




TLS Working Group                               Hyangjin Lee(KISA)
INTERNET-DRAFT                                    Jaeho Yoon(KISA)
Document: draft-lee-tls-seed-01.txt                Jaeil Lee(KISA)
Expiration Date: July 2005                           January 2005


    Addition of SEED Ciphersuites to Transport Layer Security (TLS)

                      <draft-lee-tls-seed-01.txt>


Status of this Memo

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Abstract

   This document proposes the addition of new cipher suites to the
   Transport Layer Security (TLS) protocol to support the SEED
   encryption algorithm as a bulk cipher algorithm.

1. Introduction

   This document proposes the addition of new cipher suites to the TLS
   protocol [TLS] to support the SEED encryption algorithm as a bulk
   cipher algorithm.






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1.1. SEED

   SEED is a symmetric encryption algorithm that had been developed by
   KISA(Korea Information Security Agency) and a group of experts since
   1998. The input/output block size of SEED is 128-bit and the key
   length is also 128-bit. SEED has the 16-round Feistel structure.  A
   128-bit input is divided into two 64-bit blocks and the right 64-bit
   block is an input to the round function with a 64-bit subkey
   generated from the key scheduling.

   SEED is easily implemented in various software and hardware because
   it is designed to increase the efficiency of memory storage and the
   simplicity in generating keys without degrading the security of the
   algorithm. In particular, it can be effectively adopted to a
   computing environment with a restricted resources such as a mobile
   devices, smart cards and so on.

   SEED is a national industrial association standard [TTASSEED] and is
   widely used in South Korea for electronic commerce and financial
   services operated on wired & wireless PKI.

   The algorithm specification and object identifiers are described in
   [SEED-ID]. The SEED homepage,
   http://www.kisa.or.kr/seed/seed_eng.html, contains a wealth of
   information about SEED, including detailed specification, evaluation
   report, test vectors, and so on.

1.2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
   "RECOMMENDED", "MAY", and "OPTIONAL" in this document (in uppercase,
   as shown) are to be interpreted as described in [RFC2119].

2. Proposed Cipher Suites

   The new ciphersuites proposed here have the following definitions:

      CipherSuite TLS_RSA_WITH_SEED_CBC_SHA      = { 0x00, 0x96};
      CipherSuite TLS_DH_DSS_WITH_SEED_CBC_SHA   = { 0x00, 0x97};
      CipherSuite TLS_DH_RSA_WITH_SEED_CBC_SHA   = { 0x00, 0x98};
      CipherSuite TLS_DHE_DSS_WITH_SEED_CBC_SHA  = { 0x00, 0x99};
      CipherSuite TLS_DHE_RSA_WITH_SEED_CBC_SHA  = { 0x00, 0x9A};
      CipherSuite TLS_DH_anon_WITH_SEED_CBC_SHA  = { 0x00, 0x9B};

3. CipherSuite Definitions






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3.1. Cipher

   All the ciphersuites described here use SEED in cipher block
   chaining(CBC) mode as a bulk cipher algorithm.  SEED is a 128-bit
   block cipher with 128-bit key size.

3.2. Hash

   All the ciphersuites described here use SHA-1 [SHA-1] in an HMAC
   construction as described in section 5 of [TLS].

3.3. Key exchange

   The ciphersuites defined here differ in the type of certificate and
   key exchange method.  They use the following options:

      CipherSuite                         Key Exchange Algorithm

      TLS_RSA_WITH_SEED_CBC_SHA                    RSA
      TLS_DH_DSS_WITH_SEED_CBC_SHA                 DH_DSS
      TLS_DH_RSA_WITH_SEED_CBC_SHA                 DH_RSA
      TLS_DHE_DSS_WITH_SEED_CBC_SHA                DHE_DSS
      TLS_DHE_RSA_WITH_SEED_CBC_SHA                DHE_RSA
      TLS_DH_anon_WITH_SEED_CBC_SHA                DH_anon

   For the meanings of the terms RSA, DH_DSS, DH_RSA, DHE_DSS, DHE_RSA
   and DH_anon, please refer to sections 7.4.2 and 7.4.3 of [TLS].

4.  IANA considerations

   IANA does not currently have a registry for TLS-related numbers, so
   there are no IANA actions associated with this document.

5. Security Considerations

   It is not believed that the new ciphersuites are ever less secure
   than the corresponding older ones. No security problem has been found
   on SEED. SEED is robust against known attacks including Differential
   cryptanalysis, Linear cryptanalysis and related key attacks, etc.
   SEED has gone through wide public scrutinizing procedures.
   Especially, it has been evaluated and also considered
   cryptographically secure by trustworthy organizations such as ISO/IEC
   JTC 1/SC 27 and Japan CRYPTREC (Cryptography Research and Evaluation
   Committees) [ISOSEED][CRYPTREC]. SEED has been submitted to other
   several standardization bodies such as ISO(ISO/IEC 18033-3), IETF
   S/MIME Mail Security [SEED-SMIME] and it is under consideration.  For
   further security considerations, the reader is encouraged to read
   [SEED-EVAL].



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   For other security considerations, please refer to the security of
   the corresponding older ciphersuites described in [TLS] and [AES-
   TLS].

6. References

6.1 Normative Reference

   [RFC2119]   S. Bradner, "Key words for use in RFCs to Indicate
               Requirement Levels", BCP 14, RFC 2119, March 1997.

   [SEED]      KISA, "SEED Algorithm Specification",
               http://www.kisa.or.kr/seed/seed_eng.html"

   [TLS]       T. Dierks, and C. Allen, "The TLS Protocol Version 1.0",
            RFC 2246, January 1999.

6.2 Informative Reference

   [AES-TLS]   P. Chown, "Advanced Encryption Standard (AES)
               Ciphersuites for Transport Layer Security (TLS)",
               RFC 3268, June 2002.

   [CRYPTREC]  Information-technology Promotion Agency (IPA), Japan,
               CRYPTREC. "SEED Evaluation Report", February, 2002
               http://www.kisa.or.kr/seed/seed_eng.html

   [ISOSEED]   ISO/IEC JTC 1/SC 27, "National Body contributions on
               NP 18033 "Encryption Algorithms" in Response to SC 27
               N2563 (ATT.3 Korea Contribution)", ISO/IEC JTC 1/SC 27
               N2656r1 (n2656_3.zip), October, 2000

   [SEED-EVAL] KISA, "Self Evaluation Report",
               http://www.kisa.or.kr/seed/seed_eng.html"

   [SEED-ID]   Jongwook Park, Sungjae Lee, Jeeyeon Kim, Jaeil Lee,
               "The SEED Encryption Algorithm", draft-park-seed-01.txt,
               April, 2004.

   [SEED-SMIME] Jongwook Park, Sungjae Lee, Jeeyeon Kim, Jaeil Lee,
               "Use of the SEED Encryption Algorithm in CMS",
               draft-ietf-smime-cms-01.txt, April, 2004.

   [SHA-1]     FIPS PUB 180-1, "Secure Hash Standard", National Institute
               of Standards and Technology, U.S. Department of Commerce,
               April 17, 1995.

   [TTASSEED]  Telecommunications Technology Association (TTA),



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               South Korea, "128-bit Symmetric Block Cipher (SEED)",
               TTAS.KO-12.0004, September, 1998 (In Korean)
               http://www.tta.or.kr/English/new/main/index.htm

7. Authorsí¯ Addresses

     Hyangjin Lee
     Korea Information Security Agency
     Phone: +82-2-405-5446
     FAX  : +82-2-405-5499
     Email: jiinii@kisa.or.kr

     Jaeho Yoon
     Korea Information Security Agency
     Phone: +82-2-405-5434
     FAX  : +82-2-405-5499
     Email: jhyoon@kisa.or.kr

     Jaeil Lee
     Korea Information Security Agency
     Phone: +82-2-405-5300
     FAX  : +82-2-405-5499
     Email: jilee@kisa.or.kr


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