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Versions: 00 01                                                         
Internet Draft                                       IPsec Working Group
October 2003                                                   S. Moriai
Expiration Date: March 2004             Sony Computer Entertainment Inc.
                                                              S. Okazaki
                        NTT Multimedia Communications Laboratories, Inc.
                                                                 A. Kato
                                                      NTT Software Corp.

          The Camellia Cipher Algorithm and Its Use With IPsec
                <draft-ietf-ipsec-ciph-camellia-01.txt>

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.  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.

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   This document is a submission to the IETF Internet Protocol Security
   (IPSEC) Working Group. Comments are solicited and should be addressed
   to the working group mailing list (ipsec@lists.tislabs.com) or to the
   editors.

   Distribution of this memo is unlimited.

Abstract

   This document describes the use of the Camellia block cipher
   algorithm in Cipher Block Chaining Mode, with an explicit IV, as
   a confidentiality mechanism within the context of the IPsec
   Encapsulating Security Payload (ESP).

1. Introduction

   This document describes the use of the Camellia block cipher
   algorithm in Cipher Block Chaining Mode, with an explicit IV, as a
   confidentiality mechanism within the context of the IPsec
   Encapsulating Security Payload (ESP).

   Camellia was selected as a recommended cryptographic primitive  by
   the EU NESSIE (New European Schemes for Signatures, Integrity and
   Encryption) project [NESSIE] and included in the list of

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Internet-Draft        The Use of Camellia with IPsec        October 2003

   cryptographic techniques for Japanese e-Government systems which were
   selected by the Japan CRYPTREC (Cryptography Research and Evaluation
   Committees) [CRYPTREC].  Camellia has been submitted to other several
   standardization bodies such as ISO (ISO/IEC 18033) , IETF Transport
   Layer Security working group [Camellia-TLS] and S/MIME Mail Security
   [Camellia-SMIME] and it is under consideration.

   Camellia supports 128-bit block size and 128-, 192-, and 256-bit key
   lengths, i.e. the same interface specifications as the Advanced
   Encryption Standard (AES) [AES].

   Camellia was jointly developed by NTT and Mitsubishi Electric
   Corporation in 2000. It was carefully designed to withstand all known
   cryptanalytic attacks and even to have a sufficiently large security
   leeway for use of the next 10-20 years. It has been scrutinized by
   worldwide cryptographic experts.

   Camellia was also designed to have suitability for both software and
   hardware implementations and to cover all possible encryption
   applications that range from low-cost smart cards to high-speed
   network systems.  Compared to the AES, Camellia offers at least
   comparable encryption speed in software and hardware.  An optimized
   implementation of Camellia in assembly language can encrypt on a
   Pentium III (1.13GHz) at the rate of 471 Mbits per second.  In
   addition, a distinguishing feature is its small hardware design. The
   current smallest hardware implementation, which includes encryption,
   decryption, and the key schedule for 128-bit keys, occupies only
   8.12K gates using a 0.18um CMOS ASIC library [Camellia].  This is in
   the smallest class among all existing 128-bit block ciphers.  It
   perfectly meets one of the current IPsec market requirements, where
   low power consumption is a mandatory condition.

   The remainder of this document specifies the use of Camellia within
   the context of IPsec ESP.  For further information on how the various
   pieces of ESP fit together to provide security services, please refer
   to [ARCH], [ESP], and [ROAD].

1.1 Specification of Requirements

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" that
   appear in this document are to be interpreted as described in
   [RFC-2119].

2. The Camellia Cipher Algorithm

   All symmetric block cipher algorithms share common characteristics
   and variables, including mode, key size, weak keys, block size, and
   rounds.  The following sections contain descriptions of the relevant
   characteristics of Camellia.

   The algorithm specification and object identifiers are described in
   [Camellia-ID].  The Camellia homepage,
   http://info.isl.ntt.co.jp/camellia/, contains a wealth of information

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   about camellia, including detailed specification, security analysis,
   performance figures, reference implementation, test vectors, and
   intellectual property information.

2.1 Mode

   NIST has defined 5 modes of operation for AES and other FIPS-approved
   ciphers [MODES]: CBC (Cipher Block Chaining), ECB (Electronic
   CodeBook), CFB (Cipher FeedBack), OFB (Output FeedBack) and CTR
   (Counter).  The CBC mode is well-defined and well-understood for
   symmetric ciphers, and is currently required for all other ESP
   ciphers.  This document specifies the use of the Camellia cipher in
   CBC mode within ESP.  This mode requires an Initialization Vector (IV)
   that is the same size as the block size.  Use of a randomly generated
   IV prevents generation of identical ciphertext from packets which
   have identical data that spans the first block of the cipher
   algorithm's block size.

   The IV is XOR'd with the first plaintext block before it is
   encrypted.  Then for successive blocks, the previous ciphertext block
   is XOR'd with the current plaintext, before it is encrypted.

   More information on CBC mode can be obtained in [MODES, CRYPTO-S].
   For the use of CBC mode in ESP with 64-bit ciphers, please see [CBC].

2.2 Key Size

   Camellia supports three key sizes: 128 bits, 192 bits, and 256 bits.
   The default key size is 128 bits, and all implementations MUST
   support this key size.  Implementations MAY also support key sizes of
   192 bits and 256 bits.

   Camellia uses a different number of rounds for each of the defined
   key sizes.  When a 128-bit key is used, implementations MUST use 18
   rounds.  When a 192-bit key is used, implementations MUST use 24
   rounds.  When a 256-bit key is used, implementations MUST use 24
   rounds.

2.3 Weak Keys

   At the time of writing this document there are no known weak keys for
   Camellia.

2.4 Block Size and Padding

   Camellia uses a block size of sixteen octets (128 bits).

   Padding is required by the algorithms to maintain a 16-octet
   (128-bit) blocksize.  Padding MUST be added, as specified in [ESP],
   such that the data to be encrypted (which includes the ESP Pad Length
   and Next Header fields) has a length that is a multiple of 16 octets.

   Because of the algorithm specific padding requirement, no additional
   padding is required to ensure that the ciphertext terminates on a

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   4-octet boundary (i.e. maintaining a 16-octet blocksize guarantees
   that the ESP Pad Length and Next Header fields will be right aligned
   within a 4-octet word).  Additional padding MAY be included, as
   specified in [ESP], as long as the 16-octet blocksize is maintained.

2.6 Performance

   Performance figures of Camellia are available at
   http://info.isl.ntt.co.jp/camellia/. It also includes performance
   comparison with the AES cipher and other AES finalists.
   [NESSIE] project has reported performance of Optimized Implementations
   independently.

3. ESP Payload

   Camellia was designed to follow the same API as the AES cipher.
   Therefore, any consideration related to ESP payload is the same as
   that of the AES cipher. Details can be found in [AES-IPSEC].

4. Interaction with IKE

   Camellia was designed to follow the same API as the AES cipher.
   Therefore, this section defines only Phase 1 Identifier and Phase 2
   Identifier.  Any other consideration related to interaction with IKE
   is the same as that of the AES cipher.  Details can be found in
   [AES-IPSEC].

4.1 Phase 1 Identifier

   For Phase 1 negotiations, IANA has assigned an Encryption Algorithm
   ID of (TBD) for CAMELLIA-CBC.

4.2 Phase 2 Identifier

   For Phase 2 negotiations, IANA has assigned an ESP Transform
   Identifier of [TBD] for ESP_CAMELLIA.

5. Security Considerations

   Implementations are encouraged to use the largest key sizes they can
   when taking into account performance considerations for their
   particular hardware and software configuration.  Note that encryption
   necessarily impacts both sides of a secure channel, so such
   consideration must take into account not only the client side, but
   the server as well.  However, a key size of 128 bits is considered
   secure for the foreseeable future.

   No security problem has been found on Camellia [CRYPTREC][NESSIE].

6. Intellectual Property Statement

   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described

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   in this document or the extent to which any license under such
   rights might or might not be available; neither does it represent
   that it has made any effort to identify any such rights.
   Information on the IETF's procedures with respect to rights in
   standards-track and standards-related documentation can be found
   in BCP-11.  Copies of claims of rights made available for
   publication 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 implementors
   or users of this specification can be obtained from the IETF
   Secretariat.

   The IETF invites any interested party to bring to its attention
   any copyrights, patents or patent applications, or other
   proprietary rights which may cover technology that may be required
   to practice this standard.  Please address the information to the
   IETF Executive Director.

   The IETF has been notified of intellectual property rights
   claimed in regard to some or all of the specification contained in
   this document.  For more information consult the online list of
   claimed rights.

7. References

     [AES]       NIST, FIPS PUB 197, "Advanced Encryption Standard
                 (AES)," November 2001.
                 http://csrc.nist.gov/publications/fips/fips197/
                 fips-197.{ps,pdf}.

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

     [ARCH]      Kent, S. and R. Atkinson, "Security Architecture for
                 the Internet Protocol", RFC 2401, November 1998.

     [Camellia]  Aoki, K, T. Ichikawa, M. Kanda, M. Matsui, S. Moriai,
                 J. Nakajima, and T. Tokita, "Camellia: A 128-Bit Block
                 Cipher Suitable for Multiple Platforms,'' September,
                 2001, http://info.isl.ntt.co.jp/camellia/CRYPTREC/
                 2001/01eeval.pdf.

     [Camellia-ID]
                 Nakajima, J. and S. Moriai, "A Description of the
                 Camellia Encryption Algorithm," draft-nakajima-
                 camellia-02.txt, July, 2001.

     [Camellia-TLS]
                 Moriai, S., "Addition of the Camellia Encryption
                 Algorithm to TLS," draft-ietf-tls-camellia-03.txt,
                 June, 2003.

     [Camellia-SMIME]

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Internet-Draft        The Use of Camellia with IPsec        October 2003

                 Moriai, S. and Kato, A., "Use of the Camellia
                 Encryption Algorithm in CMS",
                 draft-ietf-smime-camellia-05.txt, August 2003.

     [CBC]       Pereira, R. and R. Adams, "The ESP CBC-Mode Cipher
                 Algorithms," RFC 2451, November 1998.

     [CRYPTO-S]  Schneier, B., "Applied Cryptography Second Edition",
                 John Wiley & Sons, New York, NY, 1995, ISBN
                 0-471-12845-7.

     [CRYPTREC]  Information-technology Promotion Agency (IPA), Japan,
                 CRYPTREC.
                 http://www.ipa.go.jp/security/enc/CRYPTREC/
                 index-e.html.

     [DOI]       Piper, D., "The Internet IP Security Domain of
                 Interpretation for ISAKMP," RFC 2407, November 1998.

     [ESP]       Kent, S. and R. Atkinson, "IP Encapsulating Security
                 Payload (ESP)", RFC 2406, November 1998.

     [IKE]       Harkins, D. and D. Carrel, "The Internet Key Exchange
                 (IKE)", RFC 2409, November 1998.

     [MODES]     Symmetric Key Block Cipher Modes of Operation,
                 http://www.nist.gov/modes/.

     [NESSIE]    The NESSIE project (New European Schemes for
                 Signatures, Integrity and Encryption),
                 http://www.cosic.esat.kuleuven.ac.be/nessie/.

     [RFC-2026]  Bradner, S., "The Internet Standards Process --
                 Revision 3", RFC2026, October 1996.

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

     [ROAD]      Thayer, R., N. Doraswamy and R. Glenn, "IP Security
                 Document Roadmap", RFC 2411, November 1998.

8. Authors' Addresses


   Shiho Moriai
   Sony Computer Entertainment Inc.
   Phone: +81-3-6438-7523
   FAX:   +81-3-6438-8629
   Email: camellia@isl.ntt.co.jp (Camellia team)
          shiho@rd.scei.sony.co.jp (Shiho Moriai)

   Satomi Okazaki
   NTT Multimedia Communications Laboratories, Inc.
   250 Cambridge Avenue, Suite 300

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Internet-Draft        The Use of Camellia with IPsec        October 2003

   Palo Alto, CA 94306, USA
   Phone: +1-650-833-3631
   FAX:   +1-650-326-1878
   Email: satomi@nttmcl.com

   Akihiro Kato
   NTT Software Corporation
   Phone: +81-45-212-7404
   FAX:   +81-45-212-7410
   Email: akato@po.ntts.co.jp

9. Full Copyright Statement

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
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   The limited permissions granted above are perpetual and will not be
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Moriai,Okazaki,Kato                                             [Page 7]