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
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Kato, et al. Standards Track [Page 1]
RFC 5932 Camellia Cipher Suites for TLS June 2010
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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].
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].
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.
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.
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.
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.
[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/>.