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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).

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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...