Internet DRAFT - draft-avt-kanno-srtp-camellia


Network Working Group                                           S. Kanno
Internet-Draft                                  NTT Software Corporation
Intended status: Standards Track                                M. Kanda
Expires: September 27, 2010                                          NTT
                                                          March 26, 2010

 The Camellia Algorithm and Its Use with the Secure Real-time Transport


   This document describes the use of the Camellia block cipher
   algorithm in the Secure Real-time Transport Protocol (SRTP) for
   providing confidentiality for the Real-time Transport Protocol (RTP)
   traffic and for the control traffic for RTP, the Real-time Transport
   Control Protocol (RTCP).

Status of this Memo

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   Copyright (c) 2010 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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   Provisions Relating to IETF Documents
   ( in effect on the date of
   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 BSD License.

1.  Introduction

   This document describes the use of the Camellia [RFC3713] block
   cipher algorithm in the Secure Real-time Transport Protocol (SRTP)
   [RFC3711] for providing confidentiality for the Real-time Transport
   Protocol (RTP) [RFC3550] traffic and for the control traffic for RTP,
   the Real-time Transport Control Protocol (RTCP) [RFC3550].

1.1.  Camellia

   Camellia is a symmetric cipher with a Feistel structure.  Camellia
   was developed jointly by NTT and Mitsubishi Electric Corporation in
   2000.  It was designed to withstand all known cryptanalytic attacks,
   and it has been scrutinized by worldwide cryptographic experts.
   Camellia is suitable for implementation in software and hardware,
   offering encryption speed in software and hardware implementations
   that is comparable to Advanced Encryption Standard (AES)

   Camellia supports 128-bit block size and 128-, 192-, and 256-bit key
   lengths, i.e., the same interface specifications as the AES.
   Therefore, it is easy to implement Camellia based algorithms by
   replacing the AES block of AES based algorithms with a Camellia

   Camellia already has been adopted by the IETF and other international
   standardization organizations; in particular, the IETF has published
   specifications for the use of Camellia with IPsec [RFC4312], TLS
   [RFC4132], S/MIME [RFC3657] and XML Security [RFC4051].  Camellia is
   one of the three ISO/IEC international standard [ISO/IEC 18033-3]
   128-bit block ciphers (Camellia, AES, and SEED).  Camellia was
   selected as a recommended cryptographic primitive by the EU NESSIE
   (New European Schemes for Signatures, Integrity and Encryption)
   project [NESSIE] and was included in the list of cryptographic
   techniques for Japanese e-Government systems that was selected by the
   Japanese CRYPTREC (Cryptography Research and Evaluation Committees)

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   Since optimized source code is provided under several open source
   licenses [open source license], Camellia is also adopted by several
   open source projects (OpenSSL, GnuTLS, FreeBSD, and Linux).  Camellia
   is also adopted by Mozilla and Camellia is ready for use with Firefox
   3.0 released in June 2008.

   The algorithm specification and object identifiers are described in

   The Camellia web site [Camellia web site] contains a wealth of
   information about Camellia, including detailed specification,
   security analysis, performance figures, reference implementation,
   optimized implementation, test vectors(TV), and intellectual property

1.2.  Terminology

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   appear in this document are to be interpreted as described in

2.  Camellia Algorithm Suites for SRTP

   All symmetric block cipher algorithms share common characteristics
   and valuables, including mode, key size, weak keys, and block size.
   Camellia algorithm is specified as well as AES, those relations are

        - Camellia-CTR complies with [RFC3711]

3.  Default and mandatory-to-implement Transforms

   The default transforms also are mandatory-to-implement transforms in
   SRTP.  Of course, "mandatory-to-implement" does not imply "mandatory-
   to-use".  Table 1 summarizes the pre-defined transforms.  The default
   values below are valid for the pre-defined transforms.

                           man.-to-impl.    default
      encryption           Camellia-CTR     Camellia-CTR
      message integrity    HMAC-SHA1        HMAC-SHA1
      key derivation (PRF) Camellia-CTR     Camellia-CTR

   Table 1: Mandatory-to-implement and default transforms in SRTP and

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4.  Security Considerations

   At the time of writing this document there are no known weak keys for
   Camellia.  And no security problem has been found on Camellia (see
   [NESSIE], [CRYPTREC], and [LNCS]).

   The security considerations in RFC 5289 [RFC3711] apply to this
   document as well.

5.  IANA Considerations

   RFC 4568 [RFC4568] defines SRTP "crypto suites"; In order to allow
   SDP to signal the use of the algorithms defined in this document,
   IANA will register the following crypto suites into the subregistry
   for SRTP crypto suites under the SRTP transport of the SDP Security

         srtp-crypto-suite-ext = "CAMELLIA_CTR_128_HMAC_SHA1_80" /
                                 "CAMELLIA_CTR_128_HMAC_SHA1_32" /

6.  Test Vectors

6.1.  Camellia-CTR Test Vectors

    Keystream segment length: 1044512 octets (65282 Camellia blocks)
    Session Key:      2B7E151628AED2A6ABF7158809CF4F3C
    Rollover Counter: 00000000
    Sequence Number:  0000
    SSRC:             00000000
    Session Salt:     F0F1F2F3F4F5F6F7F8F9FAFBFCFD0000 (already shifted)
    Offset:           F0F1F2F3F4F5F6F7F8F9FAFBFCFD0000

    Counter                            Keystream

    F0F1F2F3F4F5F6F7F8F9FAFBFCFD0000   B2D8ED5E9E74E2B22F24D190290304F1
    F0F1F2F3F4F5F6F7F8F9FAFBFCFD0001   917D4D59E7A62AAA3EC3037481304FAC
    F0F1F2F3F4F5F6F7F8F9FAFBFCFD0002   876DDA20079D808ABE045C84FFA50E6B
    ...                                ...
    F0F1F2F3F4F5F6F7F8F9FAFBFCFDFF00   156C6C1985F2DA529B6377C760295A98
    F0F1F2F3F4F5F6F7F8F9FAFBFCFDFF01   7920339AFE329CBA9DE8A2FC0D8BAE74

6.2.  Key Derivation Test Vectors using Camellia-128 in Counter Mode

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   master key:  E1F97A0D3E018BE0D64FA32C06DE4139
   master salt: 0EC675AD498AFEEBB6960B3AABE6

 (1) session key

      index DIV kdr: 000000000000
      label:         00
      master salt:   0EC675AD498AFEEBB6960B3AABE6
      xor:        0EC675AD498AFEEBB6960B3AABE6     (x, PRF input)

      x*2^16:     0EC675AD498AFEEBB6960B3AABE60000 (Camellia-CTR input)

      cipher key: 259EA7329BD8BCFC0E42D6336F7EC339 (Camellia-CTR output)

 (2) session salt

      index DIV kdr: 000000000000
      label:         02
      master salt:   0EC675AD498AFEEBB6960B3AABE6

      xor:        0EC675AD498AFEE9B6960B3AABE6     (x, PRF input)

      x*2^16:     0EC675AD498AFEE9B6960B3AABE60000 (Camellia-CTR input)

                  69AF5169A7C7D257D0A19C38D81DF16A (Camellia-CTR ouptut)

      cipher salt:   69AF5169A7C7D257D0A19C38D81D

 (3) auth key

      index DIV kdr:   000000000000
      label:           01
      master salt:     0EC675AD498AFEEBB6960B3AABE6
      xor:        0EC675AD498AFEEAB6960B3AABE6     (x, PRF input)

      x*2^16:     0EC675AD498AFEEAB6960B3AABE60000 (Camellia-CTR input)

   akey                               Camellia input blocks
   CA06DDE96B5B0C71F02F878B8D376FCC   0EC675AD498AFEEAB6960B3AABE60000
   83750D2E61365F8BE33E6DD24519C5A8   0EC675AD498AFEEAB6960B3AABE60001
   17CE96CF61AB9C4F4EEB0689148A7A32   0EC675AD498AFEEAB6960B3AABE60002
   0FD78D243DDE852CA7C266D50E077CA7   0EC675AD498AFEEAB6960B3AABE60003
   BBCBF3EF45BCE67141ABA950063CF86E   0EC675AD498AFEEAB6960B3AABE60004
   73513A989FC1CBC3E8E11FF0DD20       0EC675AD498AFEEAB6960B3AABE60005

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7.  References

7.1.  Normative References

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

   [RFC3550]  Schulzrinne, H., Casner, S., Frederick, R., and V.
              Jacobson, "RTP: A Transport Protocol for Real-Time
              Applications", STD 64, RFC 3550, July 2003.

   [RFC3711]  Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
              Norrman, "The Secure Real-time Transport Protocol (SRTP)",
              RFC 3711, March 2004.

   [RFC3713]  Matsui, M., Nakajima, J., and S. Moriai, "A Description of
              the Camellia Encryption Algorithm", RFC 3713, April 2004.

   [RFC4568]  Andreasen, F., Baugher, M., and D. Wing, "Session
              Description Protocol (SDP) Security Descriptions for Media
              Streams", RFC 4568, July 2006.

7.2.  Informative References

              Information-technology Promotion Agency (IPA),
              "Cryptography Research and Evaluation Committees",

   [Camellia web site]
              "Camellia web site",

              National Institute of Standards and Technology, "Advanced
              Encryption Standard (AES)", FIPS PUB 197, November 2001, <

   [ISO/IEC 18033-3]
              International Organization for Standardization,
              "Information technology - Security techniques - Encryption
              algorithms - Part 3: Block ciphers", ISO/IEC 18033-3,
              July 2005.

   [LNCS]     Mala, H., Shakiba, M., and M. Dakhil-alian, "New Results
              on Impossible Differential Cryptanalysis of Reduced Round
              Camellia-128", November 2009,

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   [NESSIE]   "The NESSIE project (New European Schemes for Signatures,
              Integrity and Encryption)",

   [RFC3657]  Moriai, S. and A. Kato, "Use of the Camellia Encryption
              Algorithm in Cryptographic Message Syntax (CMS)",
              RFC 3657, January 2004.

   [RFC4051]  Eastlake, D., "Additional XML Security Uniform Resource
              Identifiers (URIs)", RFC 4051, April 2005.

   [RFC4132]  Moriai, S., Kato, A., and M. Kanda, "Addition of Camellia
              Cipher Suites to Transport Layer Security (TLS)",
              RFC 4132, July 2005.

   [RFC4312]  Kato, A., Moriai, S., and M. Kanda, "The Camellia Cipher
              Algorithm and Its Use With IPsec", RFC 4312,
              December 2005.

   [open source license]
              "Camellia open source software",

Authors' Addresses

   Satoru Kanno
   NTT Software Corporation

   Phone: +81-45-212-9803
   Fax:   +81-45-212-9800

   Masayuki Kanda

   Phone: +81-422-59-3456
   Fax:   +81-422-59-4015

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