Camellia TLS: Camellia Cipher Suites for TLS
TLS cipher suites that use the Camellia block cipher, now with SHA-256 variants alongside the SHA-1 ones.
Kato, A., Kanda, M., and S. Kanno, "Camellia Cipher Suites for TLS", RFC 5932, DOI 10.17487/RFC5932, June 2010, <https://www.rfc-editor.org/info/rfc5932>.
@misc{rfc5932,
series = {Request for Comments},
number = 5932,
howpublished = {RFC 5932},
publisher = {RFC Editor},
doi = {10.17487/RFC5932},
url = {https://www.rfc-editor.org/info/rfc5932},
author = {A. Kato and M. Kanda and S. Kanno},
title = {{Camellia Cipher Suites for TLS}},
pagetotal = 6,
year = 2010,
month = jun,
} RFC text
Contents
Internet Engineering Task Force (IETF) A. Kato
Request for Comments: 5932 NTT Software Corporation
Obsoletes: 4132 M. Kanda
Category: Standards Track NTT
ISSN: 2070-1721 S. Kanno
NTT Software Corporation
June 2010
Camellia Cipher Suites for TLS
Abstract
This document specifies a set of cipher suites for the Transport
Security Layer (TLS) protocol to support the Camellia encryption
algorithm as a block cipher. It amends the cipher suites originally
specified in RFC 4132 by introducing counterparts using the newer
cryptographic hash algorithms from the SHA-2 family. This document
obsoletes RFC 4132.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5932.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
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than English.
1. Introduction
This document proposes the addition of new cipher suites to the
Transport Layer Security (TLS) [RFC5246] protocol to support the
Camellia [RFC3713] encryption algorithm as a block cipher algorithm,
adding variants using the SHA-2 family of cryptographic hash
algorithms [FIPS180-3] to the TLS cipher suite portfolio originally
specified in RFC 4132 [RFC4132]. This document obsoletes RFC 4132.
The Camellia algorithm and its properties are described in [RFC3713].
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2. Proposed Cipher Suites
The cipher suites defined here have the following identifiers:
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 };
CipherSuite TLS_RSA_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBA };
CipherSuite TLS_DH_DSS_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBB };
CipherSuite TLS_DH_RSA_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBC };
CipherSuite TLS_DHE_DSS_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBD };
CipherSuite TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBE };
CipherSuite TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBF };
CipherSuite TLS_RSA_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC0 };
CipherSuite TLS_DH_DSS_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC1 };
CipherSuite TLS_DH_RSA_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC2 };
CipherSuite TLS_DHE_DSS_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC3 };
CipherSuite TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC4 };
CipherSuite TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC5 };
3. Cipher Suite Definitions
3.1. Key Exchange
The RSA, DHE_RSA, DH_RSA, DHE_DSS, DH_DSS, and DH_anon key exchanges
are performed as defined in [RFC5246].
3.2. Cipher
The CAMELLIA_128_CBC cipher suites use Camellia [RFC3713] in Cipher
Block Chaining (CBC) mode with a 128-bit key and 128-bit IV; the
CAMELLIA_256_CBC cipher suites use a 256-bit key and 128-bit IV.
3.3. Hash and Pseudorandom Function
3.3.1. Hash and Pseudorandom Function for TLS 1.1
The cipher suites ending with _SHA use HMAC-SHA1 as the MAC
algorithm.
When used with TLS versions prior to 1.2, the pseudorandom function
(PRF) is calculated as specified in the appropriate version of the
TLS specification.
3.3.2. Hash and Pseudorandom Function for TLS 1.2
The cipher suites ending with _SHA256 use HMAC-SHA-256 as the MAC
algorithm. The PRF is the TLS PRF [RFC5246] with SHA-256 as the hash
function. These cipher suites MUST NOT be negotiated by TLS 1.1 or
earlier versions. Clients MUST NOT offer these cipher suites if they
do not offer TLS 1.2 or later. Servers that select an earlier
version of TLS MUST NOT select one of these cipher suites.
4. IANA Considerations
IANA has updated the entries for the following numbers that were
allocated in RFC 4132 to reference this document:
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 };
IANA has allocated the following numbers in the TLS Cipher Suite
Registry:
CipherSuite TLS_RSA_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBA };
CipherSuite TLS_DH_DSS_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBB };
CipherSuite TLS_DH_RSA_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBC };
CipherSuite TLS_DHE_DSS_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBD };
CipherSuite TLS_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBE };
CipherSuite TLS_DH_anon_WITH_CAMELLIA_128_CBC_SHA256 = { 0x00,0xBF };
CipherSuite TLS_RSA_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC0 };
CipherSuite TLS_DH_DSS_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC1 };
CipherSuite TLS_DH_RSA_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC2 };
CipherSuite TLS_DHE_DSS_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC3 };
CipherSuite TLS_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC4 };
CipherSuite TLS_DH_anon_WITH_CAMELLIA_256_CBC_SHA256 = { 0x00,0xC5 };
5. 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]).
Also, security issues are discussed throughout RFC 5246 [RFC5246],
especially in Appendices D, E, and F.
6. References
6.1. Normative References
[FIPS180-3] National Institute of Standards and Technology, "Secure
Hash Standard (SHS)", FIPS PUB 180, October 2008,
<http://csrc.nist.gov/publications/fips/fips180-3/
fips180-3_final.pdf>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3713] Matsui, M., Nakajima, J., and S. Moriai, "A Description
of the Camellia Encryption Algorithm", RFC 3713,
April 2004.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer
Security (TLS) Protocol Version 1.2", RFC 5246,
August 2008.
6.2. Informative References
[CRYPTREC] Information-technology Promotion Agency (IPA),
"Cryptography Research and Evaluation Committees",
<http://www.ipa.go.jp/security/enc/CRYPTREC/
index-e.html>.
[LNCS] Mala, H., Shakiba, M., and M. Dakhil-alian, "New Results
on Impossible Differential Cryptanalysis of Reduced
Round Camellia-128", LNCS 5867, November 2009,
<http://www.springerlink.com/content/e55783u422436g77/>.
[NESSIE] "The NESSIE project (New European Schemes for
Signatures, Integrity and Encryption)",
<http://www.cosic.esat.kuleuven.be/nessie/>.
[RFC4132] Moriai, S., Kato, A., and M. Kanda, "Addition of
Camellia Cipher Suites to Transport Layer Security
(TLS)", RFC 4132, July 2005.
Authors' Addresses
Akihiro Kato
NTT Software Corporation
Phone: +81-45-212-9803
Fax: +81-45-212-9800
EMail: kato.akihiro@po.ntts.co.jp
Masayuki Kanda
NTT
Phone: +81-422-59-3456
Fax: +81-422-59-4015
EMail: kanda.masayuki@lab.ntt.co.jp
Satoru Kanno
NTT Software Corporation
Phone: +81-45-212-9803
Fax: +81-45-212-9800
EMail: kanno.satoru@po.ntts.co.jp
AI ELI5
On this page
§1Introduction
RFC 5932 adds cipher suites to the Transport Layer Security protocol (TLS 1.2, RFC 5246) so that it can use the Camellia block cipher, which RFC 3713 describes. It builds on the suites originally specified in RFC 4132 by adding variants that use the SHA-2 family of hash algorithms.
The document obsoletes RFC 4132. It contains no new protocol machinery: it assigns names and numbers to cipher suites and says how each part of a suite is to be computed.
TLS keeps a menu of ways to scramble messages. This document adds more Camellia dishes to the menu.
§2The Cipher Suites
There are 24 suites in four groups of six. Each group has one entry for each key exchange: RSA, DH_DSS, DH_RSA, DHE_DSS, DHE_RSA and DH_anon. The groups are Camellia with a 128-bit key and SHA, Camellia with a 256-bit key and SHA, and the same two with SHA256.
Each suite has a two-byte identifier. For example, TLS_RSA_WITH_CAMELLIA_128_CBC_SHA is { 0x00,0x41 } and TLS_RSA_WITH_CAMELLIA_128_CBC_SHA256 is { 0x00,0xBA }. The 128-bit SHA group runs from 0x41 to 0x46, the 256-bit SHA group from 0x84 to 0x89, the 128-bit SHA256 group from 0xBA to 0xBF and the 256-bit SHA256 group from 0xC0 to 0xC5.
Each cipher suite is a combo meal with a code number: which way to swap secrets, which scrambler, and which seal to check the message.
| Group | Key size | MAC | Identifiers |
|---|---|---|---|
| CAMELLIA_128_CBC_SHA | 128 bits | HMAC-SHA1 | 0x41 to 0x46 |
| CAMELLIA_256_CBC_SHA | 256 bits | HMAC-SHA1 | 0x84 to 0x89 |
| CAMELLIA_128_CBC_SHA256 THIS RFC | 128 bits | HMAC-SHA-256 | 0xBA to 0xBF |
| CAMELLIA_256_CBC_SHA256 THIS RFC | 256 bits | HMAC-SHA-256 | 0xC0 to 0xC5 |
§3How the Suites Are Built
The key exchanges (RSA, DHE_RSA, DH_RSA, DHE_DSS, DH_DSS and DH_anon) work exactly as RFC 5246 defines them. The cipher is Camellia in Cipher Block Chaining (CBC) mode. The CAMELLIA_128_CBC suites use a 128-bit key and a 128-bit IV, and the CAMELLIA_256_CBC suites use a 256-bit key and a 128-bit IV.
Suites ending in _SHA use HMAC-SHA1 as the MAC algorithm. With TLS versions before 1.2, the pseudorandom function (PRF) is computed as that version of TLS specifies.
Suites ending in _SHA256 use HMAC-SHA-256 as the MAC, and the PRF is the TLS PRF from RFC 5246 with SHA-256 as the hash. Because of this, they MUST NOT be negotiated by TLS 1.1 or earlier. A client MUST NOT offer them unless it also offers TLS 1.2 or later, and a server that selects an earlier version MUST NOT select one of them.
The scrambler uses a secret key. The SHA seal is like wax on an envelope, and the newer SHA-256 wax is only allowed with the newest version of TLS.
§4IANA Registrations
IANA updated the registry entries for the twelve SHA suites that RFC 4132 had allocated (0x41 to 0x46 and 0x84 to 0x89) so that they reference this document instead. It also allocated twelve new numbers in the TLS Cipher Suite Registry for the SHA256 suites (0xBA to 0xBF and 0xC0 to 0xC5).
A librarian keeps the official list of code numbers. The old numbers now point to this document, and twelve new numbers were added.
§5Security Considerations
The RFC says that when it was written there were no known weak keys for Camellia and no security problem had been found in it, citing the NESSIE project, CRYPTREC and a paper on impossible differential cryptanalysis of reduced-round Camellia-128. That is a statement about the time of writing, not a lasting guarantee.
It also points to the security discussion throughout RFC 5246, especially its Appendices D, E and F. It adds no other security analysis of its own.
When this was written, nobody had found a way to break Camellia. It also tells readers to look at the TLS rules for more safety advice.