A YANG Data Model for a Keystore
draft-ietf-netconf-keystore-22
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Active Internet-Draft (netconf WG)
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Kent Watsen
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2021-05-18
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draft-ietf-netconf-system-keychain
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Internet Engineering Task Force (IETF)
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(None)
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Yang Validation |
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☯
0 errors, 0 warnings.
draft-ietf-netconf-keystore-22.txt:
xym 0.5:
Extracting 'ex-keystore-usage'
Getting YANG file name from module name: ex-keystore-usage.yang
Extracting 'ietf-keystore@2021-05-18.yang'
Removed 0 empty lines
ietf-keystore@2021-05-18.yang:
pyang 2.4.0: pyang --verbose --ietf -p {libs} {model}:
# module search path: a/www/ietf-ftp/yang/rfcmod/:/a/www/ietf-ftp/yang/draftmod/:/a/www/ietf-ftp/yang/ianamod/:/a/www/ietf-ftp/yang/catalogmod/:.:/var/lib/wwwrun/yang/modules:/a/www/ietf-datatracker/7.31.0/env/share/yang/modules
# read ietf-keystore@2021-05-18.yang (CL)
# read /a/www/ietf-datatracker/7.31.0/env/share/yang/modules/ietf/ietf-netconf-acm.yang
# read /a/www/ietf-ftp/yang/rfcmod/ietf-netconf-acm@2018-02-14.yang
# read /a/www/ietf-datatracker/7.31.0/env/share/yang/modules/ietf/ietf-yang-types.yang
# read /a/www/ietf-ftp/yang/draftmod/ietf-yang-types@2021-04-14.yang
# read /a/www/ietf-ftp/yang/draftmod/ietf-crypto-types@2021-05-18.yang
yanglint SO 1.6.7: yanglint --verbose -p {tmplib} -p {rfclib} -p {draftlib} -p {ianalib} -p {cataloglib} {model} -i:
No validation errors
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NETCONF Working Group K. Watsen
Internet-Draft Watsen Networks
Intended status: Standards Track 18 May 2021
Expires: 19 November 2021
A YANG Data Model for a Keystore
draft-ietf-netconf-keystore-22
Abstract
This document defines a YANG module called "ietf-keystore" that
enables centralized configuration of both symmetric and asymmetric
keys. The secret value for both key types may be encrypted or
hidden. Asymmetric keys may be associated with certificates.
Notifications are sent when certificates are about to expire.
Editorial Note (To be removed by RFC Editor)
This draft contains placeholder values that need to be replaced with
finalized values at the time of publication. This note summarizes
all of the substitutions that are needed. No other RFC Editor
instructions are specified elsewhere in this document.
Artwork in this document contains shorthand references to drafts in
progress. Please apply the following replacements:
* "AAAA" --> the assigned RFC value for draft-ietf-netconf-crypto-
types
* "CCCC" --> the assigned RFC value for this draft
Artwork in this document contains placeholder values for the date of
publication of this draft. Please apply the following replacement:
* "2021-05-18" --> 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.
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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 19 November 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 . . . . . . . . . . . . . . . . . 4
1.2. Specification Language . . . . . . . . . . . . . . . . . 6
1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6
1.4. Adherence to the NMDA . . . . . . . . . . . . . . . . . . 6
2. The "ietf-keystore" Module . . . . . . . . . . . . . . . . . 6
2.1. Data Model Overview . . . . . . . . . . . . . . . . . . . 6
2.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 14
2.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 26
3. Support for Built-in Keys . . . . . . . . . . . . . . . . . . 34
4. Encrypting Keys in Configuration . . . . . . . . . . . . . . 37
5. Security Considerations . . . . . . . . . . . . . . . . . . . 41
5.1. Security of Data at Rest . . . . . . . . . . . . . . . . 41
5.2. Unconstrained Private Key Usage . . . . . . . . . . . . . 41
5.3. The "ietf-keystore" YANG Module . . . . . . . . . . . . . 41
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 42
6.1. The "IETF XML" Registry . . . . . . . . . . . . . . . . . 42
6.2. The "YANG Module Names" Registry . . . . . . . . . . . . 42
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 42
7.1. Normative References . . . . . . . . . . . . . . . . . . 42
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7.2. Informative References . . . . . . . . . . . . . . . . . 43
Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 45
A.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 45
A.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 45
A.3. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 45
A.4. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 46
A.5. 04 to 05 . . . . . . . . . . . . . . . . . . . . . . . . 46
A.6. 05 to 06 . . . . . . . . . . . . . . . . . . . . . . . . 46
A.7. 06 to 07 . . . . . . . . . . . . . . . . . . . . . . . . 46
A.8. 07 to 08 . . . . . . . . . . . . . . . . . . . . . . . . 47
A.9. 08 to 09 . . . . . . . . . . . . . . . . . . . . . . . . 47
A.10. 09 to 10 . . . . . . . . . . . . . . . . . . . . . . . . 47
A.11. 10 to 11 . . . . . . . . . . . . . . . . . . . . . . . . 47
A.12. 11 to 12 . . . . . . . . . . . . . . . . . . . . . . . . 48
A.13. 12 to 13 . . . . . . . . . . . . . . . . . . . . . . . . 48
A.14. 13 to 14 . . . . . . . . . . . . . . . . . . . . . . . . 48
A.15. 14 to 15 . . . . . . . . . . . . . . . . . . . . . . . . 48
A.16. 15 to 16 . . . . . . . . . . . . . . . . . . . . . . . . 48
A.17. 16 to 17 . . . . . . . . . . . . . . . . . . . . . . . . 49
A.18. 17 to 18 . . . . . . . . . . . . . . . . . . . . . . . . 49
A.19. 18 to 19 . . . . . . . . . . . . . . . . . . . . . . . . 49
A.20. 19 to 20 . . . . . . . . . . . . . . . . . . . . . . . . 49
A.21. 20 to 21 . . . . . . . . . . . . . . . . . . . . . . . . 50
A.22. 21 to 22 . . . . . . . . . . . . . . . . . . . . . . . . 50
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 50
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 50
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 or hidden (see [I-D.ietf-netconf-crypto-types]. Asymmetric
keys may be associated with certificates. Notifications are sent
when certificates are about to expire.
The "ietf-keystore" module defines many "grouping" statements
intended for use by other modules that may import it. For instance,
there are groupings that define enabling a key to be either
configured locally (within the defining data model) or be a reference
to a key in the keystore.
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Special consideration has been given for systems that have
cryptographic hardware, such as a Trusted Platform Module (TPM).
These systems are unique in that the cryptographic hardware hides the
secret key values. Additionally, such hardware is commonly
initialized when manufactured to protect a "built-in" asymmetric key
for which the public half is conveyed in an identity certificate
(e.g., an IDevID [Std-802.1AR-2009] certificate). Please see
Section 3 to see how built-in keys are supported.
This document intends to support existing practices; it does not
intend to define new behavior for systems to implement. To simplify
implementation, advanced key formats may be selectively implemented.
Implementations may utilize zero or more operating system level
keystore utilities and/or hardware security modules (HSMs).
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. Terminology
The terms "client" and "server" are defined in [RFC6241] and are not
redefined here.
The term "keystore" is defined in this draft as a mechanism that
intends safeguard secrets placed into it for protection.
The nomenclature "<running>" and "<operational>" are defined in
[RFC8342].
The sentence fragments "augmented" and "augmented in" are used herein
as the past tense verbified form of the "augment" statement defined
in Section 7.17 of [RFC7950].
1.4. Adherence to the NMDA
This document is compliant with Network Management Datastore
Architecture (NMDA) [RFC8342]. For instance, keys and associated
certificates installed during manufacturing (e.g., for an IDevID
certificate) are expected to appear in <operational> (see Section 3).
2. The "ietf-keystore" Module
This section defines a YANG 1.1 [RFC7950] module called "ietf-
keystore". A high-level overview of the module is provided in
Section 2.1. Examples illustrating the module's use are provided in
Section 2.2. The YANG module itself is defined in Section 2.3.
2.1. Data Model Overview
This section provides an overview of the "ietf-keystore" module in
terms of its features, typedefs, groupings, and protocol-accessible
nodes.
2.1.1. Features
The following diagram lists all the "feature" statements defined in
the "ietf-keystore" module:
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Features:
+-- central-keystore-supported
+-- local-definitions-supported
| The diagram above uses syntax that is similar to but not
| defined in [RFC8340].
2.1.2. Typedefs
The following diagram lists the "typedef" statements defined in the
"ietf-keystore" module:
Typedefs:
leafref
+-- symmetric-key-ref
+-- asymmetric-key-ref
| The diagram above uses syntax that is similar to but not
| defined in [RFC8340].
Comments:
* All of the typedefs defined in the "ietf-keystore" module extend
the base "leafref" type defined in [RFC7950].
* The leafrefs refer to symmetric and asymmetric keys in the central
keystore, when this module is implemented.
* These typedefs are provided as an aid to downstream modules that
import the "ietf-keystore" module.
2.1.3. Groupings
The "ietf-keystore" module defines the following "grouping"
statements:
* encrypted-by-choice-grouping
* asymmetric-key-certificate-ref-grouping
* local-or-keystore-symmetric-key-grouping
* local-or-keystore-asymmetric-key-grouping
* local-or-keystore-asymmetric-key-with-certs-grouping
* local-or-keystore-end-entity-cert-with-key-grouping
* keystore-grouping
Each of these groupings are presented in the following subsections.
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2.1.3.1. The "encrypted-by-choice-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "encrypted-by-
choice-grouping" grouping:
| The grouping's name is intended to be parsed "(encrypted-
| by)-(choice)-(grouping)", not as "(encrypted)-(by-
| choice)-(grouping)".
grouping encrypted-by-choice-grouping
+-- (encrypted-by-choice)
+--:(symmetric-key-ref)
| +-- symmetric-key-ref? ks:symmetric-key-ref
+--:(asymmetric-key-ref)
+-- asymmetric-key-ref? ks:asymmetric-key-ref
Comments:
* This grouping defines a "choice" statement with options to
reference either a symmetric or an asymmetric key configured in
the keystore.
* This grouping is usable only when the keystore module is
implemented. Servers defining custom keystore locations MUST
augment in alternate "encrypted-by" references to the alternate
locations.
2.1.3.2. The "asymmetric-key-certificate-ref-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "asymmetric-key-
certificate-ref-grouping" grouping:
grouping asymmetric-key-certificate-ref-grouping
+-- asymmetric-key? ks:asymmetric-key-ref
+-- certificate? leafref
Comments:
* This grouping defines a reference to a certificate in two parts:
the first being the name of the asymmetric key the certificate is
associated with, and the second being the name of the certificate
itself.
* This grouping is usable only when the keystore module is
implemented. Servers defining custom keystore locations MAY
define an alternate grouping for references to the alternate
locations.
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2.1.3.3. The "local-or-keystore-symmetric-key-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "local-or-
keystore-symmetric-key-grouping" grouping:
grouping local-or-keystore-symmetric-key-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +---u ct:symmetric-key-grouping
+--:(keystore) {central-keystore-supported}?
+-- keystore-reference? ks:symmetric-key-ref
Comments:
* The "local-or-keystore-symmetric-key-grouping" grouping is
provided soley as convenience to downstream modules that wish to
offer an option for whether a symmetric key is defined locally or
as a reference to a symmetric key in the keystore.
* A "choice" statement is used to expose the various options. Each
option is enabled by a "feature" statement. Additional "case"
statements MAY be augmented in if, e.g., there is a need to
reference a symmetric key in an alternate location.
* For the "local-definition" option, the definition uses the
"symmetric-key-grouping" grouping discussed in Section 2.1.4.3 of
[I-D.ietf-netconf-crypto-types].
* For the "keystore" option, the "keystore-reference" is an instance
of the "symmetric-key-ref" discussed in Section 2.1.2.
2.1.3.4. The "local-or-keystore-asymmetric-key-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "local-or-
keystore-asymmetric-key-grouping" grouping:
grouping local-or-keystore-asymmetric-key-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +---u ct:asymmetric-key-pair-grouping
+--:(keystore) {central-keystore-supported}?
+-- keystore-reference? ks:asymmetric-key-ref
Comments:
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* The "local-or-keystore-asymmetric-key-grouping" grouping is
provided soley as convenience to downstream modules that wish to
offer an option for whether an asymmetric key is defined locally
or as a reference to an asymmetric key in the keystore.
* A "choice" statement is used to expose the various options. Each
option is enabled by a "feature" statement. Additional "case"
statements MAY be augmented in if, e.g., there is a need to
reference an asymmetric key in an alternate location.
* For the "local-definition" option, the definition uses the
"asymmetric-key-pair-grouping" grouping discussed in
Section 2.1.4.5 of [I-D.ietf-netconf-crypto-types].
* For the "keystore" option, the "keystore-reference" is an instance
of the "asymmetric-key-ref" typedef discussed in Section 2.1.2.
2.1.3.5. The "local-or-keystore-asymmetric-key-with-certs-grouping"
Grouping
The following tree diagram [RFC8340] illustrates the "local-or-
keystore-asymmetric-key-with-certs-grouping" grouping:
grouping local-or-keystore-asymmetric-key-with-certs-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +---u ct:asymmetric-key-pair-with-certs-grouping
+--:(keystore) {central-keystore-supported}?
+-- keystore-reference? ks:asymmetric-key-ref
Comments:
* The "local-or-keystore-asymmetric-key-with-certs-grouping"
grouping is provided soley as convenience to downstream modules
that wish to offer an option for whether an asymmetric key is
defined locally or as a reference to an asymmetric key in the
keystore.
* A "choice" statement is used to expose the various options. Each
option is enabled by a "feature" statement. Additional "case"
statements MAY be augmented in if, e.g., there is a need to
reference an asymmetric key in an alternate location.
* For the "local-definition" option, the definition uses the
"asymmetric-key-pair-with-certs-grouping" grouping discussed in
Section 2.1.4.11 of [I-D.ietf-netconf-crypto-types].
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* For the "keystore" option, the "keystore-reference" is an instance
of the "asymmetric-key-ref" typedef discussed in Section 2.1.2.
2.1.3.6. The "local-or-keystore-end-entity-cert-with-key-grouping"
Grouping
The following tree diagram [RFC8340] illustrates the "local-or-
keystore-end-entity-cert-with-key-grouping" grouping:
grouping local-or-keystore-end-entity-cert-with-key-grouping
+-- (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +-- local-definition
| +---u ct:asymmetric-key-pair-with-cert-grouping
+--:(keystore) {central-keystore-supported}?
+-- keystore-reference
+---u asymmetric-key-certificate-ref-grouping
Comments:
* The "local-or-keystore-end-entity-cert-with-key-grouping" grouping
is provided soley as convenience to downstream modules that wish
to offer an option for whether a symmetric key is defined locally
or as a reference to a symmetric key in the keystore.
* A "choice" statement is used to expose the various options. Each
option is enabled by a "feature" statement. Additional "case"
statements MAY be augmented in if, e.g., there is a need to
reference a symmetric key in an alternate location.
* For the "local-definition" option, the definition uses the
"asymmetric-key-pair-with-certs-grouping" grouping discussed in
Section 2.1.4.11 of [I-D.ietf-netconf-crypto-types].
* For the "keystore" option, the "keystore-reference" uses the
"asymmetric-key-certificate-ref-grouping" grouping discussed in
Section 2.1.3.2.
2.1.3.7. The "keystore-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "keystore-
grouping" grouping:
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grouping keystore-grouping
+-- asymmetric-keys
| +-- asymmetric-key* [name]
| +-- name? string
| +---u ct:asymmetric-key-pair-with-certs-grouping
+-- symmetric-keys
+-- symmetric-key* [name]
+-- name? string
+---u ct:symmetric-key-grouping
Comments:
* The "keystore-grouping" grouping defines a keystore instance as
being composed of symmetric and asymmetric keys. The structure
for the symmetric and asymmetric keys is essentially the same,
being a "list" inside a "container".
* For asymmetric keys, each "asymmetric-key" uses the "asymmetric-
key-pair-with-certs-grouping" grouping discussed in
Section 2.1.4.11 of [I-D.ietf-netconf-crypto-types].
* For symmetric keys, each "symmetric-key" uses the "symmetric-key-
grouping" grouping discussed in Section 2.1.4.3 of
[I-D.ietf-netconf-crypto-types].
2.1.4. Protocol-accessible Nodes
The following tree diagram [RFC8340] lists all the protocol-
accessible nodes defined in the "ietf-keystore" module, without
expanding the "grouping" statements:
module: ietf-keystore
+--rw keystore
+---u keystore-grouping
The following tree diagram [RFC8340] lists all the protocol-
accessible nodes defined in the "ietf-keystore" module, with all
"grouping" statements expanded, enabling the keystore's full
structure to be seen:
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
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| +--rw (private-key-type)
| | +--:(cleartext-private-key)
| | | +--rw cleartext-private-key? binary
| | +--:(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?
| | | | ks:symmetric-key-ref
| | | +--:(asymmetric-key-ref)
| | | +--rw asymmetric-key-ref?
| | | ks:asymmetric-key-ref
| | +--rw encrypted-value-format identityref
| | +--rw encrypted-value binary
| +--rw certificates
| | +--rw certificate* [name]
| | +--rw name string
| | +--rw cert-data end-entity-cert-cms
| | +---n certificate-expiration
| | {certificate-expiration-notification}?
| | +-- expiration-date yang:date-and-time
| +---x generate-certificate-signing-request
| {certificate-signing-request-generation}?
| +---w input
| | +---w csr-info ct:csr-info
| +--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)
+--:(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?
| | ks:symmetric-key-ref
| +--:(asymmetric-key-ref)
| +--rw asymmetric-key-ref?
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| ks:asymmetric-key-ref
+--rw encrypted-value-format identityref
+--rw encrypted-value binary
Comments:
* Protocol-accessible nodes are those nodes that are accessible when
the module is "implemented", as described in Section 5.6.5 of
[RFC7950].
* The protocol-accessible nodes for the "ietf-keystore" module are
an instance of the "keystore-grouping" grouping discussed in
Section 2.1.3.7.
* The reason for why "keystore-grouping" exists separate from the
protocol-accessible nodes definition is so as to enable instances
of the keystore to be instantiated in other locations, as may be
needed or desired by some modules.
2.2. Example Usage
The examples in this section are encoded using XML, such as might be
the case when using the NETCONF protocol. Other encodings MAY be
used, such as JSON when using the RESTCONF protocol.
2.2.1. A Keystore Instance
The following example illustrates keys in <running>. Please see
Section 3 for an example illustrating built-in values in
<operational>.
=============== NOTE: '\' line wrapping per RFC 8792 ================
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
<symmetric-keys>
<symmetric-key>
<name>cleartext-symmetric-key</name>
<key-format>ct:octet-string-key-format</key-format>
<cleartext-key>base64encodedvalue==</cleartext-key>
</symmetric-key>
<symmetric-key>
<name>hidden-symmetric-key</name>
<hidden-key/>
</symmetric-key>
<symmetric-key>
<name>encrypted-symmetric-key</name>
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<key-format>ct:one-symmetric-key-format</key-format>
<encrypted-key>
<encrypted-by>
<asymmetric-key-ref>hidden-asymmetric-key</asymmetric-k\
ey-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>
<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-format>
<cleartext-private-key>base64encodedvalue==</cleartext-priv\
ate-key>
</asymmetric-key>
<asymmetric-key>
<name>ssh-rsa-key-with-cert</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-priv\
ate-key>
<certificates>
<certificate>
<name>ex-rsa-cert2</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key>
<name>raw-private-key</name>
<public-key-format>
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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-priv\
ate-key>
</asymmetric-key>
<asymmetric-key>
<name>rsa-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-priv\
ate-key>
<certificates>
<certificate>
<name>ex-rsa-cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key>
<name>ec-asymmetric-key</name>
<public-key-format>
ct:subject-public-key-info-format
</public-key-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>
ct:ec-private-key-format
</private-key-format>
<cleartext-private-key>base64encodedvalue==</cleartext-priv\
ate-key>
<certificates>
<certificate>
<name>ex-ec-cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key>
<name>hidden-asymmetric-key</name>
<public-key-format>
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ct:subject-public-key-info-format
</public-key-format>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/>
<certificates>
<certificate>
<name>builtin-idevid-cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
<certificate>
<name>my-ldevid-cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
</certificates>
</asymmetric-key>
<asymmetric-key>
<name>encrypted-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>
<encrypted-private-key>
<encrypted-by>
<symmetric-key-ref>encrypted-symmetric-key</symmetric-k\
ey-ref>
</encrypted-by>
<encrypted-value-format>
ct:cms-encrypted-data-format
</encrypted-value-format>
<encrypted-value>base64encodedvalue==</encrypted-value>
</encrypted-private-key>
</asymmetric-key>
</asymmetric-keys>
</keystore>
2.2.2. A Certificate Expiration Notification
The following example illustrates a "certificate-expiration"
notification for a certificate associated with a key configured in
the keystore.
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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>
<keystore xmlns="urn:ietf:params:xml:ns:yang:ietf-keystore">
<asymmetric-keys>
<asymmetric-key>
<name>hidden-asymmetric-key</name>
<certificates>
<certificate>
<name>my-ldevid-cert</name>
<certificate-expiration>
<expiration-date>2018-08-05T14:18:53-05:00</expiration\
-date>
</certificate-expiration>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
</notification>
2.2.3. The "Local or Keystore" Groupings
This section illustrates the various "local-or-keystore" groupings
defined in the "ietf-keystore" module, specifically the "local-or-
keystore-symmetric-key-grouping" (Section 2.1.3.3), "local-or-
keystore-asymmetric-key-grouping" (Section 2.1.3.4), "local-or-
keystore-asymmetric-key-with-certs-grouping" (Section 2.1.3.5), and
"local-or-keystore-end-entity-cert-with-key-grouping"
(Section 2.1.3.6) groupings.
These examples assume the existence of an example module called "ex-
keystore-usage" having the namespace "http://example.com/ns/example-
keystore-usage".
The ex-keystore-usage module is first presented using tree diagrams
[RFC8340], followed by an instance example illustrating all the
"local-or-keystore" groupings in use, followed by the YANG module
itself.
The following tree diagram illustrates "ex-keystore-usage" without
expanding the "grouping" statements:
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module: ex-keystore-usage
+--rw keystore-usage
+--rw symmetric-key* [name]
| +--rw name string
| +---u ks:local-or-keystore-symmetric-key-grouping
+--rw asymmetric-key* [name]
| +--rw name string
| +---u ks:local-or-keystore-asymmetric-key-grouping
+--rw asymmetric-key-with-certs* [name]
| +--rw name
| | string
| +---u ks:local-or-keystore-asymmetric-key-with-certs-grouping
+--rw end-entity-cert-with-key* [name]
+--rw name
| string
+---u ks:local-or-keystore-end-entity-cert-with-key-grouping
The following tree diagram illustrates the "ex-keystore-usage"
module, with all "grouping" statements expanded, enabling the usage's
full structure to be seen:
module: ex-keystore-usage
+--rw keystore-usage
+--rw symmetric-key* [name]
| +--rw name string
| +--rw (local-or-keystore)
| +--:(local) {local-definitions-supported}?
| | +--rw local-definition
| | +--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-value-format identityref
| | +--rw encrypted-value binary
| +--:(keystore) {central-keystore-supported}?
| +--rw keystore-reference? ks:symmetric-key-ref
+--rw asymmetric-key* [name]
| +--rw name string
| +--rw (local-or-keystore)
| +--:(local) {local-definitions-supported}?
| | +--rw local-definition
| | +--rw public-key-format identityref
| | +--rw public-key binary
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| | +--rw private-key-format? identityref
| | +--rw (private-key-type)
| | +--:(cleartext-private-key)
| | | +--rw cleartext-private-key? binary
| | +--:(hidden-private-key)
| | | +--rw hidden-private-key? empty
| | +--:(encrypted-private-key)
| | {private-key-encryption}?
| | +--rw encrypted-private-key
| | +--rw encrypted-by
| | +--rw encrypted-value-format identityref
| | +--rw encrypted-value binary
| +--:(keystore) {central-keystore-supported}?
| +--rw keystore-reference? ks:asymmetric-key-ref
+--rw asymmetric-key-with-certs* [name]
| +--rw name string
| +--rw (local-or-keystore)
| +--:(local) {local-definitions-supported}?
| | +--rw local-definition
| | +--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
| | | +--:(hidden-private-key)
| | | | +--rw hidden-private-key? empty
| | | +--:(encrypted-private-key)
| | | {private-key-encryption}?
| | | +--rw encrypted-private-key
| | | +--rw encrypted-by
| | | +--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
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| | +--ro certificate-signing-request ct:csr
| +--:(keystore) {central-keystore-supported}?
| +--rw keystore-reference? ks:asymmetric-key-ref
+--rw end-entity-cert-with-key* [name]
+--rw name string
+--rw (local-or-keystore)
+--:(local) {local-definitions-supported}?
| +--rw local-definition
| +--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
| | +--:(hidden-private-key)
| | | +--rw hidden-private-key? empty
| | +--:(encrypted-private-key)
| | {private-key-encryption}?
| | +--rw encrypted-private-key
| | +--rw encrypted-by
| | +--rw encrypted-value-format identityref
| | +--rw encrypted-value binary
| +--rw cert-data?
| | end-entity-cert-cms
| +---n certificate-expiration
| | {certificate-expiration-notification}?
| | +-- expiration-date yang:date-and-time
| +---x generate-certificate-signing-request
| {certificate-signing-request-generation}?
| +---w input
| | +---w csr-info ct:csr-info
| +--ro output
| +--ro certificate-signing-request ct:csr
+--:(keystore) {central-keystore-supported}?
+--rw keystore-reference
+--rw asymmetric-key? ks:asymmetric-key-ref
+--rw certificate? leafref
The following example provides two equivalent instances of each
grouping, the first being a reference to a keystore and the second
being locally-defined. The instance having a reference to a keystore
is consistent with the keystore defined in Section 2.2.1. The two
instances are equivalent, as the locally-defined instance example
contains the same values defined by the keystore instance referenced
by its sibling example.
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=============== NOTE: '\' line wrapping per RFC 8792 ================
<keystore-usage
xmlns="http://example.com/ns/example-keystore-usage"
xmlns:ct="urn:ietf:params:xml:ns:yang:ietf-crypto-types">
<!-- The following two equivalent examples illustrate the -->
<!-- "local-or-keystore-symmetric-key-grouping" grouping: -->
<symmetric-key>
<name>example 1a</name>
<keystore-reference>cleartext-symmetric-key</keystore-reference>
</symmetric-key>
<symmetric-key>
<name>example 1b</name>
<local-definition>
<key-format>ct:octet-string-key-format</key-format>
<cleartext-key>base64encodedvalue==</cleartext-key>
</local-definition>
</symmetric-key>
<!-- The following two equivalent examples illustrate the -->
<!-- "local-or-keystore-asymmetric-key-grouping" grouping: -->
<asymmetric-key>
<name>example 2a</name>
<keystore-reference>rsa-asymmetric-key</keystore-reference>
</asymmetric-key>
<asymmetric-key>
<name>example 2b</name>
<local-definition>
<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\
-key>
</local-definition>
</asymmetric-key>
<!-- the following two equivalent examples illustrate -->
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<!-- "local-or-keystore-asymmetric-key-with-certs-grouping": -->
<asymmetric-key-with-certs>
<name>example 3a</name>
<keystore-reference>rsa-asymmetric-key</keystore-reference>
</asymmetric-key-with-certs>
<asymmetric-key-with-certs>
<name>example 3b</name>
<local-definition>
<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\
-key>
<certificates>
<certificate>
<name>a locally-defined cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
</certificates>
</local-definition>
</asymmetric-key-with-certs>
<!-- The following two equivalent examples illustrate -->
<!-- "local-or-keystore-end-entity-cert-with-key-grouping": -->
<end-entity-cert-with-key>
<name>example 4a</name>
<keystore-reference>
<asymmetric-key>rsa-asymmetric-key</asymmetric-key>
<certificate>ex-rsa-cert</certificate>
</keystore-reference>
</end-entity-cert-with-key>
<end-entity-cert-with-key>
<name>example 4b</name>
<local-definition>
<public-key-format>
ct:subject-public-key-info-format
</public-key-format>
<public-key>base64encodedvalue==</public-key>
<private-key-format>
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ct:rsa-private-key-format
</private-key-format>
<cleartext-private-key>base64encodedvalue==</cleartext-private\
-key>
<cert-data>base64encodedvalue==</cert-data>
</local-definition>
</end-entity-cert-with-key>
</keystore-usage>
Following is the "ex-keystore-usage" module's YANG definition:
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 CCCC: A YANG Data Model for a Keystore";
}
organization
"Example Corporation";
contact
"Author: YANG Designer <mailto:yang.designer@example.com>";
description
"This module illustrates notable groupings defined in
the 'ietf-keystore' module.";
revision 2021-05-18 {
description
"Initial version";
reference
"RFC CCCC: A YANG Data Model for a Keystore";
}
container keystore-usage {
description
"An illustration of the various keystore groupings.";
list symmetric-key {
key "name";
leaf name {
type string;
description
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"An arbitrary name for this key.";
}
uses ks:local-or-keystore-symmetric-key-grouping;
description
"An symmetric key that may be configured locally or be a
reference to a symmetric key in the keystore.";
}
list asymmetric-key {
key "name";
leaf name {
type string;
description
"An arbitrary name for this key.";
}
uses ks:local-or-keystore-asymmetric-key-grouping;
description
"An asymmetric key, with no certs, that may be configured
locally or be a reference to an asymmetric key in the
keystore. The intent is to reference just the asymmetric
key, not any certificates that may also be associated
with the asymmetric key.";
}
list asymmetric-key-with-certs {
key "name";
leaf name {
type string;
description
"An arbitrary name for this key.";
}
uses ks: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 asymmetric
key, that may be configured locally or be a reference
to another certificate (and its associated asymmetric
key) in the keystore.";
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}
}
}
2.3. YANG Module
This YANG module has normative references to [RFC8341] and
[I-D.ietf-netconf-crypto-types].
<CODE BEGINS> file "ietf-keystore@2021-05-18.yang"
module ietf-keystore {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-keystore";
prefix ks;
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
import ietf-crypto-types {
prefix ct;
reference
"RFC AAAA: YANG Data Types and Groupings for Cryptography";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
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) 2021 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
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(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 2021-05-18 {
description
"Initial version";
reference
"RFC CCCC: A YANG Data Model for a Keystore";
}
/****************/
/* Features */
/****************/
feature central-keystore-supported {
description
"The 'central-keystore-supported' feature indicates that
the server supports the keystore.";
}
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, when this
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module is implemented.";
}
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, when this
module is implemented.";
}
/*****************/
/* Groupings */
/*****************/
grouping encrypted-by-choice-grouping {
description
"A grouping that defines a 'choice' statement that can be
augmented into the 'encrypted-by' node, present in the
'symmetric-key-grouping' and 'asymmetric-key-pair-grouping'
groupings defined in RFC AAAA, enabling references to keys
in the keystore, when this module is implemented.";
choice encrypted-by-choice {
nacm:default-deny-write;
mandatory true;
description
"A choice amongst other symmetric or asymmetric keys.";
case symmetric-key-ref {
leaf symmetric-key-ref {
type ks:symmetric-key-ref;
description
"Identifies the symmetric key used to encrypt the
associated key.";
}
}
case asymmetric-key-ref {
leaf asymmetric-key-ref {
type ks:asymmetric-key-ref;
description
"Identifies the asymmetric key whose public key
encrypted the associated key.";
}
}
}
}
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grouping asymmetric-key-certificate-ref-grouping {
description
"This grouping defines a reference to a specific certificate
associated with an asymmetric key stored in the keystore,
when this module is implemented.";
leaf asymmetric-key {
nacm:default-deny-write;
type ks:asymmetric-key-ref;
must '../certificate';
description
"A reference to an asymmetric key in the keystore.";
}
leaf certificate {
nacm:default-deny-write;
type leafref {
path "/ks:keystore/ks:asymmetric-keys/ks:asymmetric-key"
+ "[ks:name = current()/../asymmetric-key]/"
+ "ks:certificates/ks:certificate/ks:name";
}
must '../asymmetric-key';
description
"A reference to a specific certificate of the
asymmetric key in the keystore.";
}
}
// local-or-keystore-* groupings
grouping local-or-keystore-symmetric-key-grouping {
description
"A grouping that expands to allow the symmetric key to be
either stored locally, i.e., within the using data model,
or a reference to a symmetric key stored in the keystore.
Servers that do not 'implement' this module, and hence
'central-keystore-supported' is not defined, SHOULD
augment in custom 'case' statements enabling references
to the alternate keystore locations.";
choice local-or-keystore {
nacm:default-deny-write;
mandatory true;
description
"A choice between an inlined definition and a definition
that exists in the keystore.";
case local {
if-feature "local-definitions-supported";
container local-definition {
description
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"Container to hold the local key definition.";
uses ct:symmetric-key-grouping;
}
}
case keystore {
if-feature "central-keystore-supported";
leaf keystore-reference {
type ks:symmetric-key-ref;
description
"A reference to an symmetric key that exists in
the keystore, when this module is implemented.";
}
}
}
}
grouping local-or-keystore-asymmetric-key-grouping {
description
"A grouping that expands to allow the asymmetric key to be
either stored locally, i.e., within the using data model,
or a reference to an asymmetric key stored in the keystore.
Servers that do not 'implement' this module, and hence
'central-keystore-supported' is not defined, SHOULD
augment in custom 'case' statements enabling references
to the alternate keystore locations.";
choice local-or-keystore {
nacm:default-deny-write;
mandatory true;
description
"A choice between an inlined definition and a definition
that exists in the keystore.";
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"Container to hold the local key definition.";
uses ct:asymmetric-key-pair-grouping;
}
}
case keystore {
if-feature "central-keystore-supported";
leaf keystore-reference {
type ks:asymmetric-key-ref;
description
"A reference to an asymmetric key that exists in
the keystore, when this module is implemented. The
intent is to reference just the asymmetric key
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without any regard for any certificates that may
be associated with it.";
}
}
}
}
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,
i.e., within the using data model, or a reference to an
asymmetric key (and its associated certificates) stored
in the keystore.
Servers that do not 'implement' this module, and hence
'central-keystore-supported' is not defined, SHOULD
augment in custom 'case' statements enabling references
to the alternate keystore locations.";
choice local-or-keystore {
nacm:default-deny-write;
mandatory true;
description
"A choice between an inlined definition and a definition
that exists in the keystore.";
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"Container to hold the local key definition.";
uses ct:asymmetric-key-pair-with-certs-grouping;
}
}
case keystore {
if-feature "central-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, when
this module is implemented.";
}
}
}
}
grouping local-or-keystore-end-entity-cert-with-key-grouping {
description
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"A grouping that expands to allow an end-entity certificate
(and its associated asymmetric key pair) to be either stored
locally, i.e., within the using data model, or a reference
to a specific certificate in the keystore.
Servers that do not 'implement' this module, and hence
'central-keystore-supported' is not defined, SHOULD
augment in custom 'case' statements enabling references
to the alternate keystore locations.";
choice local-or-keystore {
nacm:default-deny-write;
mandatory true;
description
"A choice between an inlined definition and a definition
that exists in the keystore.";
case local {
if-feature "local-definitions-supported";
container local-definition {
description
"Container to hold the local key definition.";
uses ct:asymmetric-key-pair-with-cert-grouping;
}
}
case keystore {
if-feature "central-keystore-supported";
container keystore-reference {
uses asymmetric-key-certificate-ref-grouping;
description
"A reference to a specific certificate associated with
an asymmetric key stored in the keystore, when this
module is implemented.";
}
}
}
}
grouping keystore-grouping {
description
"Grouping definition enables use in other contexts. If ever
done, implementations MUST augment new 'case' statements
into the various local-or-keystore 'choice' statements to
supply leafrefs to the model-specific location(s).";
container asymmetric-keys {
nacm:default-deny-write;
description
"A list of asymmetric keys.";
list asymmetric-key {
key "name";
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description
"An asymmetric key.";
leaf name {
type string;
description
"An arbitrary name for the asymmetric key.";
}
uses ct:asymmetric-key-pair-with-certs-grouping;
}
}
container symmetric-keys {
nacm:default-deny-write;
description
"A list of symmetric keys.";
list symmetric-key {
key "name";
description
"A symmetric key.";
leaf name {
type string;
description
"An arbitrary name for the symmetric key.";
}
uses ct:symmetric-key-grouping;
}
}
}
/*********************************/
/* Protocol accessible nodes */
/*********************************/
container keystore {
description
"A central keystore containing a list of symmetric keys and
a list of asymmetric keys.";
nacm:default-deny-write;
uses keystore-grouping {
augment "symmetric-keys/symmetric-key/key-type/encrypted-key/"
+ "encrypted-key/encrypted-by" {
description
"Augments in a choice statement enabling the encrypting
key to be any other symmetric or asymmetric key in the
central keystore.";
uses encrypted-by-choice-grouping;
}
augment "asymmetric-keys/asymmetric-key/private-key-type/"
+ "encrypted-private-key/encrypted-private-key/"
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+ "encrypted-by" {
description
"Augments in a choice statement enabling the encrypting
key to be any other symmetric or asymmetric key in the
central keystore.";
uses encrypted-by-choice-grouping;
}
}
}
}
<CODE ENDS>
3. Support for Built-in Keys
In some implementations, a server may support built-in keys. 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 primary 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
keystore in <operational> might look like for a server in its factory
default state.
<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-key-format>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/>
<certificates>
<certificate>
<name>Manufacturer-Generated IDevID Cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
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In order for the built-in keys (and their associated built-in
certificates) to be referenced by configuration, the referenced keys
and associated certificates MUST first be copied into <running>.
Built-in keys that are "hidden" MUST be copied into <running> using
the same key values, so that the server can bind them to the built-in
entries.
Built-in keys that are "encrypted" MAY be copied into other parts of
the configuration so long as they are otherwise unmodified (e.g., the
"encrypted-by" reference cannot be altered).
Built-in keys that are "cleartext" MAY be copied into other parts of
the configuration but, by doing so, they lose their association to
the built-in entries and any assurances afforded by knowing they are/
were built-in.
The built-in keys and built-in associated certificates are immutable
by configuration operations. With exception to additional/custom
certificates associated to a built-in key, servers MUST ignore
attempts to modify any aspect of built-in keys and/or built-in
associated certificates.
The following example illustrates how a single built-in key
definition from the previous example has been propagated to
<running>:
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<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-key-format>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/>
<certificates>
<certificate>
<name>Manufacturer-Generated IDevID Cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
<certificate>
<name>Deployment-Specific LDevID Cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
After the above configuration is applied, <operational> should appear
as follows:
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<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-key-format>
<public-key>base64encodedvalue==</public-key>
<hidden-private-key/>
<certificates>
<certificate>
<name>Manufacturer-Generated IDevID Cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
<certificate or:origin="or:intended">
<name>Deployment-Specific LDevID Cert</name>
<cert-data>base64encodedvalue==</cert-data>
</certificate>
</certificates>
</asymmetric-key>
</asymmetric-keys>
</keystore>
4. Encrypting Keys in Configuration
This section describes an approach that enables both the symmetric
and asymmetric keys on a server to be encrypted, such that
traditional backup/restore procedures can be used without concern for
the keys being compromised when in transit.
4.1. Key Encryption Key
The ability to encrypt configured keys is predicated on the existence
of a "key encryption key" (KEK). There may be any number of KEKs in
a system. A KEK, by its namesake, is a key that is used to encrypt
other keys. A KEK MAY be either a symmetric key or an asymmetric
key.
If a KEK is a symmetric key, then the server MUST provide an API for
administrators to encrypt other keys without needing to know the
symmetric key's value. If the KEK is an asymmetric key, then the
server MAY provide an API enabling the encryption of other keys or,
alternatively, let the administrators do so themselves using the
asymmetric key's public half.
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A server MUST possess (or be able to possess, in case the KEK has
been encrypted by another KEK) a KEK's cleartext value so that it can
decrypt the other keys in the configuration at runtime.
4.2. Configuring Encrypted Keys
Each time a new key is configured, it SHOULD be encrypted by a KEK.
In "ietf-crypto-types" [I-D.ietf-netconf-crypto-types], the format
for encrypted values is described by identity statements derived from
the "symmetrically-encrypted-value-format" and "symmetrically-
encrypted-value-format" identity statements.
Implementations SHOULD provide an API that simultaneously generates
and encrypts a key (symmetric or asymmetric) using a KEK. Thusly
newly generated key cleartext values may never known to the
administrators generating the 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
(e.g., an organization's crypto officer).
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 KEK
that encrypted the key.
4.3. Migrating Configuration to Another Server
When a KEK is used to encrypt other keys, migrating the configuration
to another server is only possible if the second server has the same
KEK. How the second server comes to have the same KEK is discussed
in this section.
In some deployments, mechanisms outside the scope of this document
may be used to migrate a KEK from one server to another. That said,
beware that the ability to do so typically entails having access to
the first server but, in many scenarios, the first server may no
longer be operational.
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In other deployments, an organization's crypto officer, possessing a
KEK's cleartext value, configures the same KEK on the second server,
presumably as a hidden key or a key protected by access-control
(e.g., NACM's "default-deny-all"), so that the cleartext value is not
disclosed to regular administrators. However, this approach creates
high-coupling to and dependency on the crypto officers that doesn't
scale in production environments.
In order to decouple the crypto officers from the regular
administrators, a special KEK, called the "master key" (MK), may be
used.
A MK is commonly a globally-unique built-in (see Section 3)
asymmetric key. The private key, due to its long lifetime, is hidden
(i.e., "hidden-private-key" in Section 2.1.4.5. of
[I-D.ietf-netconf-crypto-types]). The public key is often contained
in an identity certificate (e.g., IDevID). How to configure a MK
during the manufacturing process is outside the scope of this
document.
It is RECOMMENDED that MKs are built-in and hidden but, if this is
not possible, access control mechanisms like NACM SHOULD be used to
limit access to the MK's secret data only to the most trusted
authorized clients (e.g., an organization's crypto officer). In this
case, it is RECOMMENDED that the MK is not built-in and hence is,
effectively, just like a KEK.
Assuming the server has a MK, the MK can be used to encrypt a "shared
KEK", which is then used to encrypt the keys configured by regular
administrators.
With this extra level of indirection, it is possible for a crypto
officer to encrypt the same KEK for a multiplicity of servers offline
using the public key contained in their identity certificates. The
crypto officer can then safely handoff the encrypted KEKs to the
regular administrators responsible for server installations,
including migrations.
In order to migrate the configuration from a first server, an
administrator would need to make just a single modification to the
configuration before loading it onto a second server, which is to
replace the encrypted KEK keystore entry from the first server with
the encrypted KEK for the second server. Upon doing this, the
configuration (containing many encrypted keys) can be loaded into the
second server while enabling the second server to decrypt all the
encrypted keys in the configuration.
The following diagram illustrates this idea:
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+-------------+ +-------------+
| shared KEK | | shared KEK |
|(unencrypted)|-------------------------------> | (encrypted) |
+-------------+ encrypts offline using +-------------+
^ each server's MK |
| |
| |
| possesses \o |
+-------------- |\ |
/ \ shares with |
crypto +--------------------+
officer |
|
|
+----------------------+ | +----------------------+
| server-1 | | | server-2 |
| configuration | | | configuration |
| | | | |
| | | | |
| +----------------+ | | | +----------------+ |
| | MK-1 | | | | | MK-2 | |
| | (hidden) | | | | | (hidden) | |
| +----------------+ | | | +----------------+ |
| ^ | | | ^ |
| | | | | | |
| | | | | | |
| | encrypted | | | | encrypted |
| | by | | | | by |
| | | | | | |
| | | | | | |
| +----------------+ | | | +----------------+ |
| | shared KEK | | | | | shared KEK | |
| | (encrypted) | | v | | (encrypted) | |
| +----------------+ | | +----------------+ |
| ^ | regular | ^ |
| | | admin | | |
| | | | | |
| | encrypted | \o | | encrypted |
| | by | |\ | | by |
| | | / \ | | |
| | | | | |
| +----------------+ |----------------->| +----------------+ |
| | all other keys | | migrate | | all other keys | |
| | (encrypted) | | configuration | | (encrypted) | |
| +----------------+ | | +----------------+ |
| | | |
+----------------------+ +----------------------+
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5. Security Considerations
5.1. Security of Data at Rest
The YANG module defined in this document defines a mechanism called a
"keystore" that, by its name, suggests that it will protect its
contents from unauthorized disclosure and modification.
Security controls for the API (i.e., data in motion) are discussed in
Section 5.3, but controls for the data at rest cannot be specified by
the YANG module.
In order to satisfy the expectations of a "keystore", it is
RECOMMENDED that implementations ensure that the keystore contents
are encrypted when persisted to non-volatile memory.
5.2. Unconstrained Private Key Usage
This module enables the configuration of private keys without
constraints on their usage, e.g., what operations the key is allowed
to be used for (e.g., signature, decryption, both).
This module also does not constrain the usage of the associated
public keys, other than in the context of a configured certificate
(e.g., an identity certificate), in which case the key usage is
constrained by the certificate.
5.3. The "ietf-keystore" YANG Module
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.
None of the readable data nodes defined in this YANG module are
considered sensitive or vulnerable in network environments. The NACM
"default-deny-all" extension has not been set for any data nodes
defined in this module.
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| Please be aware that this module uses the "cleartext-key" and
| "cleartext-private-key" nodes from the "ietf-crypto-types"
| module [I-D.ietf-netconf-crypto-types], where said nodes have
| the NACM extension "default-deny-all" set, thus preventing
| uncontrolled read-access to the cleartext key values.
All of the writable data nodes defined by this module, both in the
"grouping" statements as well as the protocol-accessible "keystore"
instance, may be considered sensitive or vulnerable in some network
environments.. For instance, any modification to a key or reference
to a key may dramatically alter the implemented security policy. For
this reason, the NACM extension "default-deny-write" has been set for
all data nodes defined in this module.
This module does not define any "rpc" or "action" statements, and
thus the security considerations for such is not provided here.
6. IANA Considerations
6.1. The "IETF XML" Registry
This document registers one URI in the "ns" subregistry of the IETF
XML Registry [RFC3688]. Following the format in [RFC3688], the
following registration is requested:
URI: urn:ietf:params:xml:ns:yang:ietf-keystore
Registrant Contact: The IESG
XML: N/A, the requested URI is an XML namespace.
6.2. The "YANG Module Names" Registry
This document registers one YANG module in the YANG Module Names
registry [RFC6020]. Following the format in [RFC6020], the following
registration is requested:
name: ietf-keystore
namespace: urn:ietf:params:xml:ns:yang:ietf-keystore
prefix: ks
reference: RFC CCCC
7. References
7.1. Normative References
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[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-19, 10 February 2021,
<https://tools.ietf.org/html/draft-ietf-netconf-crypto-
types-19>.
[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>.
7.2. Informative References
[I-D.ietf-netconf-http-client-server]
Watsen, K., "YANG Groupings for HTTP Clients and HTTP
Servers", Work in Progress, Internet-Draft, draft-ietf-
netconf-http-client-server-06, 10 February 2021,
<https://tools.ietf.org/html/draft-ietf-netconf-http-
client-server-06>.
[I-D.ietf-netconf-keystore]
Watsen, K., "A YANG Data Model for a Keystore", Work in
Progress, Internet-Draft, draft-ietf-netconf-keystore-21,
10 February 2021, <https://tools.ietf.org/html/draft-ietf-
netconf-keystore-21>.
[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-22, 10 February 2021,
<https://tools.ietf.org/html/draft-ietf-netconf-netconf-
client-server-22>.
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[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-22, 10 February 2021,
<https://tools.ietf.org/html/draft-ietf-netconf-restconf-
client-server-22>.
[I-D.ietf-netconf-ssh-client-server]
Watsen, K., "YANG Groupings for SSH Clients and SSH
Servers", Work in Progress, Internet-Draft, draft-ietf-
netconf-ssh-client-server-23, 10 February 2021,
<https://tools.ietf.org/html/draft-ietf-netconf-ssh-
client-server-23>.
[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-09, 10 February 2021,
<https://tools.ietf.org/html/draft-ietf-netconf-tcp-
client-server-09>.
[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-23, 10 February 2021,
<https://tools.ietf.org/html/draft-ietf-netconf-tls-
client-server-23>.
[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-14, 10 February 2021,
<https://tools.ietf.org/html/draft-ietf-netconf-trust-
anchors-14>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
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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>.
[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>.
Appendix A. Change Log
This section is to be removed before publishing as an RFC.
A.1. 00 to 01
* Replaced the 'certificate-chain' structures with PKCS#7
structures. (Issue #1)
* Added 'private-key' as a configurable data node, and removed the
'generate-private-key' and 'load-private-key' actions. (Issue #2)
* Moved 'user-auth-credentials' to the ietf-ssh-client module.
(Issues #4 and #5)
A.2. 01 to 02
* Added back 'generate-private-key' action.
* Removed 'RESTRICTED' enum from the 'private-key' leaf type.
* Fixed up a few description statements.
A.3. 02 to 03
* Changed draft's title.
* Added missing references.
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* Collapsed sections and levels.
* Added RFC 8174 to Requirements Language Section.
* Renamed 'trusted-certificates' to 'pinned-certificates'.
* Changed 'public-key' from config false to config true.
* Switched 'host-key' from OneAsymmetricKey to definition from RFC
4253.
A.4. 03 to 04
* Added typedefs around leafrefs to common keystore paths
* Now tree diagrams reference ietf-netmod-yang-tree-diagrams
* Removed Design Considerations section
* Moved key and certificate definitions from data tree to groupings
A.5. 04 to 05
* Removed trust anchors (now in their own draft)
* Added back global keystore structure
* Added groupings enabling keys to either be locally defined or a
reference to the keystore.
A.6. 05 to 06
* Added feature "local-keys-supported"
* Added nacm:default-deny-all and nacm:default-deny-write
* Renamed generate-asymmetric-key to generate-hidden-key
* Added an install-hidden-key action
* Moved actions inside fo the "asymmetric-key" container
* Moved some groupings to draft-ietf-netconf-crypto-types
A.7. 06 to 07
* Removed a "require-instance false"
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* Clarified some description statements
* Improved the keystore-usage examples
A.8. 07 to 08
* Added "local-definition" containers to avoid posibility of the
action/notification statements being under a "case" statement.
* Updated copyright date, boilerplate template, affiliation, folding
algorithm, and reformatted the YANG module.
A.9. 08 to 09
* Added a 'description' statement to the 'must' in the /keystore/
asymmetric-key node explaining that the descendent values may
exist in <operational> only, and that implementation MUST assert
that the values are either configured or that they exist in
<operational>.
* Copied above 'must' statement (and description) into the 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
* Updated draft title to match new truststore draft title
* Moved everything under a top-level 'grouping' to enable use in
other contexts.
* Renamed feature from 'local-keys-supported' to 'local-definitions-
supported' (same name used in truststore)
* Removed the either-all-or-none 'must' expressions for the key's
3-tuple values (since the values are now 'mandatory true' in
crypto-types)
* Example updated to reflect 'mandatory true' change in crypto-types
draft
A.11. 10 to 11
* Replaced typedef asymmetric-key-certificate-ref with grouping
asymmetric-key-certificate-ref-grouping.
* Added feature feature 'key-generation'.
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* Cloned groupings symmetric-key-grouping, asymmetric-key-pair-
grouping, asymmetric-key-pair-with-cert-grouping, and asymmetric-
key-pair-with-certs-grouping from crypto-keys, augmenting into
each new case statements for values that have been encrypted by
other keys in the keystore. Refactored keystore model to use
these groupings.
* Added new 'symmetric-keys' lists, as a sibling to the existing
'asymmetric-keys' list.
* Added RPCs (not actions) 'generate-symmetric-key' and 'generate-
asymmetric-key' to *return* a (potentially encrypted) key.
A.12. 11 to 12
* Updated to reflect crypto-type's draft using enumerations over
identities.
* Added examples for the 'generate-symmetric-key' and 'generate-
asymmetric-key' RPCs.
* Updated the Introduction section.
A.13. 12 to 13
* Updated examples to incorporate new "key-format" identities.
* Made the two "generate-*-key" RPCs be "action" statements instead.
A.14. 13 to 14
* Updated YANG module and examples to incorporate the new
iana-*-algorithm modules in the crypto-types draft..
A.15. 14 to 15
* Added new "Support for Built-in Keys" section.
* Added 'must' expressions asserting that the 'key-format' leaf
whenever an encrypted key is specified.
* Added local-or-keystore-symmetric-key-grouping for PSK support.
A.16. 15 to 16
* Moved the generate key actions to ietf-crypt-types as RPCs, which
are augmented by ietf-keystore to support encrypted keys.
Examples updated accordingly.
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* Added a SSH certificate-based key (RFC 6187) and a raw private key
to the example instance document (partly so they could be
referenced by examples in the SSH and TLS client/server drafts.
A.17. 16 to 17
* Removed augments to the "generate-symmetric-key" and "generate-
asymmetric-key" groupings.
* Removed "generate-symmetric-key" and "generate-asymmetric-key"
examples.
* Removed the "algorithm" nodes from remaining examples.
* Updated the "Support for Built-in Keys" section.
* Added new section "Encrypting Keys in Configuration".
* Added a "Note to Reviewers" note to first page.
A.18. 17 to 18
* Removed dangling/unnecessary ref to RFC 8342.
* r/MUST/SHOULD/ wrt strength of keys being configured over
transports.
* Added an example for the "certificate-expiration" notification.
* Clarified that OS MAY have a multiplicity of underlying keystores
and/or HSMs.
* Clarified expected behavior for "built-in" keys in <operational>
* Clarified the "Migrating Configuration to Another Server" section.
* Expanded "Data Model Overview section(s) [remove "wall" of tree
diagrams].
* Updated the Security Considerations section.
A.19. 18 to 19
* Updated examples to reflect new "cleartext-" prefix in the crypto-
types draft.
A.20. 19 to 20
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* Addressed SecDir comments from Magnus Nystroem and Sandra Murphy.
A.21. 20 to 21
* Added a "Unconstrained Private Key Usage" Security Consideration
to address concern raised by SecDir.
* (Editorial) Removed the output of "grouping" statements in the
tree diagrams for the "ietf-keystore" and "ex-keystore-usage"
modules.
* Addressed comments raised by YANG Doctor.
A.22. 21 to 22
* Added prefixes to 'path' statements per trust-anchors/issues/1
* Renamed feature "keystore-supported" to "central-keystore-
supported".
* Associated with above, generally moved text to refer to a
"central" keystore.
* Aligned modules with `pyang -f` formatting.
* Fixed nits found by YANG Doctor reviews.
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, Magnus Nystroem, Martin Bjoerklund, Mehmet Ersue, Phil
Shafer, Radek Krejci, Ramkumar Dhanapal, Reshad Rahman, Sandra
Murphy, Sean Turner, and Tom Petch.
Author's Address
Kent Watsen
Watsen Networks
Email: kent+ietf@watsen.net
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