type)
       |     |        |  +--:(symmetric-key-ref)
       |     |        |  |  +-- symmetric-key-ref?    leafref
       |     |        |  |          {keystore-supported}?
       |     |        |  +--:(asymmetric-key-ref)
       |     |        |     +-- asymmetric-key-ref?   leafref
       |     |        |             {keystore-supported}?
       |     |        +-- value?                      binary
       |     +-- certificates
       |     |  +-- certificate* [name]
       |     |     +-- name?                     string
       |     |     +-- cert                      end-entity-cert-cms
       |     |     +---n certificate-expiration
       |     |        +-- expiration-date    yang:date-and-time
       |     +---x generate-certificate-signing-request
       |             {certificate-signing-request-generation}?
       |        +---w input
       |        |  +---w subject       binary
       |        |  +---w attributes?   binary
       |        +--ro output
       |           +--ro certificate-signing-request    ct:csr
       +-- symmetric-keys
          +-- symmetric-key* [name]
             +-- name?                  string
             +-- key-format?            identityref
             +-- (key-type)
                +--:(key)
                |  +-- key?             binary
                +--:(hidden-key)
                |  +-- hidden-key?      empty
                +--:(encrypted-key)
                   +-- encrypted-key
                      +-- (key-type)
                      |  +--:(symmetric-key-ref)
                      |  |  +-- symmetric-key-ref?    leafref
                      |  |          {keystore-supported}?
                      |  +--:(asymmetric-key-ref)
                      |     +-- asymmetric-key-ref?   leafref
                      |             {keystore-supported}?
                      +-- value?                      binary







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3.2.  Example Usage

3.2.1.  A Keystore Instance

   The following example illustrates keys in <running>.  Please see
   Section 4 for an example illustrating built-in values in
   <operational>.

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

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

       <symmetric-key>
         <name>cleartext-symmetric-key</name>
         <key-format>ct:octet-string-key-format</key-format>
         <key>base64encodedvalue==</key>
       </symmetric-key>

       <symmetric-key>
         <name>hidden-symmetric-key</name>
         <hidden-key/>
       </symmetric-key>

       <symmetric-key>
         <name>encrypted-symmetric-key</name> <!-- operator's key -->
         <key-format>ct:encrypted-one-symmetric-key-format</key-format>
         <encrypted-key>
           <asymmetric-key-ref>hidden-asymmetric-key</asymmetric-key-re\
   f>
           <value>base64encodedvalue==</value>
         </encrypted-key>
       </symmetric-key>

     </symmetric-keys>
     <asymmetric-keys>

       <asymmetric-key>
         <name>ssh-rsa-key</name>
         <public-key-format>ct:ssh-public-key-format</public-key-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <private-key>base64encodedvalue==</private-key>
       </asymmetric-key>

       <asymmetric-key>



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         <name>ssh-rsa-key-with-cert</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <private-key>base64encodedvalue==</private-key>
         <certificates>
           <certificate>
             <name>ex-rsa-cert2</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
         </certificates>
       </asymmetric-key>

       <asymmetric-key>
         <name>raw-private-key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <private-key>base64encodedvalue==</private-key>
       </asymmetric-key>

       <asymmetric-key>
         <name>rsa-asymmetric-key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <private-key>base64encodedvalue==</private-key>
         <certificates>
           <certificate>
             <name>ex-rsa-cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
         </certificates>
       </asymmetric-key>

       <asymmetric-key>
         <name>ec-asymmetric-key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:ec-private-key-format</private-key-form\
   at>



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         <private-key>base64encodedvalue==</private-key>
         <certificates>
           <certificate>
             <name>ex-ec-cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
         </certificates>
       </asymmetric-key>

       <asymmetric-key>
         <name>hidden-asymmetric-key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <hidden-private-key/> <!-- e.g., TPM protected -->
         <certificates>
           <certificate>
             <name>builtin-idevid-cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
           <certificate>
             <name>my-ldevid-cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
         </certificates>
       </asymmetric-key>

       <asymmetric-key>
         <name>encrypted-asymmetric-key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:encrypted-one-asymmetric-key-format</pr\
   ivate-key-format>
         <encrypted-private-key>
           <symmetric-key-ref>encrypted-symmetric-key</symmetric-key-re\
   f>
           <value>base64encodedvalue==</value>
         </encrypted-private-key>
       </asymmetric-key>

     </asymmetric-keys>
   </keystore>








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3.2.2.  Notable Keystore Groupings

   The following non-normative module is used by subsequent examples to
   illustrate groupings defined in the ietf-keystore module.

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

     namespace "http://example.com/ns/example-keystore-usage";
     prefix "eku";

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

     organization
      "Example Corporation";

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

     description
      "This module illustrates the grouping in the keystore draft called
       'local-or-keystore-asymmetric-key-with-certs-grouping'.";

     revision "YYYY-MM-DD" {
       description
        "Initial version";
       reference
        "RFC XXXX: YANG Data Model for a 'Keystore' Mechanism";
     }

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

       list just-a-key {
         key name;
         leaf name {
           type string;
           description
             "An arbitrary name for this key.";
         }
         uses ks:local-or-keystore-asymmetric-key-grouping;
         description
           "An asymmetric key, with no certs, that may be configured



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            locally or be a reference to an asymmetric key in the
            keystore.  The intent is to reference just the asymmetric
            key, not any certificates that may also be associated
            with the asymmetric key.";
       }

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

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

   }

   The following example illustrates what two configured keys, one local
   and the other remote, might look like.  This example consistent with
   other examples above (i.e., the referenced key is in an example
   above).

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

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




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     <!-- ks:local-or-keystore-asymmetric-key-grouping -->

     <just-a-key>
       <name>a locally-defined key</name>
       <local-definition>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <private-key>base64encodedvalue==</private-key>
       </local-definition>
     </just-a-key>

     <just-a-key>
       <name>a keystore-defined key (and its associated certs)</name>
       <keystore-reference>rsa-asymmetric-key</keystore-reference>
     </just-a-key>

     <!-- ks:local-or-keystore-key-and-end-entity-cert-grouping -->

     <key-with-certs>
       <name>a locally-defined key with certs</name>
       <local-definition>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <private-key>base64encodedvalue==</private-key>
         <certificates>
           <certificate>
             <name>a locally-defined cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
         </certificates>
       </local-definition>
     </key-with-certs>

     <key-with-certs>
       <name>a keystore-defined key (and its associated certs)</name>
       <keystore-reference>rsa-asymmetric-key</keystore-reference>
     </key-with-certs>

     <!-- ks:local-or-keystore-end-entity-cert-with-key-grouping -->

     <end-entity-cert-with-key>
       <name>a locally-defined end-entity cert with key</name>



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       <local-definition>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <private-key-format>ct:rsa-private-key-format</private-key-for\
   mat>
         <private-key>base64encodedvalue==</private-key>
         <cert>base64encodedvalue==</cert>
       </local-definition>
     </end-entity-cert-with-key>

     <end-entity-cert-with-key>
       <name>a keystore-defined certificate (and its associated key)</n\
   ame>
       <keystore-reference>
         <asymmetric-key>rsa-asymmetric-key</asymmetric-key>
         <certificate>ex-rsa-cert</certificate>
       </keystore-reference>
     </end-entity-cert-with-key>

   </keystore-usage>

3.3.  YANG Module

   This YANG module has normative references to [RFC8341] and
   [I-D.ietf-netconf-crypto-types], and an informative reference to
   [RFC8342].

   <CODE BEGINS> file "ietf-keystore@2020-05-20.yang"

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

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

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

     organization



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       "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 a Keystore to centralize management
        of security credentials.

        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 CCCC
        (https://www.rfc-editor.org/info/rfcCCCC); see the RFC
        itself for full legal notices.

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

     revision 2020-05-20 {
       description
         "Initial version";
       reference
         "RFC CCCC: A YANG Data Model for a Keystore";
     }

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

     feature keystore-supported {
       description
         "The 'keystore-supported' feature indicates that the server
          supports the Keystore.";
     }



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

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

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

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

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


     grouping key-reference-type-grouping {
       description
         "A reusable grouping for a choice for the type of key
          referenced in the Keystore.";
       choice key-type {
         mandatory true;
         description
           "A choice between a reference to a symmetric or asymmetric
            key in the Keystore.";
         leaf symmetric-key-ref {
           if-feature "keystore-supported";
           type leafref {
             path "/ks:keystore/ks:symmetric-keys/ks:symmetric-key/"



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                  + "ks:name";
           }
           description
             "Identifies a symmetric key used to encrypt this key.";
         }
         leaf asymmetric-key-ref {
           if-feature "keystore-supported";
           type leafref {
             path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key/"
                  + "ks:name";
           }
           description
             "Identifies an asymmetric key used to encrypt this key.";
         }
       }
     }

     grouping encrypted-value-grouping {
       description
         "A reusable grouping for a value that has been encrypted by
          a symmetric or asymmetric key in the Keystore.";
       uses "key-reference-type-grouping";
       leaf value {
         type binary;
         description
           "The private key, encrypted using the specified symmetric
            or asymmetric key.";
       }
     }

     grouping symmetric-key-grouping {
       description
         "This grouping is identical to the one in ietf-crypto-types
          except that it adds a case statement enabling the key
          value to be encrypted by a symmetric or an asymmetric
          key known to the Keystore.";
       uses ct:symmetric-key-grouping {
         augment "key-type" {
           description
             "Augments a new 'case' statement into the 'choice'
              statement defined by the ietf-crypto-types module.";
           container encrypted-key {
             must "../key-format";
             description
               "A container for the encrypted symmetric key value.";
             uses encrypted-value-grouping;
           }
         }



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       }
     }

     grouping asymmetric-key-pair-grouping {
       description
         "This grouping is identical to the one in ietf-crypto-types
          except that it adds a case statement enabling the key
          value to be encrypted by a symmetric or an asymmetric
          key known to the Keystore.";
       uses ct:asymmetric-key-pair-grouping {
         augment "private-key-type" {
           description
             "Augments a new 'case' statement into the 'choice'
              statement defined by the ietf-crypto-types module.";
           container encrypted-private-key {
             must "../private-key-format";
             description
               "A container for the encrypted asymmetric private
                key value.";
             uses encrypted-value-grouping;
           }
         }
       }
     }

     grouping asymmetric-key-pair-with-cert-grouping {
       description
         "This grouping is identical to the one in ietf-crypto-types
          except that it adds a case statement enabling the key
          value to be encrypted by a symmetric or an asymmetric
          key known to the Keystore.";
       uses ct:asymmetric-key-pair-with-cert-grouping {
         augment "private-key-type" {
           description
             "Augments a new 'case' statement into the 'choice'
              statement defined by the ietf-crypto-types module.";
           container encrypted-private-key {
             must "../private-key-format";
             description
               "A container for the encrypted asymmetric private
                key value.";
             uses encrypted-value-grouping;
           }
         }
       }
     }

     grouping asymmetric-key-pair-with-certs-grouping {



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       description
         "This grouping is identical to the one in ietf-crypto-types
          except that it adds a case statement enabling the key
          value to be encrypted by a symmetric or an asymmetric
          key known to the Keystore.";
       uses ct:asymmetric-key-pair-with-certs-grouping {
         augment "private-key-type" {
           description
             "Augments a new 'case' statement into the 'choice'
              statement defined by the ietf-crypto-types module.";
           container encrypted-private-key {
             must "../private-key-format";
             description
               "A container for the encrypted asymmetric private
                key value.";
             uses encrypted-value-grouping;
           }
         }
       }
     }

     grouping asymmetric-key-certificate-ref-grouping {
       leaf asymmetric-key {
         type ks:asymmetric-key-ref;
         must '../certificate';
         description
           "A reference to an asymmetric key in the Keystore.";
       }
       leaf certificate {
         type leafref {
           path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key[ks:"
                + "name = current()/../asymmetric-key]/ks:certificates"
                + "/ks:certificate/ks:name";
         }
         must '../asymmetric-key';
         description
           "A reference to a specific certificate of the
            asymmetric key in the Keystore.";
       }
       description
         "This grouping defines a reference to a specific certificate
          associated with an asymmetric key stored in the Keystore.";
     }


     // local-or-keystore-* groupings

     grouping local-or-keystore-symmetric-key-grouping {



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       description
         "A grouping that expands to allow the symmetric key to be
          either stored locally, within the using data model, or be
          a reference to a symmetric key stored in the Keystore.";
       choice local-or-keystore {
         mandatory true;
         case local {
           if-feature "local-definitions-supported";
           container local-definition {
             description
               "Container to hold the local key definition.";
             uses symmetric-key-grouping;
           }
         }
         case keystore {
           if-feature "keystore-supported";
           leaf keystore-reference {
             type ks:symmetric-key-ref;
             description
               "A reference to an symmetric key that exists in
                the Keystore.";
           }
         }
         description
           "A choice between an inlined definition and a definition
            that exists in the Keystore.";
       }
     }

     grouping local-or-keystore-asymmetric-key-grouping {
       description
         "A grouping that expands to allow the asymmetric key to be
          either stored locally, within the using data model, or be
          a reference to an asymmetric key stored in the Keystore.";
       choice local-or-keystore {
         mandatory true;
         case local {
           if-feature "local-definitions-supported";
           container local-definition {
             description
               "Container to hold the local key definition.";
             uses asymmetric-key-pair-grouping;
           }
         }
         case keystore {
           if-feature "keystore-supported";
           leaf keystore-reference {
             type ks:asymmetric-key-ref;



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             description
               "A reference to an asymmetric key that exists in
                the Keystore.  The intent is to reference just the
                asymmetric key without any regard for any certificates
                that may be associated with it.";
           }
         }
         description
           "A choice between an inlined definition and a definition
            that exists in the Keystore.";
       }
     }

     grouping local-or-keystore-asymmetric-key-with-certs-grouping {
       description
         "A grouping that expands to allow an asymmetric key and its
          associated certificates to be either stored locally, within
          the using data model, or be a reference to an asymmetric key
          (and its associated certificates) stored in the Keystore.";
       choice local-or-keystore {
         mandatory true;
         case local {
           if-feature "local-definitions-supported";
           container local-definition {
             description
               "Container to hold the local key definition.";
             uses asymmetric-key-pair-with-certs-grouping;
           }
         }
         case keystore {
           if-feature "keystore-supported";
           leaf keystore-reference {
             type ks:asymmetric-key-ref;
             description
               "A reference to an asymmetric-key (and all of its
                associated certificates) in the Keystore.";
           }
         }
         description
           "A choice between an inlined definition and a definition
            that exists in the Keystore.";
       }
     }

     grouping local-or-keystore-end-entity-cert-with-key-grouping {
       description
         "A grouping that expands to allow an end-entity certificate
          (and its associated private key) to be either stored locally,



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          within the using data model, or be a reference to a specific
          certificate in the Keystore.";
       choice local-or-keystore {
         mandatory true;
         case local {
           if-feature "local-definitions-supported";
           container local-definition {
             description
               "Container to hold the local key definition.";
             uses asymmetric-key-pair-with-cert-grouping;
           }
         }
         case keystore {
           if-feature "keystore-supported";
           container keystore-reference {
             uses asymmetric-key-certificate-ref-grouping;
             description
               "A reference to a specific certificate (and its
                associated private key) in the Keystore.";
           }
         }
         description
           "A choice between an inlined definition and a definition
            that exists in the Keystore.";
       }
     }

     grouping keystore-grouping {
       description
         "Grouping definition enables use in other contexts.  If ever
          done, implementations SHOULD augment new 'case' statements
          into local-or-keystore 'choice' statements to supply leafrefs
          to the new location.";
       container asymmetric-keys {
         description
           "A list of asymmetric keys.";
         list asymmetric-key {
           key "name";
           description
             "An asymmetric key.";
           leaf name {
             type string;
             description
               "An arbitrary name for the asymmetric key.";
           }
           uses ks:asymmetric-key-pair-with-certs-grouping;
         }
       }



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       container symmetric-keys {
         description
           "A list of symmetric keys.";
         list symmetric-key {
           key "name";
           description
             "A symmetric key.";
           leaf name {
             type string;
             description
               "An arbitrary name for the symmetric key.";
           }
           uses ks:symmetric-key-grouping;
         }
       }
     } // grouping keystore-grouping


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

     container keystore {
       nacm:default-deny-write;
       description
         "The Keystore contains a list of symmetric keys and a list
          of asymmetric keys.";
       uses keystore-grouping;
     }

   }

   <CODE ENDS>

4.  Support for Built-in Keys

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

   The key characteristic of the built-in keys is that they are provided
   by the system, as opposed to configuration.  As such, they are
   present in <operational>.  The example below illustrates what the
   truststore in <operational> might look like for a server in its
   factory default state.





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

   <keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types"
     xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
     or:origin="or:intended">
     <asymmetric-keys>
       <asymmetric-key or:origin="or:system">
         <name>Manufacturer-Generated Hidden Key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <hidden-private-key/> <!-- e.g., TPM protected -->
         <certificates>
           <certificate>
             <name>Manufacturer-Generated IDevID Cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
         </certificates>
       </asymmetric-key>
     </asymmetric-keys>
   </keystore>

   In order for the built-in keys to be referenced by configuration, the
   referenced nodes MUST first be copied into <running>.  They SHOULD be
   copied into <running> using the same "key" values, so that the system
   can bind the references to the built-in entries.  Only the referenced
   nodes need to be copied.  When using the same key values as in
   <operational> no new values can be added and no existing values can
   be changed; that which is in <running> can only be a subset of that
   which is in <operational>.

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
















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

   <keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
     <asymmetric-keys>
       <asymmetric-key>
         <name>Manufacturer-Generated Hidden Key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <hidden-private-key/> <!-- e.g., TPM protected -->
         <certificates>
           <certificate>
             <name>Manufacturer-Generated IDevID Cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
           <certificate>
             <name>Deployment-Specific LDevID Cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
         </certificates>
       </asymmetric-key>
     </asymmetric-keys>
   </keystore>

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
























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

   <keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
     xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types"
     xmlns:or="urn:ietf:params:xml:ns:yang:ietf-origin"
     or:origin="or:intended">
     <asymmetric-keys>
       <asymmetric-key or:origin="or:system">
         <name>Manufacturer-Generated Hidden Key</name>
         <public-key-format>ct:subject-public-key-info-format</public-k\
   ey-format>
         <public-key>base64encodedvalue==</public-key>
         <hidden-private-key/> <!-- e.g., TPM protected -->
         <certificates>
           <certificate>
             <name>Manufacturer-Generated IDevID Cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
           <certificate or:origin="or:intended">
             <name>Deployment-Specific LDevID Cert</name>
             <cert>base64encodedvalue==</cert>
           </certificate>
         </certificates>
       </asymmetric-key>
     </asymmetric-keys>
   </keystore>

5.  Encrypting Keys in Configuration

   This section describes an approach that enables all the private keys
   on a server to be encrypted, such that traditional backup/restore
   procedures can be used without concern for keys being compromised
   when in transit.

5.1.  Root Key

   The cornerstone to this solution is the existence of a "root" key
   that can be used to encrypt all the other keys.  The server MUST be
   able to use this key to decrypt the other keys in the configuration.

   The root key SHOULD be a hidden key, i.e., one whose private data has
   no presence in <running> or <operational> (see "hidden-key" and
   "hidden-private-key" in "ietf-crypto-types"
   [I-D.ietf-netconf-crypto-types]).  If the server implementation does
   not support hidden keys, then the private data part of key MUST be
   protected by access control with access granted only to an
   administrator with special access control rights (e.g., an




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   organization's crypto officer).  Given the long lifetime of built-in
   keys (see Section 4), built-in keys MUST be hidden.

   A hidden root key MAY be either a symmetric key or an asymmetric key.
   If the hidden root key is symmetric, then the server MUST provide
   APIs enabling other keys (ideally generated by the server) to be
   encrypted.  If the hidden root key is asymmetric, then the server
   SHOULD provide APIs enabling other keys to be both generated and
   encrypted by it, but MAY alternatively enable administrators with
   special access control rights to generate and encrypt the other keys
   themselves, using the hidden key's public part.  For practical
   reasons, an unhidden root key SHOULD be asymmetric, so that its
   public part can be accessed by other administrators without concern.

5.2.  Configuring Encrypting Keys

   Each time a new key is to be configured, it SHOULD be encrypted by
   the root key.

   In "ietf-crypto-types" [I-D.ietf-netconf-crypto-types], the format
   for an encrypted symmetric key is described by the "encrypted-one-
   symmetric-key-format" identity, while the format for an encrypted
   asymmetric key is described by the "encrypted-one-asymmetric-key-
   format" identity

   Ideally, the server implementation provides an API to generate a
   symmetric or asymmetric key, and encrypt the generated key using
   another key known to the system (e.g., the root key).  Thusly
   administrators can safely call this API to configure new keys.

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

   In either case, the encrypted key can be configured into the Keystore
   using either the "encrypted-key" (for symmetric keys) or the
   "encrypted-private-key" (for asymmetric keys) nodes.  These two nodes
   contain both the encrypted value as well as a reference to the other
   key in the Keystore that it was encrypted by.

5.3.  Migrating Configuration to Another Server

   One concern that arose during discourse was how it could be possible
   migrate configuration from one server to another server, if both
   servers used different root keys (e.g., a TPM-protected built-in
   key).  It was noted that, in this case, the second server would be
   unable to decrypt any of the keys encrypted by the first server.




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   The solution to this issue is simply to ensure that the same key is
   known to both servers.  How this is achieved may vary.  If the first
   server is still accessible, it may be possible to ask it to encrypt
   the key using the second server's root key.  That said, a common
   scenario for needing to migrate configuration to another server is
   because the first server is no longer available.  Thus it is more
   likely the case that the shared root key is known to administrators
   with special access control rights (an organization's crypto
   officer), such that the shared key can be provided to the second
   server to unlock all the other keys in the configuration.

   For systems that have a built-in key protected by hardware, the
   shared root key SHOULD be encrypted by the built-in key.  In this
   way, at least from the system's perspective, it is more like an
   intermediate key than a root key.

   As a concrete example, assuming both servers have built-in asymmetric
   keys, the shared key could be a symmetric key that an organization's
   crypto officer encrypts offline knowing each server's public key,
   which may be, e.g., in the server's IDevID certificate.  The crypto
   officer can then safely handoff the encrypted shared key to other
   administrators responsible for server installations, including
   migrations.

   In order to migrate a configuration, the administrator would need to
   make just a single modification to the configuration before loading
   it onto the second server, which is to replace the shared key's
   Keystore entry from the first server (an encrypted key), with the
   shared key encrypted by the second server's built-in key.

6.  Security Considerations

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

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

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




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   effect on network operations.  These are the subtrees and data nodes
   and their sensitivity/vulnerability:

      /: The entire data tree defined by this module is sensitive to
         write operations.  For instance, the addition or removal of
         keys, certificates, etc., can dramatically alter the
         implemented security policy.  For this reason, the NACM
         extension "default-deny-write" has been set for the entire data
         tree.

      /keystore/asymmetric-keys/asymmetric-key/private-key:  When
         writing this node, implementations MUST 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, and
         alert the client that the strength of the key may have been
         compromised.  Additionally, when deleting this node,
         implementations SHOULD automatically (without explicit request)
         zeroize these keys in the most secure manner available, so as
         to prevent the remnants of their persisted storage locations
         from being analyzed in any meaningful way.

   Some of the readable data nodes 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:

      /keystore/asymmetric-keys/asymmetric-key/private-key:  This node
         is additionally sensitive to read operations such that, in
         normal use cases, it should never be returned to a client.  The
         best reason for returning this node is to support backup/
         restore type workflows.  For this reason, the NACM extension
         "default-deny-all" has been set for this data node.

7.  IANA Considerations

7.1.  The IETF XML Registry

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

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



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7.2.  The YANG Module Names Registry

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

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


8.  References

8.1.  Normative References

   [I-D.ietf-netconf-crypto-types]
              Watsen, K. and H. Wang, "Common YANG Data Types for
              Cryptography", draft-ietf-netconf-crypto-types-14 (work in
              progress), March 2020.

   [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>.

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

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

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

8.2.  Informative References

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






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   [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>.

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

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

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

   [Std-802.1AR-2009]
              Group, W. -. H. L. L. P. W., "IEEE Standard for Local and
              metropolitan area networks - Secure Device Identity",
              December 2009, <http://standards.ieee.org/findstds/
              standard/802.1AR-2009.html>.

8.3.  URIs

   [1] https://tools.ietf.org/html/draft-ietf-netconf-crypto-types

   [2] https://tools.ietf.org/html/draft-ietf-netconf-trust-anchors

   [3] https://tools.ietf.org/html/draft-ietf-netconf-keystore

   [4] https://tools.ietf.org/html/draft-ietf-netconf-tcp-client-server

   [5] https://tools.ietf.org/html/draft-ietf-netconf-ssh-client-server

   [6] https://tools.ietf.org/html/draft-ietf-netconf-tls-client-server

   [7] https://tools.ietf.org/html/draft-ietf-netconf-http-client-server

   [8] https://tools.ietf.org/html/draft-ietf-netconf-netconf-client-
       server





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   [9] https://tools.ietf.org/html/draft-ietf-netconf-restconf-client-
       server

















































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Appendix A.  Change Log

A.1.  00 to 01

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

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

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

A.2.  01 to 02

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

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

   o  Fixed up a few description statements.

A.3.  02 to 03

   o  Changed draft's title.

   o  Added missing references.

   o  Collapsed sections and levels.

   o  Added RFC 8174 to Requirements Language Section.

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

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

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

A.4.  03 to 04

   o  Added typedefs around leafrefs to common keystore paths

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

   o  Removed Design Considerations section

   o  Moved key and certificate definitions from data tree to groupings




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A.5.  04 to 05

   o  Removed trust anchors (now in their own draft)

   o  Added back global keystore structure

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

A.6.  05 to 06

   o  Added feature "local-keys-supported"

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

   o  Renamed generate-asymmetric-key to generate-hidden-key

   o  Added an install-hidden-key action

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

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

A.7.  06 to 07

   o  Removed a "require-instance false"

   o  Clarified some description statements

   o  Improved the keystore-usage examples

A.8.  07 to 08

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

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

A.9.  08 to 09

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





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

A.10.  09 to 10

   o  Updated draft title to match new truststore draft title

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

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

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

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

A.11.  10 to 11

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

   o  Added feature feature 'key-generation'.

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

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

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

A.12.  11 to 12

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





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

   o  Updated the Introduction section.

A.13.  12 to 13

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

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

A.14.  13 to 14

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

A.15.  14 to 15

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

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

   o  Added local-or-keystore-symmetric-key-grouping for PSK support.

A.16.  15 to 16

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

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

A.17.  16 to 17

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

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

   o  Removed the "algorithm" nodes from remaining examples.

   o  Renamed/updated the "Support for Built-in Keys" section.

   o  Added new section "Encrypting Keys in Configuration".



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

Acknowledgements

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

Author's Address

   Kent Watsen
   Watsen Networks

   EMail: kent+ietf@watsen.net


































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