rfc3058.txt

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RFC 3058            IDEA Encryption Algorithm in CMS       February 2001


   in the key encipherment algorithms portion of the SMIMECapabilities
   list.  The SMIMECapability SEQUENCE representing IDEA key wrapping
   MUST be DER-encoded as follows: 300D 060B 2B06 0104 0181 3C07 0101
   06.

   The ASN.1 notation of the SMIMECapability SEQUENCE representing IDEA
   is

      SMIMECapability ::= SEQUENCE {
         capabilityID OBJECT IDENTIFIER,
         parameters ANY DEFINED BY capabilityID OPTIONAL }

   where capabilityID is IDEA-CBC (no parameters) for IDEA content
   encryption in CBC mode or capabilityID is id-alg-CMSIDEAwrap (no
   parameters) for IDEA key wrapping.

5. Activation of IDEA in S/MIME Clients

   When a sending agent creates an encrypted message, it has to decide
   which type of encryption algorithm to use.  In general the decision
   process involves information obtained from the capabilities lists
   included in messages received from the recipient, as well as other
   information such as private agreements, user preferences, legal
   restrictions, etc.  If users require IDEA for symmetric encryption,
   it must be supported by the S/MIME clients on both the sending and
   receiving side, and it must be set in the user preferences.

A. References

   [IDEA]       X. Lai, "On the design and security of block ciphers",
                ETH Series in Information Processing, J.L. Massey
                (editor), vol. 1, Hartung-Gorre Verlag Konstanz,
                Technische Hochschule (Zurich), 1992.  A. J. Menezes,
                P.C. v. Oorschot, S.A. Vanstone, "Handbook of Applied
                Cryptography," CRC Press New York, 1997, p. 265.  B.
                Schneier, "Applied Cryptography," 2nd ed., John Wiley &
                Sons Inc.  New York, 1996, pp. 319-325. IPR: see the
                "IETF Page of Intellectual Property Rights Notices",
                http://www.ietf.org/ipr.html

   [SMIME2]     Dusse, S., Hoffman, P., Ramsdell, B., Lundblade, l. and
                L. Repka, "S/MIME Version 2 Message Specification", RFC
                2311, March 1998.

   [SMIME2]     Dusse, S., Hoffman, P., Ramsdell, B. and J. Weinstein,
                "S/MIME Version 2 Certificate Handling", RFC 2312, March
                1998.




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RFC 3058            IDEA Encryption Algorithm in CMS       February 2001


   [SMIME3]     Dusse, S., Hoffman, P., Ramsdell, B. and J. Weinstein,
                "S/MIME Version 3 Certificate Handling", RFC 2632, March
                1998.

   [SMIME3]     Ramsdell, B., "S/MIME Version 3 Message Specification",
                RFC 2633, June 1999.

   [MUSTSHOULD] Bradner, S.,"Key words for use in RFCs to Indicate
                Requirement Levels", BCP 14, RFC 2119, March 1997.

   [CMS]        Housley, R., "Cryptographic Message Syntax", RFC 2630,
                June 1999.

   [PKCS7]      Kaliski, B., "PKCS #7: Cryptographic Message Syntax
                Version 1.5", RFC 2315, March 1998.

B. Comments on IDEA Security and Standards

   The IDEA algorithm was developed in a joint project involving the
   Swiss Federal Institute of Technology in Zurich (Dr. X. Lai and Prof.
   J.L. Massey) and Ascom Ltd.  The aim of the project was to develop a
   strong encryption algorithm that could replace the DES algorithm.

   IDEA uses 128-bit secret keys and encrypts one 64-bit block at a time
   [IDEA].  It was particularly strengthened to protect against
   differential cryptoanalysis attacks.  For the full 8-round IDEA there
   is no attack known which is better than exhaustive search on the
   total 128-bit key space.

   IDEA permits the implementation of standard Electronic Data
   Interchange applications.  It has been entered in the ISO/IEC
   register for encryption algorithms and incorporated in the "SECURITY
   GUIDE LINES" code list by the UNI/EDIFACT "SECURITY JOINT WORKING
   GROUP".

C. Intellectual Property Rights Notice

   Ascom Ltd. holds the patent to IDEA.  In accordance with the
   intellectual property rights procedures of the IETF standards
   process, Ascom offers a non-exclusive license under reasonable and
   non-discriminatory terms and conditions.

   IDEA(TM) is protected by international copyright law and in addition
   has been patented in several countries.  Because Ascom wants to make
   this highly secure algorithm widely available, the non-commercial use
   of this algorithm is free.





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RFC 3058            IDEA Encryption Algorithm in CMS       February 2001


   Any party wishing to know more about IDEA or to request a license
   should visit the web sites <http://www.media-crypt.com/>,
   <http://www.it-sec.com/> or send an e-mail to [e-mail] or
   [e-mail].

D. Acknowledgements

   We would like to thank Russ Housley, Jim Schaad and Francois Zeller
   for their contributions to this document.

E. Authors' Addresses

   Stephan Teiwes
   iT_Security AG (Ltd.)
   Badenerstrasse 530
   CH-8048 Zurich, Switzerland

   Phone: [phone]
   Fax  : [phone]
   EMail: [e-mail]


   Peter Hartmann
   iT_Security AG (Ltd.)
   Badenerstrasse 530
   CH-8048 Zurich, Switzerland

   Phone: [phone]
   Fax  : [phone]
   EMail: [e-mail]


   Diego Kuenzi
   724 Solutions Inc.
   Bahnhofstrasse 16
   CH-5600 Lenzburg, Switzerland

   Phone: [phone]
   Fax:   [phone]
   EMail: [e-mail]











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RFC 3058            IDEA Encryption Algorithm in CMS       February 2001


F.  Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.

   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.

   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS 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.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















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