RFC 3602 (rfc3602) - Page 1 of 15


The AES-CBC Cipher Algorithm and Its Use with IPsec



Alternative Format: Original Text Document



Network Working Group                                         S. Frankel
Request for Comments: 3602                                      R. Glenn
Category: Standards Track                                           NIST
                                                                S. Kelly
                                                               Airespace
                                                          September 2003


          The AES-CBC Cipher Algorithm and Its Use 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 Internet Society (2003).  All Rights Reserved.

Abstract

   This document describes the use of the Advanced Encryption Standard
   (AES) Cipher Algorithm in Cipher Block Chaining (CBC) Mode, with an
   explicit Initialization Vector (IV), as a confidentiality mechanism
   within the context of the IPsec Encapsulating Security Payload (ESP).

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
       1.1.  Specification of Requirements. . . . . . . . . . . . . .  3
   2.  The AES Cipher Algorithm . . . . . . . . . . . . . . . . . . .  3
       2.1.  Mode . . . . . . . . . . . . . . . . . . . . . . . . . .  3
       2.2.  Key Size and Number of Rounds. . . . . . . . . . . . . .  4
       2.3.  Weak Keys. . . . . . . . . . . . . . . . . . . . . . . .  4
       2.4.  Block Size and Padding . . . . . . . . . . . . . . . . .  4
       2.5.  Additional Information . . . . . . . . . . . . . . . . .  4
       2.6.  Performance. . . . . . . . . . . . . . . . . . . . . . .  5
   3.  ESP Payload  . . . . . . . . . . . . . . . . . . . . . . . . .  5
       3.1.  ESP Algorithmic Interactions . . . . . . . . . . . . . .  6
       3.2.  Keying Material. . . . . . . . . . . . . . . . . . . . .  6
   4.  Test Vectors . . . . . . . . . . . . . . . . . . . . . . . . .  6
   5.  IKE Interactions . . . . . . . . . . . . . . . . . . . . . . . 10
       5.1.  Phase 1 Identifier . . . . . . . . . . . . . . . . . . . 10
       5.2.  Phase 2 Identifier . . . . . . . . . . . . . . . . . . . 10
       5.3.  Key Length Attribute . . . . . . . . . . . . . . . . . . 10



Frankel, et al.             Standards Track