Network Working Group D. Shaw Updates: 4880 (if approved) Intended status: Standards Track Expires: October
16,27, 2008 The Camellia Cipher in OpenPGP draft-ietf-openpgp-camellia-02draft-ietf-openpgp-camellia-03 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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 16,27, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract This document presents the necessary information to use the Camellia symmetric block cipher in the OpenPGP protocol. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements notation . . . . . . . . . . . . . . . . . . . . . 3 3. Camellia . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 6. Normative References . . . . . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 4 Intellectual Property and Copyright Statements . . . . . . . . . . 5 1. Introduction The OpenPGP protocol [RFC4880] can support many different symmetric ciphers. This document presents the necessary information to use the Camellia [RFC3713] cipher in the OpenPGP protocol. 2. Requirements notation 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 block cipher (as isare AES and Twofish in 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 | XXXX | | 192 | YYYY | | 256 | ZZZZ | +---------------------+----------------------------------------+ [[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 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 symmetric-only encrypted messages, as this OpenPGP message type does not perform cipher negotiation. Those using optional ciphers in this manner should take care they are using a cipher that their intended recipient can decrypt. 4. 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 current literature, as well as the Camellia home page at <http://info.isl.ntt.co.jp/camellia/>, to determine if Camellia has been found to be vulnerable to attack. 5. IANA Considerations This document requires IANA to assign twothree 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 Shaw Email: firstname.lastname@example.org 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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