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