RFC 2402 (rfc2402) - Page 1 of 22


IP Authentication Header



Alternative Format: Original Text Document



Network Working Group                                            S. Kent
Request for Comments: 2402                                      BBN Corp
Obsoletes: 1826                                              R. Atkinson
Category: Standards Track                                  @Home Network
                                                           November 1998


                        IP Authentication Header

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.

Table of Contents

  1. Introduction......................................................2
  2. Authentication Header Format......................................3
     2.1 Next Header...................................................4
     2.2 Payload Length................................................4
     2.3 Reserved......................................................4
     2.4 Security Parameters Index (SPI)...............................4
     2.5 Sequence Number...............................................5
     2.6 Authentication Data ..........................................5
  3. Authentication Header Processing..................................5
     3.1  Authentication Header Location...............................5
     3.2  Authentication Algorithms....................................7
     3.3  Outbound Packet Processing...................................8
        3.3.1  Security Association Lookup.............................8
        3.3.2  Sequence Number Generation..............................8
        3.3.3  Integrity Check Value Calculation.......................9
           3.3.3.1  Handling Mutable Fields............................9
              3.3.3.1.1  ICV Computation for IPv4.....................10
                 3.3.3.1.1.1 Base Header Fields.......................10
                 3.3.3.1.1.2 Options..................................11
              3.3.3.1.2  ICV Computation for IPv6.....................11
                 3.3.3.1.2.1 Base Header Fields.......................11
                 3.3.3.1.2.2 Extension Headers Containing Options.....11
                 3.3.3.1.2.3 Extension Headers Not Containing Options.11
           3.3.3.2  Padding...........................................12
              3.3.3.2.1  Authentication Data Padding..................12



Kent & Atkinson             Standards Track