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Network Working Group D. ShawInternet-Draft December 5, 2008 Updates: 4880 (if approved) Intended status: Standards Track Expires:Request for Comments: 5581 June8,2009 Updates: 4880 Category: Informational The Camellia Cipher in OpenPGPdraft-ietf-openpgp-camellia-04Status ofthisThis MemoBy submitting this Internet-Draft, each author represents thatThis memo provides information for the Internet community. It does not specify an Internet standard of anyapplicable patent or other IPR claimskind. Distribution ofwhich he or shethis memo isaware have been or will be disclosed,unlimited. Copyright Notice Copyright (c) 2009 IETF Trust andany of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents oftheInternet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documentspersons identified asInternet- Drafts. 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Abstract This document presents the necessary information to use the Camellia symmetric block cipher in the OpenPGP protocol.Shaw Expires June 8, 2009 [Page 1] Internet-Draft The Camellia Cipher in OpenPGP December 2008Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . .32 2. RequirementsnotationNotation . . . . . . . . . . . . . . . . . . . . .32 3. Camellia . . . . . . . . . . . . . . . . . . . . . . . . . . .32 4. Security Considerations . . . . . . . . . . . . . . . . . . . .42 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . .43 6. Normative References . . . . . . . . . . . . . . . . . . . . .4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 4 Intellectual Property and Copyright Statements . . . . . . . . . . 53 ShawExpires June 8, 2009Informational [Page2] Internet-Draft1] RFC 5581 The Camellia Cipher in OpenPGPDecember 2008June 2009 1. Introduction The OpenPGP protocol [RFC4880] can support many different symmetric ciphers. This document presents the necessary information to use the Camellia [RFC3713] symmetric cipher in the OpenPGP protocol. 2. RequirementsnotationNotation 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]. 3. Camellia Camellia is specified in [RFC3713]. It is a 128-bit symmetric block cipher (as are AES and Twofish inOpenPGP),OpenPGP) that supports 128-bit, 192-bit, and 256-bit keys. This document defines the use of Camellia in OpenPGP. +---------------------+----------------------------------------+ | Camellia Key Length | OpenPGP Symmetric-Key Algorithm Number | +---------------------+----------------------------------------+ | 128 |XXXX11 | | 192 |YYYY12 | | 256 |ZZZZ13 | +---------------------+----------------------------------------+[[To be allocated by IANA. Please fill this in: presumably XXXX == 11, YYYY == 12, and ZZZZ == 13]]OpenPGP applications MAY implement Camellia. If implemented, Camellia may be used in any place in OpenPGP where a symmetric cipher is usable, and it is subject to the same usage requirements (such as its presence in the Preferred Symmetric Algorithms signature subpacket) as the other symmetric ciphers in OpenPGP. While the OpenPGP algorithm preferences system prevents interoperability problems with public key encrypted messages, if Camellia (or any other optional cipher) is used for encrypting private keys, there could be interoperability problems when migrating a private key from one system to another. A similar issue can arise when using an optional cipher for symmetrically encrypted messages, as this OpenPGP message type does notperform cipher negotiation.use the algorithm preferences system. Those using optional ciphers in this manner should take care they are using a cipher that their intended recipient can decrypt.Shaw Expires June 8, 2009 [Page 3] Internet-Draft The Camellia Cipher in OpenPGP December 20084. Security Considerations At publication time, there are no known weak keys for Camellia, and the Camellia algorithm is believed to be strong. However, as with any technology involving cryptography, implementers should check the Shaw Informational [Page 2] RFC 5581 The Camellia Cipher in OpenPGP June 2009 current literature, as well as the Camellia home page at<http://info.isl.ntt.co.jp/camellia/>,http://info.isl.ntt.co.jp/camellia/ to determine if Camellia has been found to be vulnerable to attack. 5. IANA ConsiderationsThis document requiresIANAto assignassigned three algorithm numbers from the registry of OpenPGP Symmetric-Key Algorithms that was created by [RFC4880]. 6. Normative References [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. [RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. Thayer, "OpenPGP Message Format", RFC 4880, November 2007. Author's Address David ShawEmail:EMail: dshaw@jabberwocky.com ShawExpires June 8, 2009Informational [Page4] Internet-Draft The Camellia Cipher in OpenPGP December 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Shaw Expires June 8, 2009 [Page 5]3] ----