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.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsolete 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-Drafts Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
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
Moriai,Okazaki,Kato [Page 1]
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
Moriai,Okazaki,Kato [Page 2]
Internet-Draft The Use of Camellia with IPsec October 2003
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
Moriai,Okazaki,Kato [Page 3]
Internet-Draft The Use of Camellia with IPsec October 2003
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
Moriai,Okazaki,Kato [Page 4]
Internet-Draft The Use of Camellia with IPsec October 2003
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]
Moriai,Okazaki,Kato [Page 5]
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
Moriai,Okazaki,Kato [Page 6]
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
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights de fined in the Internet Standards process must be
followed, or as re quired to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS 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
MERCHANT ABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Moriai,Okazaki,Kato [Page 7]
