[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-badra-tls-psk-new-mac-aes-gcm) 00 01 02 03 04 05 RFC 5487

TLS Working Group                                         Mohamad Badra
Internet Draft                                         LIMOS Laboratory
Intended status: Standards Track                       October 31, 2008
Expires: April 2009


   Pre-Shared Key Cipher Suites for Transport Layer Security (TLS) with
                  SHA-256/384 and AES Galois Counter Mode
                 draft-ietf-tls-psk-new-mac-aes-gcm-05.txt


Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other documents
   at any time.  It is inappropriate to use Internet-Drafts as
   reference material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html

   This Internet-Draft will expire on April 31, 2009.

Copyright Notice

   Copyright (C) The IETF Trust (2008).

Abstract

   RFC 4279 and RFC 4785 describe pre-shared key cipher suites for
   Transport Layer Security (TLS).  However, all those cipher suites
   use SHA-1 as their MAC algorithm.  This document describes a set of
   pre-shared key cipher suites for TLS which uses stronger digest
   algorithms (i.e., SHA-256 or SHA-384) and another set which uses the
   Advanced Encryption Standard (AES) in Galois Counter Mode (GCM).



Badra                   Expires April 31, 2009                 [Page 1]


Internet-Draft       TLS PSK New MAC and AES-GCM           October 2008


Table of Contents


   1. Introduction...................................................3
      1.1. Applicability Statement...................................3
      1.2. Conventions used in this document.........................4
   2. PSK, DHE_PSK and RSA_PSK Key Exchange Algorithms with AES-GCM..4
   3. PSK, DHE_PSK and RSA_PSK Key Exchange with SHA-256/384.........4
      3.1. PSK Key Exchange Algorithm with SHA-256/384...............5
      3.2. DHE_PSK Key Exchange Algorithm with SHA-256/384...........5
      3.3. RSA_PSK Key Exchange Algorithm with SHA-256/384...........5
   4. Security Considerations........................................6
   5. IANA Considerations............................................6
   6. Acknowledgments................................................7
   7. References.....................................................7
      7.1. Normative References......................................7
      7.2. Informative References....................................8
   Author's Addresses................................................8
   Intellectual Property Statement...................................8
   Disclaimer of Validity............................................9





























Badra                   Expires April 31, 2009                 [Page 2]


Internet-Draft       TLS PSK New MAC and AES-GCM           October 2008


1. Introduction

   The benefits of pre-shared symmetric-key vs. public-/private-key
   pair based authentication for the key exchange in TLS have been
   explained in the Introduction of [RFC4279].  This document leverages
   the already defined algorithms for the application of newer,
   generally regarded stronger, cryptographic primitives and building
   blocks.

   TLS 1.2 [RFC5246] adds support for authenticated encryption with
   additional data (AEAD) cipher modes [RFC5116]. This document
   describes the use of Advanced Encryption Standard (AES) [AES] in
   Galois Counter Mode (GCM) [GCM] (AES-GCM) with various pre-shared
   key (PSK) authenticated key exchange mechanisms ([RFC4279] and
   [RFC4785]) in cipher suites for Transport Layer Security (TLS).

   This document also specifies PSK cipher suites for TLS which replace
   SHA-1 by SHA-256 or SHA-384 [SHS].  RFC 4279 [RFC4279] and RFC 4785
   [RFC4785] describe PSK cipher suites for TLS.  However, all of the
   RFC 4279 and the RFC 4785 cipher suites use HMAC-SHA1 as their MAC
   algorithm.  Due to recent analytic work on SHA-1 [Wang05], the IETF
   is gradually moving away from SHA-1 and towards stronger hash
   algorithms.

   Related TLS cipher suites with key exchange algorithms that are
   authenticated using public/private key pairs have recently been
   specified:

      - RSA, DSS, and Diffie-Hellman based cipher suites in [RFC5288],
        and

      - ECC based cipher suites with SHA-256/384 and AES-GCM in
        [RFC5289].

   The reader is expected to become familiar with these two memos prior
   to studying this document.

1.1. Applicability Statement

   The cipher suites defined in Section 3 can be negotiated, whatever
   the negotiated TLS version is.

   The cipher suites defined in Section 2 can be negotiated in TLS
   version 1.2 or higher.





Badra                   Expires April 31, 2009                 [Page 3]


Internet-Draft       TLS PSK New MAC and AES-GCM           October 2008


1.2. Conventions used in this document

   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].

2. PSK, DHE_PSK and RSA_PSK Key Exchange Algorithms with AES-GCM

   The following six cipher suites use the new authenticated encryption
   modes defined in TLS 1.2 with AES in Galois Counter Mode (GCM)
   [GCM].  The cipher suites with DHE_PSK key exchange algorithm
   (TLS_DHE_PSK_WITH_AES_128_GCM_SHA256 and
   TLS_DHE_PSK_WITH_AES_256_GCM_SHA348) provide Perfect Forward Secrecy
   (PFS).

      CipherSuite TLS_PSK_WITH_AES_128_GCM_SHA256        = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_AES_256_GCM_SHA384        = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_AES_128_GCM_SHA256    = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_AES_256_GCM_SHA384    = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_AES_128_GCM_SHA256    = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_AES_256_GCM_SHA384    = {0xXX,0xXX};

   These cipher suites use authenticated encryption with additional
   data (AEAD) algorithms AEAD_AES_128_GCM and AEAD_AES_256_GCM as
   described in RFC 5116.  GCM is used as described in [RFC5288].

   The PSK, DHE_PSK and RSA_PSK key exchanges are performed as defined
   in [RFC4279].

   The Pseudo Random Function (PRF) algorithms SHALL be as follows:

       For cipher suites ending with _SHA256, the PRF is the TLS PRF
       [RFC5246] with SHA-256 as the hash function.

       For cipher suites ending with _SHA384, the PRF is the TLS PRF
       [RFC5246] with SHA-384 as the hash function.

   Implementations MUST send a TLS Alert 'bad_record_mac' for all types
   of failures encountered in processing the AES-GCM algorithm.

3. PSK, DHE_PSK and RSA_PSK Key Exchange with SHA-256/384

   The first two cipher suites described in each of the following three
   sections use AES [AES] in Cipher Block Chaining (CBC) mode [CBC] for
   data confidentiality, whereas the other two cipher suites do not
   provide data confidentiality; all cipher suites provide integrity
   protection and authentication using HMAC-based MACs.


Badra                   Expires April 31, 2009                 [Page 4]


Internet-Draft       TLS PSK New MAC and AES-GCM           October 2008


3.1. PSK Key Exchange Algorithm with SHA-256/384

      CipherSuite TLS_PSK_WITH_AES_128_CBC_SHA256        = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_AES_256_CBC_SHA384        = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_NULL_SHA256               = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_NULL_SHA384               = {0xXX,0xXX};

   The above four cipher suites are the same as the corresponding
   cipher suites in RFC 4279 and RFC 4785 (with names ending in "_SHA"
   in place of "_SHA256" or "_SHA384"), except for the hash and PRF
   algorithms:

        o  For cipher suites with names ending in "_SHA256":

           -  The MAC is HMAC [RFC2104] with SHA-256 as the hash
              function.

           -  When negotiated in a version of TLS prior to 1.2, the PRF
              from that version is used; otherwise the PRF is the TLS
              PRF [RFC5246] with SHA-256 as the hash function.

        o  For cipher suites with names ending in "_SHA384":

           -  The MAC is HMAC [RFC2104] with SHA-384 as the hash
              function.

           -  When negotiated in a version of TLS prior to 1.2, the PRF
              from that version is used; otherwise the PRF is the TLS
              PRF [RFC5246] with SHA-384 as the hash function.

3.2. DHE_PSK Key Exchange Algorithm with SHA-256/384

      CipherSuite TLS_DHE_PSK_WITH_AES_128_CBC_SHA256    = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_AES_256_CBC_SHA384    = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_NULL_SHA256           = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_NULL_SHA384           = {0xXX,0xXX};

   The above four cipher suites are the same as the corresponding
   cipher suites in RFC 4279 and RFC 4785 (with names ending in "_SHA"
   in place of "_SHA256" or "_SHA384"), except for the hash and PRF
   algorithms, as explained in Section 3.1.

3.3. RSA_PSK Key Exchange Algorithm with SHA-256/384

      CipherSuite TLS_RSA_PSK_WITH_AES_128_CBC_SHA256    = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_AES_256_CBC_SHA384    = {0xXX,0xXX};



Badra                   Expires April 31, 2009                 [Page 5]


Internet-Draft       TLS PSK New MAC and AES-GCM           October 2008


      CipherSuite TLS_RSA_PSK_WITH_NULL_SHA256           = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_NULL_SHA384           = {0xXX,0xXX};

   The above four cipher suites are the same as the corresponding
   cipher suites in RFC 4279 and RFC 4785 (with names ending in "_SHA"
   in place of "_SHA256" or "_SHA384"), except for the hash and PRF
   algorithms, as explained in Section 3.1.

4. Security Considerations

   The security considerations in [RFC4279], [RFC4785] and [RFC5288]
   apply to this document as well.  In particular, as authentication-
   only cipher suites (with no encryption) defined here do not support
   confidentiality, care should be taken not to send sensitive
   information (such as passwords) over connections protected with one
   of the cipher suites with NULL encryption defined in this document.

   As described in [RFC5288], the cipher suites defined in the Section
   2 of this document may only be used with TLS 1.2 or greater. The
   cipher suites defined in the Section 3 may be used, whatever the
   negotiated TLS version is.

5. IANA Considerations

   IANA has assigned the following values for the cipher suites defined
   in this document:

      CipherSuite TLS_PSK_WITH_AES_128_GCM_SHA256        = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_AES_256_GCM_SHA384        = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_AES_128_GCM_SHA256    = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_AES_256_GCM_SHA384    = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_AES_128_GCM_SHA256    = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_AES_256_GCM_SHA384    = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_AES_128_CBC_SHA256        = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_AES_256_CBC_SHA384        = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_NULL_SHA256               = {0xXX,0xXX};
      CipherSuite TLS_PSK_WITH_NULL_SHA384               = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_AES_128_CBC_SHA256    = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_AES_256_CBC_SHA384    = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_NULL_SHA256           = {0xXX,0xXX};
      CipherSuite TLS_DHE_PSK_WITH_NULL_SHA384           = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_AES_128_CBC_SHA256    = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_AES_256_CBC_SHA384    = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_NULL_SHA256           = {0xXX,0xXX};
      CipherSuite TLS_RSA_PSK_WITH_NULL_SHA384           = {0xXX,0xXX};




Badra                   Expires April 31, 2009                 [Page 6]


Internet-Draft       TLS PSK New MAC and AES-GCM           October 2008


6. Acknowledgments

   This draft borrows heavily from [RFC5289] and [RFC5288].

   The author appreciates Alfred Hoenes for his detailed review and
   effort on issues resolving discussion.  The author would like also
   to acknowledge Ibrahim Hajjeh, Simon Josefsson, Hassnaa Moustafa,
   Joseph Salowey and Pascal Urien for their reviews of the content of
   the document.

7. References

7.1. Normative References

   [AES]     National Institute of Standards and Technology,
             "Specification for the Advanced Encryption Standard
             (AES)", FIPS 197, November 2001.

   [CBC]     National Institute of Standards and Technology,
             "Recommendation for Block Cipher Modes of Operation -
             Methods and Techniques", SP 800-38A, December 2001.

   [GCM]     National Institute of Standards and Technology,
             "Recommendation for Block Cipher Modes of Operation:
             Galois/Counter Mode (GCM) for Confidentiality and
             Authentication", SP 800-38D, November 2007.

   [SHS]     National Institute of Standards and Technology, "Secure
             Hash Standard", FIPS 180-2, August 2002.

   [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
             Hashing for Message Authentication", RFC 2104, February
             1997.

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

   [RFC4279] Eronen, P. and H. Tschofenig, "Pre-Shared Key Ciphersuites
             for Transport Layer Security (TLS)", RFC 4279, December
             2005.

   [RFC4785] Blumenthal, U., Goel, P., "Pre-Shared Key (PSK)
             Ciphersuites with NULL Encryption for Transport Layer
             Security (TLS)", RFC 4785, January 2007.

   [RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated
             Encryption", RFC 5116, January 2008.


Badra                   Expires April 31, 2009                 [Page 7]


Internet-Draft       TLS PSK New MAC and AES-GCM           October 2008


   [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
             (TLS) Protocol Version 1.2", RFC 5246, August 2008.

   [RFC5288] Salowey, J., A. Choudhury, and C. McGrew, "RSA based AES-
             GCM Cipher Suites for TLS", RFC 5288, August 2008.

7.2. Informative References

   [RFC5289] Rescorla, E., "TLS Elliptic Curve Cipher Suites with SHA-
             256/384 and AES Galois Counter Mode", RFC 5289, August
             2008.

   [Wang05]  Wang, X., Yin, Y., and H. Yu, "Finding Collisions in the
             Full SHA-1", CRYPTO 2005, August 2005.

Author's Addresses

   Mohamad Badra
   LIMOS Laboratory - UMR6158, CNRS
   France

   Email: badra@isima.fr

Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed
   to pertain to the implementation or use of the technology described
   in this document or the extent to which any license under such
   rights might or might not be available; nor does it represent that
   it has made any independent effort to identify any such rights.
   Information on the procedures with respect to rights in RFC
   documents can be found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use
   of such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository
   at http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.



Badra                   Expires April 31, 2009                 [Page 8]


Internet-Draft       TLS PSK New MAC and AES-GCM           October 2008


Disclaimer of Validity

   This document and the information contained herein are provided on
   an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
   REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE
   IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL
   WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY
   WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE
   ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
   FOR A PARTICULAR PURPOSE.

Copyright Statement

   Copyright (C) The IETF Trust (2008).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

Acknowledgment

   Funding for the RFC Editor function is currently provided by the
   Internet Society.


























Badra                   Expires April 31, 2009                 [Page 9]


Html markup produced by rfcmarkup 1.121, available from https://tools.ietf.org/tools/rfcmarkup/