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Wrapping a Hashed Message Authentication Code (HMAC) key with a Triple-Data Encryption Standard (DES) Key or an Advanced Encryption Standard (AES) Key (RFC3537)

IP.com Disclosure Number: IPCOM000012811D
Original Publication Date: 2003-May-01
Included in the Prior Art Database: 2003-May-30
Document File: 10 page(s) / 17K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Schaad: AUTHOR [+2]

Abstract

This document defines two methods for wrapping an HMAC (Hashed Message Authentication Code) key. The first method defined uses a Triple DES (Data Encryption Standard) key to encrypt the HMAC key. The second method defined uses an AES (Advanced Encryption Standard) key to encrypt the HMAC key. One place that such an algorithm is used is for the Authenticated Data type in CMS (Cryptographic Message Syntax).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 16% of the total text.

Network Working Group                                          J. Schaad

Request for Comments: 3537                       Soaring Hawk Consulting

Category: Standards Track                                     R. Housley

                                                          Vigil Security

                                                                May 2003

       Wrapping a Hashed Message Authentication Code (HMAC) key

           with a Triple-Data Encryption Standard (DES) Key

             or an Advanced Encryption Standard (AES) Key

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 defines two methods for wrapping an HMAC (Hashed

   Message Authentication Code) key.  The first method defined uses a

   Triple DES (Data Encryption Standard) key to encrypt the HMAC key.

   The second method defined uses an AES (Advanced Encryption Standard)

   key to encrypt the HMAC key.  One place that such an algorithm is

   used is for the Authenticated Data type in CMS (Cryptographic Message

   Syntax).

1. Introduction

   Standard methods exist for encrypting a Triple-DES (3DES) content-

   encryption key (CEK) with a 3DES key-encryption key (KEK) [3DES-

   WRAP], and for encrypting an AES CEK with an AES KEK [AES-WRAP].

   Triple-DES key wrap imposes parity restrictions, and in both

   instances there are restrictions on the size of the key being wrapped

   that make the encryption of HMAC [HMAC] keying material difficult.

   This document specifies a mechanism for the encryption of an HMAC key

   of arbitrary length by a 3DES KEK or an AES KEK.

Schaad & Housley            Standards Track                     [Page 1]

RFC 3537                     HMAC Key Wrap                      May 2003

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",

   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this

   document are to be interpreted as described in BCP 14, RFC 2119

   [STDWORDS].

2. HMAC Key Guidelines

   [HMAC] suggests that the key be at least as long as the output (L) of

   the hash function being used.  When keys longer than the block size

   of the hash algorithm are used, they are hashed and the resulting

   hash value is used.  Using keys much longer than L...