Internet Engineering Task Force (IETF)                            L. Law
Request for Comments: 6379                                    J. Solinas
Obsoletes: 4869                                                      NSA
Category: Informational                                     October 2011
ISSN: 2070-1721


                 Suite B Cryptographic Suites for IPsec

Abstract

   This document proposes four cryptographic user interface suites
   ("UI suites") for IP Security (IPsec), similar to the two suites
   specified in RFC 4308.  The four new suites provide compatibility
   with the United States National Security Agency's Suite B
   specifications.  This document obsoletes RFC 4869, which presented
   earlier versions of these suites.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6379.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   publication of this document.  Please review these documents
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................2
   2. Requirements Terminology ........................................2
   3. New UI Suites ...................................................2
      3.1. Suite "Suite-B-GCM-128" ....................................3
      3.2. Suite "Suite-B-GCM-256" ....................................3
      3.3. Suite "Suite-B-GMAC-128" ...................................4
      3.4. Suite "Suite-B-GMAC-256" ...................................4
   4. Security Considerations .........................................4
   5. IANA Considerations .............................................5
   6. Changes from RFC 4869 ...........................................5
   7. References ......................................................5
      7.1. Normative References .......................................5
      7.2. Informative References .....................................6

1.  Introduction

   [RFC4308] proposes two optional cryptographic user interface suites
   ("UI suites") for IPsec.  The two suites, VPN-A and VPN-B, represent
   commonly used present day corporate VPN security choices and
   anticipated future choices, respectively.  [RFC4869] proposed four
   new UI suites based on implementations of the United States National
   Security Agency's Suite B algorithms (see [SuiteB]).

   As with the VPN suites, the Suite B suites are simply collections of
   values for some options in IPsec.  Use of UI suites does not change
   the IPsec protocols in any way.

   This document reduces the scope of the suites in [RFC4869] while
   retaining the original suite names.  A detailed list of the changes
   is given in Section 6.  This document obsoletes RFC 4869.

2.  Requirements Terminology

   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 [RFC2119].

3.  New UI Suites

   Each of the following UI suites provides choices for ESP (see
   [RFC4303]) and for Internet Key Exchange (IKEv2) (see [RFC5996]).
   The four suites are differentiated by the choice of cryptographic
   algorithm strengths, and a choice of whether the Encapsulating
   Security Payload (ESP) is to provide both confidentiality and
   integrity or integrity only.  The suite names are based on the

   Advanced Encryption Standard [AES] mode and AES key length specified
   for ESP.

   IPsec implementations that use these UI suites MUST use the suite
   names listed here.  IPsec implementations SHOULD NOT use names
   different than those listed here for the suites that are described,
   and MUST NOT use the names listed here for suites that do not match
   these values.  These requirements are necessary for interoperability.

3.1.  Suite "Suite-B-GCM-128"

   This suite provides ESP integrity protection and confidentiality
   using 128-bit AES-GCM (see [RFC4106]).  This suite or the following
   suite should be used when ESP integrity protection and encryption are
   both needed.

   ESP:
     Encryption     AES with 128-bit keys and 16-octet Integrity
                      Check Value (ICV) in GCM mode [RFC4106]
     Integrity      NULL

   IKEv2:
     Encryption                   AES with 128-bit keys in CBC mode
                                    [RFC3602]
     Pseudo-random function       HMAC-SHA-256 [RFC4868]
     Integrity                    HMAC-SHA-256-128 [RFC4868]
     Diffie-Hellman group         256-bit random ECP group [RFC5903]

3.2.  Suite "Suite-B-GCM-256"

   This suite provides ESP integrity protection and confidentiality
   using 256-bit AES-GCM (see [RFC4106]).  This suite or the preceding
   suite should be used when ESP integrity protection and encryption are
   both needed.

   ESP:
     Encryption     AES with 256-bit keys and 16-octet ICV in GCM mode
                      [RFC4106]
     Integrity      NULL

   IKEv2:
     Encryption                   AES with 256-bit keys in CBC mode
                                    [RFC3602]
     Pseudo-random function       HMAC-SHA-384 [RFC4868]
     Integrity                    HMAC-SHA-384-192 [RFC4868]
     Diffie-Hellman group         384-bit random ECP group [RFC5903]

3.3.  Suite "Suite-B-GMAC-128"

   This suite provides ESP integrity protection using 128-bit AES-GMAC
   (see [RFC4543]) but does not provide confidentiality.  This suite or
   the following suite should be used only when there is no need for ESP
   encryption.

   ESP:
     Encryption     NULL
     Integrity      AES with 128-bit keys in GMAC mode [RFC4543]

   IKEv2:
     Encryption                   AES with 128-bit keys in CBC mode
                                    [RFC3602]
     Pseudo-random function       HMAC-SHA-256 [RFC4868]
     Integrity                    HMAC-SHA-256-128 [RFC4868]
     Diffie-Hellman group         256-bit random ECP group [RFC5903]

3.4.  Suite "Suite-B-GMAC-256"

   This suite provides ESP integrity protection using 256-bit AES-GMAC
   (see [RFC4543]) but does not provide confidentiality.  This suite or
   the preceding suite should be used only when there is no need for ESP
   encryption.

   ESP:
     Encryption     NULL
     Integrity      AES with 256-bit keys in GMAC mode [RFC4543]

   IKEv2:
     Encryption                   AES with 256-bit keys in CBC mode
                                    [RFC3602]
     Pseudo-random function       HMAC-SHA-384 [RFC4868]
     Integrity                    HMAC-SHA-384-192 [RFC4868]
     Diffie-Hellman group         384-bit random ECP group [RFC5903]

4.  Security Considerations

   This document inherits all of the security considerations of the
   IPsec and IKEv2 documents.

   Some of the security options specified in these suites may be found
   in the future to have properties significantly weaker than those that
   were believed at the time this document was produced.

5.  IANA Considerations

   IANA maintains a registry called "Cryptographic Suites for IKEv1,
   IKEv2, and IPsec" (see [IANA-Suites]).  The registry consists of a
   text string and an RFC number that lists the associated transforms.
   The four suites in this document have been listed with this document
   as the RFC reference.  These entries will be updated upon approval of
   this document.

   The updated values for the registry are:

   Identifier              Defined in
   Suite-B-GCM-128         RFC 6379
   Suite-B-GCM-256         RFC 6379
   Suite-B-GMAC-128        RFC 6379
   Suite-B-GMAC-256        RFC 6379

6.  Changes from RFC 4869

   The changes from [RFC4869] are:

   1. Removed definitions of the suites for IKEv1.

   2. Removed IKE authentication methods from the suite definitions.
      These now appear in [RFC6380].

   3. Removed the requirements on rekeying in IKEv2.

7.  References

7.1.  Normative References

   [IANA-Suites] Internet Assigned Numbers Authority, "Cryptographic
                 Suites for IKEv1, IKEv2, and IPsec",
                 <http://www.iana.org/assignments/crypto-suites>.

   [RFC2119]     Bradner, S., "Key words for use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3602]     Frankel, S., Glenn, R., and S. Kelly, "The AES-CBC
                 Cipher Algorithm and Its Use with IPsec", RFC 3602,
                 September 2003.

   [RFC4106]     Viega, J. and D. McGrew, "The Use of Galois/Counter
                 Mode (GCM) in IPsec Encapsulating Security Payload
                 (ESP)", RFC 4106, June 2005.

   [RFC4303]     Kent, S., "IP Encapsulating Security Payload (ESP)",
                 RFC 4303, December 2005.

   [RFC4308]     Hoffman, P., "Cryptographic Suites for IPsec", RFC
                 4308, December 2005.

   [RFC4543]     McGrew, D. and J. Viega, "The Use of Galois Message
                 Authentication Code (GMAC) in IPsec ESP and AH", RFC
                 4543, May 2006.

   [RFC4868]     Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-
                 SHA-384, and HMAC-SHA-512 with IPsec", RFC 4868, May
                 2007.

   [RFC4869]     Law, L. and J. Solinas, "Suite B Cryptographic Suites
                 for IPsec", RFC 4869, May 2007.

   [RFC5903]     Fu, D. and J. Solinas, "Elliptic Curve Groups modulo a
                 Prime (ECP Groups) for IKE and IKEv2", RFC 5903, June
                 2010.

   [RFC5996]     Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
                 "Internet Key Exchange Protocol Version 2 (IKEv2)", RFC
                 5996, September 2010.

7.2.  Informative References

   [AES]         U.S. Department of Commerce/National Institute of
                 Standards and Technology, "Advanced Encryption Standard
                 (AES)", FIPS PUB 197, November 2001,
                 <http://csrc.nist.gov/publications/fips/index.html>.

   [RFC6380]     Burgin, K. and M. Peck, "Suite B Profile for Internet
                 Protocol Security (IPsec)", RFC 6380, October 2011.

   [SuiteB]      U.S. National Security Agency, "NSA Suite B
                 Cryptography", January 2009, <http://www.nsa.gov/
                 ia/programs/suiteb_cryptography/>.

Authors' Addresses

   Laurie E. Law
   National Security Agency

   EMail: lelaw@orion.ncsc.mil


   Jerome A. Solinas
   National Security Agency

   EMail: jasolin@orion.ncsc.mil