Using HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512 with IPsec
RFC 4868
| Document | Type |
RFC - Proposed Standard
(May 2007; Errata)
Was draft-kelly-ipsec-ciph-sha2 (individual in sec area)
|
|
|---|---|---|---|
| Last updated | 2020-01-21 | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized with errata bibtex | ||
| Reviews | |||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 4868 (Proposed Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Russ Housley | ||
| Send notices to | (None) | ||
Network Working Group S. Kelly
Request for Comments: 4868 Aruba Networks
Category: Standards Track S. Frankel
NIST
May 2007
Using HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512 with IPsec
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
This specification describes the use of Hashed Message Authentication
Mode (HMAC) in conjunction with the SHA-256, SHA-384, and SHA-512
algorithms in IPsec. These algorithms may be used as the basis for
data origin authentication and integrity verification mechanisms for
the Authentication Header (AH), Encapsulating Security Payload (ESP),
Internet Key Exchange Protocol (IKE), and IKEv2 protocols, and also
as Pseudo-Random Functions (PRFs) for IKE and IKEv2. Truncated
output lengths are specified for the authentication-related variants,
with the corresponding algorithms designated as HMAC-SHA-256-128,
HMAC-SHA-384-192, and HMAC-SHA-512-256. The PRF variants are not
truncated, and are called PRF-HMAC-SHA-256, PRF-HMAC-SHA-384, and
PRF-HMAC-SHA-512.
Kelly & Frankel Standards Track [Page 1]
RFC 4868 HMAC-SHA256, SHA384, and SHA512 in IPsec May 2007
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. The HMAC-SHA-256+ Algorithms . . . . . . . . . . . . . . . . . 3
2.1. Keying Material . . . . . . . . . . . . . . . . . . . . . 3
2.1.1. Data Origin Authentication and Integrity
Verification Usage . . . . . . . . . . . . . . . . . . 4
2.1.2. Pseudo-Random Function (PRF) Usage . . . . . . . . . . 4
2.1.3. Randomness and Key Strength . . . . . . . . . . . . . 5
2.1.4. Key Distribution . . . . . . . . . . . . . . . . . . . 5
2.1.5. Refreshing Keys . . . . . . . . . . . . . . . . . . . 5
2.2. Padding . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3. Truncation . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4. Using HMAC-SHA-256+ as PRFs in IKE and IKEv2 . . . . . . . 7
2.5. Interactions with the ESP, IKE, or IKEv2 Cipher
Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . 7
2.6. HMAC-SHA-256+ Parameter Summary . . . . . . . . . . . . . 7
2.7. Test Vectors . . . . . . . . . . . . . . . . . . . . . . . 7
2.7.1. PRF Test Vectors . . . . . . . . . . . . . . . . . . . 8
2.7.2. Authenticator Test Vectors . . . . . . . . . . . . . . 11
3. Security Considerations . . . . . . . . . . . . . . . . . . . 17
3.1. HMAC Key Length vs Truncation Length . . . . . . . . . . . 17
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1. Normative References . . . . . . . . . . . . . . . . . . . 19
6.2. Informative References . . . . . . . . . . . . . . . . . . 20
Kelly & Frankel Standards Track [Page 2]
RFC 4868 HMAC-SHA256, SHA384, and SHA512 in IPsec May 2007
1. Introduction
This document specifies the use of SHA-256, SHA-384, and SHA-512
[SHA2-1] combined with HMAC [HMAC] as data origin authentication and
integrity verification mechanisms for the IPsec AH [AH], ESP [ESP],
IKE [IKE], and IKEv2 [IKEv2] protocol. Output truncation is
specified for these variants, with the corresponding algorithms
designated as HMAC-SHA-256-128, HMAC-SHA-384-192, and HMAC-SHA-512-
256. These truncation lengths are chosen in accordance with the
birthday bound for each algorithm.
This specification also describes untruncated variants of these
algorithms as Pseudo-Random Functions (PRFs) for use with IKE and
IKEv2, and those algorithms are called PRF-HMAC-SHA-256, PRF-HMAC-
SHA-384, and PRF-HMAC-SHA-512. For ease of reference, these PRF
algorithms and the authentication variants described above are
collectively referred to below as "the HMAC-SHA-256+ algorithms".
The goal of the PRF variants are to provide secure pseudo-random
functions suitable for generation of keying material and other
protocol-specific numeric quantities, while the goal of the
authentication variants is to ensure that packets are authentic and
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