Additional Methods for Generating Key Identifiers Values
RFC 7093
| Document | Type |
RFC - Informational
(December 2013; No errata)
Was draft-turner-additional-methods-4kis (individual)
|
|
|---|---|---|---|
| Last updated | 2013-12-20 | ||
| Stream | ISE | ||
| Formats | plain text pdf html bibtex | ||
| IETF conflict review | conflict-review-turner-additional-methods-4kis | ||
| Stream | ISE state | Published RFC | |
| Consensus Boilerplate | Unknown | ||
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 7093 (Informational) | |
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
| IANA | IANA review state | IANA OK - No Actions Needed | |
| IANA action state | No IANA Actions | ||
Independent Submission S. Turner
Request for Comments: 7093 IECA
Category: Informational S. Kent
ISSN: 2070-1721 BBN
J. Manger
Telstra
December 2013
Additional Methods for Generating Key Identifiers Values
Abstract
This document specifies additional example methods for generating Key
Identifier values for use in the AKI (Authority Key Identifier) and
SKI (Subject Key Identifier) certificate extensions.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7093.
Copyright Notice
Copyright (c) 2013 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
(http://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.
Turner, et al. Informational [Page 1]
RFC 7093 Additional Examples For KIs December 2013
1. Introduction
[RFC5280] defines the AKI (Authority Key Identifier) and SKI (Subject
Key Identifier) certificate extensions. [RFC5280] describes two
example mechanisms for generating AKI and SKI values: a 160-bit SHA-1
(Secure Hash Algorithm) hash of the public key and a four-bit type
field with the value 0100 followed by the least significant 60 bits
of the SHA-1 hash. Both of these mechanisms were designed to not be
critical to security. This document defines three additional
mechanisms for generating Key Identifier values using SHA-256,
SHA-384, and SHA-512 [SHS] that are similar to those examples defined
in [RFC5280] as well as one based on hashing the certificate's
Subject Public Key Info field.
2. Additional Methods for Generating Key Identifiers
[RFC5280] specifies two examples for generating key identifiers from
public keys. Four additional mechanisms are as follows:
1) The keyIdentifier is composed of the leftmost 160-bits of the
SHA-256 hash of the value of the BIT STRING subjectPublicKey
(excluding the tag, length, and number of unused bits).
2) The keyIdentifier is composed of the leftmost 160-bits of the
SHA-384 hash of the value of the BIT STRING subjectPublicKey
(excluding the tag, length, and number of unused bits).
3) The keyIdentifier is composed of the leftmost 160-bits of the
SHA-512 hash of the value of the BIT STRING subjectPublicKey
(excluding the tag, length, and number of unused bits).
4) The keyIdentifier is composed of the hash of the DER encoding of
the SubjectPublicKeyInfo value.
Turner, et al. Informational [Page 2]
RFC 7093 Additional Examples For KIs December 2013
3. Examples
This section provides some examples. The keys and SKIs are presented
in hexadecimal (two hex digits per byte).
Given the following DER-encoded SubjectPublicKeyInfo value holding an
P-256 ECDSA (Elliptic Curve Digital Signature Algorithm) key:
30 59
30 13
06 07 2A8648CE3D0201 -- id-ecPublicKey
06 08 2A8648CE3D030107 -- secp256r1
03 42 00
04 7F7F35A79794C950060B8029FC8F363A
28F11159692D9D34E6AC948190434735
F833B1A66652DC514337AFF7F5C9C75D
670C019D95A5D639B72744C64A9128BB
The SHA-256 hash of the 65 bytes 047F7F...BB is:
BF37B3E5808FD46D54B28E846311BCCE1CAD2E1A62AA9092EF3EFB3F11451F44
The SHA-1 hash of these 65 bytes is:
6FEF9162C0A3F2E7608956D41C37DA0C8E87F0AE
The SHA-256 hash of the 91 bytes 305930...BB is:
6D20896AB8BD833B6B66554BD59B20225D8A75A296088148399D7BF763D57405
Using method 1 from Section 2, the subjectKeyIdentifier would be:
30 1D
06 03 551D0E -- id-ce-subjectKeyIdentifier
04 16
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