Camellia in TLS: Addition of Camellia Cipher Suites to Transport Layer Security (TLS)
Adding a fast block cipher option for encrypting TLS traffic.
Moriai, S., Kato, A., and M. Kanda, "Addition of Camellia Cipher Suites to Transport Layer Security (TLS)", RFC 4132, DOI 10.17487/RFC4132, July 2005, <https://www.rfc-editor.org/info/rfc4132>.
@misc{rfc4132,
series = {Request for Comments},
number = 4132,
howpublished = {RFC 4132},
publisher = {RFC Editor},
doi = {10.17487/RFC4132},
url = {https://www.rfc-editor.org/info/rfc4132},
author = {S. Moriai and A. Kato and M. Kanda},
title = {{Addition of Camellia Cipher Suites to Transport Layer Security (TLS)}},
pagetotal = 7,
year = 2005,
month = jul,
} RFC text
Contents
Network Working Group S. Moriai
Request for Comments: 4132 Sony Computer Entertainment Inc.
Category: Standards Track A. Kato
NTT Software Corporation
M. Kanda
Nippon Telegraph and Telephone Corporation
July 2005
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 (C) 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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AI ELI5
On this page
§1Introduction and Background
RFC 4132 proposes the addition of new cipher suites to the Transport Layer Security (TLS) protocol to support the Camellia encryption algorithm as a bulk cipher. Camellia is a 128-bit block cipher that supports the same key sizes as the Advanced Encryption Standard (AES): 128, 192, and 256 bits.
Camellia was jointly developed by NTT and Mitsubishi Electric in 2000 and has been extensively evaluated by cryptographic experts worldwide. It was selected as a recommended cipher by the EU NESSIE (New European Schemes for Signatures, Integrity and Encryption) project and included in Japan's CRYPTREC list of approved cryptographic techniques. The cipher is also specified in the TV-Anytime Forum standards for broadcast media protection.
A Japanese company invented a fast, safe secret code called Camellia. Experts all over the world checked it and said it was good. This RFC says TLS can use it.
§2Camellia Algorithm Properties
Camellia offers significant advantages for cryptographic applications. It maintains a 128-bit block size, the same as AES, and provides three key lengths: 128 bits, 192 bits, and 256 bits. RFC 4132 defines cipher suites for both 128-bit and 256-bit keys, treating these as the most practical and efficient options for the widest range of applications.
A distinguishing feature of Camellia is its suitability for both software and hardware implementations with low power consumption. Compared to AES, Camellia offers at least comparable encryption speed in both software and hardware, while maintaining a particularly small hardware design footprint. This makes it ideal for deployment on everything from low-cost smart cards to high-speed network systems.
Camellia works just like AES, the most popular code. But it was designed to be extra small and fast on computer chips, especially ones that don't use much power.
§3New Cipher Suite Definitions
RFC 4132 defines 12 new cipher suites using Camellia in cipher block chaining (CBC) mode, combined with SHA-1 for message authentication. These suites vary by key exchange method and key size. For 128-bit Camellia keys, the cipher suites are: TLS_RSA_WITH_CAMELLIA_128_CBC_SHA, TLS_DH_DSS_WITH_CAMELLIA_128_CBC_SHA, TLS_DH_RSA_WITH_CAMELLIA_128_CBC_SHA, TLS_DHE_DSS_WITH_CAMELLIA_128_CBC_SHA, TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA, and TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA.
For 256-bit keys, the same set of key exchange options is available with corresponding cipher suites. Each key exchange method refers to different certificate and authentication approaches already defined in the TLS specification: RSA for direct authentication with RSA certificates, DH_DSS and DH_RSA for Diffie-Hellman key exchange with DSS or RSA certificates, DHE_DSS and DHE_RSA for ephemeral Diffie-Hellman with DSS or RSA signatures, and DH_anon for unauthenticated anonymous key exchange.
The RFC adds 12 new recipes for how to use Camellia in TLS. Each recipe picks a different way for the two computers to prove who they are and share the secret key.
- RSARSA Key Exchange — Direct authentication using RSA certificates.
- DH_DSSStatic Diffie-Hellman with DSS — Diffie-Hellman key exchange with DSS-signed certificates.
- DH_RSAStatic Diffie-Hellman with RSA — Diffie-Hellman key exchange with RSA-signed certificates.
- DHE_DSSEphemeral Diffie-Hellman with DSS — Temporary Diffie-Hellman key exchange with DSS signatures.
- DHE_RSAEphemeral Diffie-Hellman with RSA — Temporary Diffie-Hellman key exchange with RSA signatures.
- DH_anonAnonymous Diffie-Hellman — Unauthenticated key exchange; no certificates used.
§4Security Assurance
The RFC asserts that Camellia is cryptographically secure and has withstood extensive cryptanalytic evaluation in multiple open worldwide cryptographic evaluation projects, specifically CRYPTREC and NESSIE. At the time of publication, there were no known weak keys for Camellia. The new cipher suites are believed to be no less secure than the corresponding cipher suites already defined in TLS using other algorithms.
For additional security guidance beyond what applies specifically to Camellia, RFC 4132 defers to the security considerations of the existing TLS cipher suites and the AES cipher suites defined in RFC 3268. This maintains consistency with the security properties expected of well-vetted cryptographic protocols.
Camellia passed all the tests that smart people use to break codes. It has no known weak spots, so it is as safe as other codes already in TLS.