RFC 2404 (rfc2404) - Page 1 of 7


The Use of HMAC-SHA-1-96 within ESP and AH



Alternative Format: Original Text Document



Network Working Group                                          C. Madson
Request for Comments: 2404                            Cisco Systems Inc.
Category: Standards Track                                       R. Glenn
                                                                    NIST
                                                           November 1998


               The Use of HMAC-SHA-1-96 within ESP and AH

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 Internet Society (1998).  All Rights Reserved.

Abstract

   This memo describes the use of the HMAC algorithm [RFC-2104] in
   conjunction with the SHA-1 algorithm [FIPS-180-1] as an
   authentication mechanism within the revised IPSEC Encapsulating
   Security Payload [ESP] and the revised IPSEC Authentication Header
   [AH]. HMAC with SHA-1 provides data origin authentication and
   integrity protection.

   Further information on the other components necessary for ESP and AH
   implementations is provided by [Thayer97a].

1.  Introduction

   This memo specifies the use of SHA-1 [FIPS-180-1] combined with HMAC
   [RFC-2104] as a keyed authentication mechanism within the context of
   the Encapsulating Security Payload and the Authentication Header.
   The goal of HMAC-SHA-1-96 is to ensure that the packet is authentic
   and cannot be modified in transit.

   HMAC is a secret key authentication algorithm. Data integrity and
   data origin authentication as provided by HMAC are dependent upon the
   scope of the distribution of the secret key. If only the source and
   destination know the HMAC key, this provides both data origin






Madson & Glenn              Standards Track