Network Working Group S. Kanno Internet-Draft NTT Software Corporation Intended status: Standards Track M. Kanda Expires: October 8, 2009 Nippon Telegraph and Telephone Corporation April 6, 2009 The Camellia Algorithm and Its Use wiht the Secure Real-time Transport Protocol(SRTP) draft-avt-kanno-srtp-camellia-00 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. 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 obsoleted 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-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on October 8, 2009. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Kanno & Kanda Expires October 8, 2009 [Page 1] Internet-Draft Camellia Algorithm Suites for SRTP April 2009 Abstract This document describes the use of the Camellia block cipher algorithm in the Secure Real-time Transport Protocol (SRTP) for providing confidentiality for the Real-time Transport Protocol (RTP) traffic and for the control traffic for RTP, the Real-time Transport Control Protocol (RTCP). 1. Introduction This document describes the use of the Camellia [RFC3713] block cipher algorithm in the Secure Real-time Transport Protocol (SRTP) [RFC3711] for providing confidentiality for the Real-time Transport Protocol (RTP) [RFC3550] traffic and for the control traffic for RTP, the Real-time Transport Control Protocol (RTCP) [RFC3550]. 1.1. Camellia Camellia is a symmetric cipher with a Feistel structure. Camellia was developed jointly by NTT and Mitsubishi Electric Corporation in 2000. It was designed to withstand all known cryptanalytic attacks, and it has been scrutinized by worldwide cryptographic experts. Camellia is suitable for implementation in software and hardware, offering encryption speed in software and hardware implementations that is comparable to Advanced Encryption Standard (AES) [FIPS.197.2001]. Camellia supports 128-bit block size and 128-, 192-, and 256-bit key lengths, i.e., the same interface specifications as the AES. Therefore, it is easy to implement Camellia based algorithms by replacing the AES block of AES based algorithms with a Camellia block. Camellia already has been adopted by the IETF and other international standardization organizations; in particular, the IETF has published specifications for the use of Camellia with IPsec [RFC4312], TLS [RFC4132], S/MIME [RFC3657] and XML Security [RFC4051]. Camellia is one of the three ISO/IEC international standard [ISO/IEC 18033-3] 128-bit block ciphers (Camellia, AES, and SEED). Camellia was selected as a recommended cryptographic primitive by the EU NESSIE (New European Schemes for Signatures, Integrity and Encryption) project [NESSIE] and was included in the list of cryptographic techniques for Japanese e-Government systems that was selected by the Japanese CRYPTREC (Cryptography Research and Evaluation Committees) [CRYPTREC]. Since optimized source code is provided under several open source Kanno & Kanda Expires October 8, 2009 [Page 2] Internet-Draft Camellia Algorithm Suites for SRTP April 2009 licenses [open source license], Camellia is also adopted by several open source projects (OpenSSL, GnuTLS, FreeBSD, and Linux). Camellia is also adopted by Mozilla and Camellia is ready for use with Firefox 3.0 released in June 2008. The algorithm specification and object identifiers are described in [RFC3713]. The Camellia web site [Camellia web site] contains a wealth of information about Camellia, including detailed specification, security analysis, performance figures, reference implementation, optimized implementation, test vectors(TV), and intellectual property information. 1.2. Terminology 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 [RFC2119]. 2. Camellia Algorithm Suites for SRTP All symmetric block cipher algorithms share common characteristics and valuables, including mode, key size, weak keys, and block size. Camellia algorithm is specified as well as AES, those relations are following: a) Camellia-CTR comply with [RFC3711] b) Camellia-GCM/CCM comply with [AES-GCM/CCM] 3. Default and mandatory-to-implement Transforms The default transforms also are mandatory-to-implement transforms in SRTP. Of course, "mandatory-to-implement" does not imply "mandatory- to-use". Table 1 summarizes the pre-defined transforms. The default values below are valid for the pre-defined transforms. man.-to-impl. optional default encryption Camellia-CTR Camellia-CCM, -GCM Camellia-CTR message integrity HMAC-SHA1 Camellia-CCM, -GCM HMAC-SHA1 key derivation (PRF) Camellia-CTR - Camellia-CTR Table 1: Mandatory-to-implement, optional and default transforms in SRTP and SRTCP. Kanno & Kanda Expires October 8, 2009 [Page 3] Internet-Draft Camellia Algorithm Suites for SRTP April 2009 4. Security Considerations At the time of writing this document, there are no known weak keys for Camellia. Also, No security problem has been found on Camellia. Camellia is secure against all known attacks including Differential cryptanalysis, linear cryptanalysis, and related key attacks. The security considerations in RFC 5289 [RFC3711] and Draft of AES- GCM and AES-CCM for SRTP [AES-GCM/CCM] apply to this document as well. 5. IANA Considerations RFC 4568 [RFC4568] defines SRTP "crypto suites"; also, [AES-GCM/CCM] defines a crypto suite corresponds to a particular AEAD algorithm in SRTP. In order to allow SDP to signal the use of the algorithms defined in this document, IANA will register the following crypto suites into the subregistry for SRTP crypto suites under the SRTP transport of the SDP Security Descriptions: srtp-crypto-suite-ext = "CAMELLIA_CM_128_HMAC_SHA1_80" / "CAMELLIA_CM_128_HMAC_SHA1_32" / "AEAD_CAMELLIA_128_GCM" / "AEAD_CAMELLIA_256_GCM" / "AEAD_CAMELLIA_128_GCM_8" / "AEAD_CAMELLIA_256_GCM_8" / "AEAD_CAMELLIA_128_GCM_12" / "AEAD_CAMELLIA_256_GCM_12" / "AEAD_CAMELLIA_128_CCM" / "AEAD_CAMELLIA_256_CCM" / srtp-crypto-suite-ext 6. Test Vectors TBD. 7. References 7.1. Normative References [AES-GCM/CCM] McGrew, D., "AES-GCM and AES-CCM Authenticated Encryption in Secure RTP (SRTP)", draft-mcgrew-srtp-aes-gcm-00 (work in progress), October 2008. Kanno & Kanda Expires October 8, 2009 [Page 4] Internet-Draft Camellia Algorithm Suites for SRTP April 2009 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, July 2003. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, March 2004. [RFC3713] Matsui, M., Nakajima, J., and S. Moriai, "A Description of the Camellia Encryption Algorithm", RFC 3713, April 2004. [RFC4568] Andreasen, F., Baugher, M., and D. Wing, "Session Description Protocol (SDP) Security Descriptions for Media Streams", RFC 4568, July 2006. 7.2. Informative References [CRYPTREC] Information-technology Promotion Agency (IPA), "Cryptography Research and Evaluation Committees", . [Camellia web site] "Camellia web site", . [FIPS.197.2001] National Institute of Standards and Technology, "Advanced Encryption Standard (AES)", FIPS PUB 197, November 2001, < http://csrc.nist.gov/publications/fips/fips197/ fips-197.pdf>. [ISO/IEC 18033-3] International Organization for Standardization, "Information technology - Security techniques - Encryption algorithms - Part 3: Block ciphers", ISO/IEC 18033-3, July 2005. [NESSIE] "The NESSIE project (New European Schemes for Signatures, Integrity and Encryption)", . [RFC3657] Moriai, S. and A. Kato, "Use of the Camellia Encryption Algorithm in Cryptographic Message Syntax (CMS)", RFC 3657, January 2004. Kanno & Kanda Expires October 8, 2009 [Page 5] Internet-Draft Camellia Algorithm Suites for SRTP April 2009 [RFC4051] Eastlake, D., "Additional XML Security Uniform Resource Identifiers (URIs)", RFC 4051, April 2005. [RFC4132] Moriai, S., Kato, A., and M. Kanda, "Addition of Camellia Cipher Suites to Transport Layer Security (TLS)", RFC 4132, July 2005. [RFC4312] Kato, A., Moriai, S., and M. Kanda, "The Camellia Cipher Algorithm and Its Use With IPsec", RFC 4312, December 2005. [open source license] "Camellia open source software", . Authors' Addresses Satoru Kanno NTT Software Corporation Phone: +81-45-212-7577 Fax: +81-45-212-9800 Email: kanno-s@po.ntts.co.jp Masayuki Kanda Nippon Telegraph and Telephone Corporation Phone: +81-422-59-3456 Fax: +81-422-59-4015 Email: kanda.masayuki@lab.ntt.co.jp Kanno & Kanda Expires October 8, 2009 [Page 6]