draft-ietf-bfd-hmac-sha-03.txt   draft-ietf-bfd-hmac-sha-04.txt 
Network Working Group D. Zhang Network Working Group D. Zhang
Internet-Draft Huawei Internet-Draft Huawei
Intended status: Standards Track M. Bhatia Intended status: Standards Track M. Bhatia
Expires: October 20, 2013 Alcatel-Lucent Expires: April 18, 2014 Alcatel-Lucent
V. Manral V. Manral
Hewlett-Packard Co. Hewlett-Packard Co.
April 18, 2013 October 15, 2013
Authenticating BFD using HMAC-SHA-2 procedures Authenticating BFD using HMAC-SHA-2 procedures
draft-ietf-bfd-hmac-sha-03 draft-ietf-bfd-hmac-sha-04
Abstract Abstract
This document describes the mechanism to authenticate Bidirectional This document describes the mechanism to authenticate Bidirectional
Forwarding Detection (BFD) protocol packets using Hashed Message Forwarding Detection (BFD) protocol packets using Hashed Message
Authentication Mode (HMAC) with the SHA-256, SHA-384, and SHA-512 Authentication Mode (HMAC) with the SHA-256, SHA-384, and SHA-512
algorithms. The described mechanism uses the Generic Cryptographic algorithms. The described mechanism uses the Generic Cryptographic
Authentication and Generic Meticulous Cryptographic Authentication Authentication and Generic Meticulous Cryptographic Authentication
sections to carry the authentication data. This document updates, sections to carry the authentication data. This document updates,
but does not supercede, the cryptographic authentication mechanism but does not supercede, the cryptographic authentication mechanism
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 20, 2013. This Internet-Draft will expire on April 18, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
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Implementations of this specification must include support for at Implementations of this specification must include support for at
least HMAC-SHA-256 and may include support for either of HMAC-SHA-384 least HMAC-SHA-256 and may include support for either of HMAC-SHA-384
or HMAC-SHA-512. or HMAC-SHA-512.
2. Cryptographic Aspects 2. Cryptographic Aspects
In the algorithm description below, the following nomenclature, which In the algorithm description below, the following nomenclature, which
is consistent with [FIPS-198], is used: is consistent with [FIPS-198], is used:
H is the specific hashing algorithm (e.g. SHA-256). H is the specific hashing algorithm (e.g. SHA-256).
K is the password for the BFD packet. K is the password for the BFD packet.
Ko is the cryptographic key used with the hash algorithm. Ko is the cryptographic key used with the hash algorithm.
B is the block size of H, measured in octets rather than bits. Note B is the block size of H, measured in octets rather than bits. Note
that B is the internal block size, not the hash size. For SHA-1 and that B is the internal block size, not the hash size. For SHA-1 and
SHA-256: B == 64 For SHA-384 and SHA-512: B == 128 L is the length of SHA-256: B == 64 For SHA-384 and SHA-512: B == 128 L is the length of
the hash, measured in octets rather than bits. the hash, measured in octets rather than bits.
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Ipad is the hexadecimal value 0x36 repeated B times. Ipad is the hexadecimal value 0x36 repeated B times.
Apad is the hexadecimal value 0x878FE1F3 repeated (L/4) times. Apad is the hexadecimal value 0x878FE1F3 repeated (L/4) times.
(1) Preparation of the Key (1) Preparation of the Key
In this application, Ko is always L octets long. In this application, Ko is always L octets long.
If the Authentication Key (K) is L octets long, then Ko is equal to If the Authentication Key (K) is L octets long, then Ko is equal to
K. If the Authentication Key (K) is more than L octets long, then Ko K. If the Authentication Key (K) is more than L octets long, then Ko
is set to H(K). If the Authentication Key (K) is less than L octets is set to H(K). If the Authentication Key (K) is less than L octets
long, then Ko is set to the Authentication Key (K) with zeros long, then Ko is set to the Authentication Key (K) with zeros
appended to the end of the Authentication Key (K) such that Ko is L appended to the end of the Authentication Key (K) such that Ko is L
octets long. octets long.
(2) First Hash (2) First Hash
First, the Authentication Data field in the Generic Authentication First, the Authentication Data field in the Generic Authentication
Section is filled with the value of Apad and the Authentication Type Section is filled with the value of Apad and the Authentication Type
field is set to 6 or 7 depending upon which Authentication Type is field is set to 6 or 7 depending upon which Authentication Type is
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(HMAC)", August 2002. (HMAC)", August 2002.
[FIPS-198] [FIPS-198]
National Institute of Standards and Technology, FIPS PUB National Institute of Standards and Technology, FIPS PUB
198, "The Keyed-Hash Message Authentication Code (HMAC)", 198, "The Keyed-Hash Message Authentication Code (HMAC)",
March 2002. March 2002.
[I-D.ietf-bfd-generic-crypto-auth] [I-D.ietf-bfd-generic-crypto-auth]
Bhatia, M., Manral, V., and D. Zhang, "BFD Generic Bhatia, M., Manral, V., and D. Zhang, "BFD Generic
Cryptographic Authentication", draft-ietf-bfd-generic- Cryptographic Authentication", draft-ietf-bfd-generic-
crypto-auth-03 (work in progress), October 2012. crypto-auth-04 (work in progress), April 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC6039] Manral, V., Bhatia, M., Jaeggli, J., and R. White, "Issues [RFC6039] Manral, V., Bhatia, M., Jaeggli, J., and R. White, "Issues
with Existing Cryptographic Protection Methods for Routing with Existing Cryptographic Protection Methods for Routing
Protocols", RFC 6039, October 2010. Protocols", RFC 6039, October 2010.
[RFC6151] Turner, S. and L. Chen, "Updated Security Considerations [RFC6151] Turner, S. and L. Chen, "Updated Security Considerations
for the MD5 Message-Digest and the HMAC-MD5 Algorithms", for the MD5 Message-Digest and the HMAC-MD5 Algorithms",
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