Addition of SEED Cipher Suites to Transport Layer Security (TLS)
RFC 4162

Document Type RFC - Proposed Standard (September 2005; No errata)
Was draft-lee-tls-seed (individual in sec area)
Authors Jaeho Yoon  , Jaeil Lee  , Hyangjin Lee 
Last updated 2013-03-02
Stream IETF
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IESG IESG state RFC 4162 (Proposed Standard)
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Responsible AD Russ Housley
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Network Working Group                                           H.J. Lee
Request for Comments: 4162                                     J.H. Yoon
Category: Standards Track                                       J.I. Lee
                                                             August 2005

    Addition of SEED Cipher Suites to Transport Layer Security (TLS)

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).


   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.

1.1.  SEED

   SEED is a symmetric encryption algorithm that was developed by Korea
   Information Security Agency (KISA) and a group of experts, beginning
   in 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.

Lee, et al.                 Standards Track                     [Page 1]
RFC 4162               SEED Cipher Suites to TLS             August 2005

   SEED is easily implemented in various software and hardware because
   it is designed to increase the efficiency of memory storage and the
   simplicity of generating keys without degrading the security of the
   algorithm.  In particular, it can be effectively adopted in a
   computing environment that has a restricted resources such as 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-ALG].  The SEED homepage,, 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 cipher suites 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.  Cipher Suite Definitions

3.1.  Cipher

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

Lee, et al.                 Standards Track                     [Page 2]
RFC 4162               SEED Cipher Suites to TLS             August 2005

3.3.  Key Exchange

   The cipher suites 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.  Security Considerations

   It is not believed that the new cipher suites are 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.
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