Addition of Camellia Cipher Suites to Transport Layer Security (TLS)

Status of This Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright © The Internet Society (2005).

Abstract

This document proposes the addition of new cipher suites to the Transport Layer Security (TLS) protocol to support the Camellia encryption algorithm as a bulk cipher algorithm.

1. Introduction

This document proposes the addition of new cipher suites to the TLS protocol [TLS] to support the Camellia encryption algorithm as a bulk cipher algorithm. This proposal provides a new option for fast and efficient bulk cipher algorithms.

Note:

This work was done when the first author worked for NTT.

1.1. Camellia

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 cryptographic techniques for Japanese e-Government systems, which were selected by the Japan CRYPTREC (Cryptography Research and Evaluation Committees) [CRYPTREC]. Camellia is also included in specification of the TV-Anytime Forum [TV-ANYTIME]. The TV-Anytime Forum is an association of organizations that seeks to develop specifications to enable audio-visual and other services based on mass-market high-volume digital storage in consumer platforms. Camellia is specified as Cipher Suite in TLS used by Phase 1 S-7 (Bi-directional Metadata Delivery Protection) specification and S-5 (TV-Anytime Rights Management and Protection Information for Broadcast Applications) specification. Camellia has been submitted to other several standardization bodies such as ISO (ISO/IEC 18033) and IETF S/MIME Mail Security Working Group [Camellia-CMS].

   Camellia supports 128-bit block size and 128-, 192-, and 256-bit key
   sizes; 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 [CamelliaTech]. It was carefully designed to withstand all known cryptanalytic attacks and even to have a sufficiently large security leeway. It has been scrutinized by worldwide cryptographic experts.

Camellia was also designed to be suitable for both software and hardware implementations and to cover all possible encryption applications, 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. In addition, a distinguishing feature is its small hardware design. Camellia perfectly meets one of the current TLS market requirements, for which low power consumption is mandatory.

   The algorithm specification and object identifiers are described in
   [Camellia-Desc].  The Camellia homepage,
   http://info.isl.ntt.co.jp/camellia/, contains a wealth of information
   about camellia, including detailed specification, security analysis,
   performance figures, reference implementation, and test vectors.

1.2. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document (in uppercase, as shown) are to be interpreted as described in [RFC2119].

2. Proposed Cipher Suites

The new cipher suites proposed here have the following definitions:

   CipherSuite TLS_RSA_WITH_CAMELLIA_128_CBC_SHA      = { 0x00,0x41 };
   CipherSuite TLS_DH_DSS_WITH_CAMELLIA_128_CBC_SHA   = { 0x00,0x42 };
   CipherSuite TLS_DH_RSA_WITH_CAMELLIA_128_CBC_SHA   = { 0x00,0x43 };
   CipherSuite TLS_DHE_DSS_WITH_CAMELLIA_128_CBC_SHA  = { 0x00,0x44 };
   
   CipherSuite TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA  = { 0x00,0x45 };
   CipherSuite TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA  = { 0x00,0x46 };
   
   CipherSuite TLS_RSA_WITH_CAMELLIA_256_CBC_SHA      = { 0x00,0x84 };
   CipherSuite TLS_DH_DSS_WITH_CAMELLIA_256_CBC_SHA   = { 0x00,0x85 };
   CipherSuite TLS_DH_RSA_WITH_CAMELLIA_256_CBC_SHA   = { 0x00,0x86 };
   CipherSuite TLS_DHE_DSS_WITH_CAMELLIA_256_CBC_SHA  = { 0x00,0x87 };
   CipherSuite TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA  = { 0x00,0x88 };
   CipherSuite TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA  = { 0x00,0x89 };

3. Cipher Suite Definitions

3.1. Cipher

All the cipher suites described here use Camellia in cipher block chaining (CBC) mode as a bulk cipher algorithm. Camellia is a 128- bit block cipher with 128-, 192-, and 256-bit key sizes; i.e., it supports the same block and key sizes as the Advanced Encryption Standard (AES). However, this document only defines cipher suites for 128- and 256-bit keys as well as AES cipher suites for TLS [AES-TLS]. These cipher suites are efficient and practical enough for most uses, including high-security applications.

                            Key       Expanded    Effective   IV   Block
   Cipher           Type  Material  Key Material  Key Bits   Size  Size
   
   CAMELLIA_128_CBC Block   16          16          128       16    16
   CAMELLIA_256_CBC Block   32          32          256       16    16

3.2. Hash

All the cipher suites described here use SHA-1 [SHA-1] in a Hashed Message Authentication Code (HMAC) construction, as described in section 5 of [TLS].

3.3. Key Exchange

The cipher suites defined here differ in the type of certificate and key exchange method. They use the following options:

   Cipher Suite                              Key Exchange Algorithm
   
   TLS_RSA_WITH_CAMELLIA_128_CBC_SHA         RSA
   TLS_DH_DSS_WITH_CAMELLIA_128_CBC_SHA      DH_DSS
   TLS_DH_RSA_WITH_CAMELLIA_128_CBC_SHA      DH_RSA
   TLS_DHE_DSS_WITH_CAMELLIA_128_CBC_SHA     DHE_DSS
   TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA     DHE_RSA
   TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA     DH_anon
   TLS_RSA_WITH_CAMELLIA_256_CBC_SHA         RSA
   TLS_DH_DSS_WITH_CAMELLIA_256_CBC_SHA      DH_DSS
   TLS_DH_RSA_WITH_CAMELLIA_256_CBC_SHA      DH_RSA
   TLS_DHE_DSS_WITH_CAMELLIA_256_CBC_SHA     DHE_DSS
   TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA     DHE_RSA
   TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA     DH_anon

For the meanings of the terms RSA, DH_DSS, DH_RSA, DHE_DSS, DHE_RSA, and DH_anon, please refer to sections 7.4.2 and 7.4.3 of [TLS].

4. Security Considerations

It is not believed that the new cipher suites are ever less secure than the corresponding older ones. Camellia is considered secure, and it has withstood extensive cryptanalytic efforts in several open, worldwide cryptographic evaluation projects [CRYPTREC][NESSIE].

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

For other security considerations, please refer to the security considerations of the corresponding older cipher suites described in [TLS] and [AES-TLS].

5. References

5.1. Normative References

   [Camellia-Desc] Matsui, M., Nakajima, J., and S. Moriai, "A
                   Description of the Camellia Encryption Algorithm",
                   RFC 3713, April 2004.
   
   [TLS]           Dierks, T. and C. Allen, "The TLS Protocol Version
                   1.0", RFC 2246, January 1999.
   
   [RFC2119]       Bradner, S., "Key words for use in RFCs to Indicate
                   Requirement Levels", BCP 14, RFC 2119, March 1997.

5.2. Informative References

   [CamelliaTech]  Aoki, K., Ichikawa, T., Kanda, M., Matsui, M.,
                   Moriai, S., Nakajima, J., and Tokita, T., "Camellia:
                   A 128-Bit Block Cipher Suitable for Multiple
                   Platforms - Design and Analysis -", In Selected Areas
                   in Cryptography, 7th Annual International Workshop,
                   SAC 2000, August 2000, Proceedings, Lecture Notes in
                   Computer Science 2012, pp.39-56, Springer-Verlag,
                   2001.
   
   [Camellia-CMS]  Moriai, S. and A. Kato, "Use of the Camellia
                   Encryption Algorithm in Cryptographic Message Syntax
                   (CMS)", RFC 3657, January 2004.
   
   [AES]           NIST, FIPS PUB 197, "Advanced Encryption Standard
                   (AES)", November 2001.
                   http://csrc.nist.gov/publications/fips/fips197/fips-
                   197.{ps,pdf}.
   
   [AES-TLS]       Chown, P., "Advanced Encryption Standard (AES)
                   Ciphersuites for Transport Layer Security (TLS)", RFC
                   3268, June 2002.
   
   [SHA-1]         FIPS PUB 180-1, "Secure Hash Standard", National
                   Institute of Standards and Technology, U.S.
                   Department of Commerce, April 17, 1995.
   
   [CRYPTREC]      Information-technology Promotion Agency (IPA), Japan,
                   CRYPTREC,
                   http://www.ipa.go.jp/security/enc/CRYPTREC/index-
                   e.html.
   
   [NESSIE]        The NESSIE project (New European Schemes for
                   Signatures, Integrity and Encryption),
                   http://www.cosic.esat.kuleuven.ac.be/nessie/.
   
   [TV-ANYTIME]    TV-Anytime Forum, http://www.tv-anytime.org/.

Authors' Addresses

Shiho Moriai
Sony Computer Entertainment Inc.

   Phone: +81-3-6438-7523
   Fax:   +81-3-6438-8629
   EMail: shiho@rd.scei.sony.co.jp

Akihiro Kato
NTT Software Corporation

   Phone: +81-45-212-7094
   Fax:   +81-45-212-7506
   EMail: akato@po.ntts.co.jp

Masayuki Kanda
Nippon Telegraph and Telephone Corporation

   Phone: +81-46-859-2437
   Fax:   +81-46-859-3365
   EMail: kanda.masayuki@lab.ntt.co.jp
          camellia@lab.ntt.co.jp (Camellia team)

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