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RFC 6209 INFORMATIONAL TLS · CIPHERS · ENCRYPTION

ARIA TLS: Addition of the ARIA Cipher Suites to Transport Layer Security (TLS)

Registers 54 TLS cipher suites that use the Korean ARIA block cipher, with SHA-2 hashes, GCM and pre-shared keys.

On rfc-editor.org ↗
PUBLISHED
April 2011
AUTHORS
W. Kim, J. Lee, J. Park, D. Kwon
STREAM
IETF
UPDATED BY
RFC 10015 — Deprecate TLS 1.2 kex
KEY SIZES
128, 192 and 256 bits
BLOCK SIZE
128 bits
ROUNDS
12, 14 or 16, depending on key size
CODE POINT RANGE
0xC0,0x3C to 0xC0,0x71
HASHES USED
SHA-256 and SHA-384
DOI
10.17487/RFC6209

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗ 
Internet Engineering Task Force (IETF)                            W. Kim
Request for Comments: 6209                                        J. Lee
Category: Informational                                          J. Park
ISSN: 2070-1721                                                  D. Kwon
                                                                    NSRI
                                                              April 2011


  Addition of the ARIA Cipher Suites to Transport Layer Security (TLS)

Abstract

   This document specifies a set of cipher suites for the Transport
   Layer Security (TLS) protocol to support the ARIA encryption
   algorithm as a block cipher.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6209.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 2
     1.1.  ARIA  . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Proposed Cipher Suites  . . . . . . . . . . . . . . . . . . . . 3
     2.1.  HMAC-Based Cipher Suites  . . . . . . . . . . . . . . . . . 3
     2.2.  GCM-Based Cipher Suites . . . . . . . . . . . . . . . . . . 3
     2.3.  PSK Cipher Suites . . . . . . . . . . . . . . . . . . . . . 4
   3.  Cipher Suite Definitions  . . . . . . . . . . . . . . . . . . . 5
     3.1.  Key Exchange  . . . . . . . . . . . . . . . . . . . . . . . 5
     3.2.  Cipher  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     3.3.  PRFs  . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     3.4.  PSK Cipher Suites . . . . . . . . . . . . . . . . . . . . . 5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 8

1.  Introduction

   This document specifies cipher suites for the Transport Layer
   Security (TLS) [RFC5246] protocol to support the ARIA [RFC5794]
   encryption algorithm as a block cipher algorithm.  The cipher suites
   include variants using the SHA-2 family of cryptographic hash
   functions and ARIA Galois counter mode.  Elliptic curve cipher suites
   and pre-shared key (PSK) cipher suites are also defined.

   The cipher suites with SHA-1 are not included in this document.  Due
   to recent analytic work on SHA-1 [Wang05], the IETF is gradually
   moving away from SHA-1 and towards stronger hash algorithms.

1.1.  ARIA

   ARIA is a general-purpose block cipher algorithm developed by Korean
   cryptographers in 2003.  It is an iterated block cipher with 128-,
   192-, and 256-bit keys and encrypts 128-bit blocks in 12, 14, and 16
   rounds, depending on the key size.  It is secure and suitable for
   most software and hardware implementations on 32-bit and 8-bit
   processors.  It was established as a Korean standard block cipher
   algorithm in 2004 [ARIAKS] and has been widely used in Korea,
   especially for government-to-public services.  It was included in
   PKCS #11 in 2007 [ARIAPKCS].  The algorithm specification and object
   identifiers are described in [RFC5794].

1.2.  Terminology

   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].

2.  Proposed Cipher Suites

2.1.  HMAC-Based Cipher Suites

   The first twenty cipher suites use ARIA [RFC5794] in Cipher Block
   Chaining (CBC) mode with a SHA-2 family Hashed Message Authentication
   Code (HMAC).  Eight out of twenty use elliptic curves.

   CipherSuite TLS_RSA_WITH_ARIA_128_CBC_SHA256         = { 0xC0,0x3C };
   CipherSuite TLS_RSA_WITH_ARIA_256_CBC_SHA384         = { 0xC0,0x3D };
   CipherSuite TLS_DH_DSS_WITH_ARIA_128_CBC_SHA256      = { 0xC0,0x3E };
   CipherSuite TLS_DH_DSS_WITH_ARIA_256_CBC_SHA384      = { 0xC0,0x3F };
   CipherSuite TLS_DH_RSA_WITH_ARIA_128_CBC_SHA256      = { 0xC0,0x40 };
   CipherSuite TLS_DH_RSA_WITH_ARIA_256_CBC_SHA384      = { 0xC0,0x41 };
   CipherSuite TLS_DHE_DSS_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x42 };
   CipherSuite TLS_DHE_DSS_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x43 };
   CipherSuite TLS_DHE_RSA_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x44 };
   CipherSuite TLS_DHE_RSA_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x45 };
   CipherSuite TLS_DH_anon_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x46 };
   CipherSuite TLS_DH_anon_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x47 };

   CipherSuite TLS_ECDHE_ECDSA_WITH_ARIA_128_CBC_SHA256 = { 0xC0,0x48 };
   CipherSuite TLS_ECDHE_ECDSA_WITH_ARIA_256_CBC_SHA384 = { 0xC0,0x49 };
   CipherSuite TLS_ECDH_ECDSA_WITH_ARIA_128_CBC_SHA256  = { 0xC0,0x4A };
   CipherSuite TLS_ECDH_ECDSA_WITH_ARIA_256_CBC_SHA384  = { 0xC0,0x4B };
   CipherSuite TLS_ECDHE_RSA_WITH_ARIA_128_CBC_SHA256   = { 0xC0,0x4C };
   CipherSuite TLS_ECDHE_RSA_WITH_ARIA_256_CBC_SHA384   = { 0xC0,0x4D };
   CipherSuite TLS_ECDH_RSA_WITH_ARIA_128_CBC_SHA256    = { 0xC0,0x4E };
   CipherSuite TLS_ECDH_RSA_WITH_ARIA_256_CBC_SHA384    = { 0xC0,0x4F };

2.2.  GCM-Based Cipher Suites

   The next twenty cipher suites use the same asymmetric algorithms as
   those in the previous section but use the authenticated encryption
   modes defined in TLS 1.2 with the ARIA in Galois Counter Mode (GCM)
   [GCM].

   CipherSuite TLS_RSA_WITH_ARIA_128_GCM_SHA256         = { 0xC0,0x50 };
   CipherSuite TLS_RSA_WITH_ARIA_256_GCM_SHA384         = { 0xC0,0x51 };
   CipherSuite TLS_DHE_RSA_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x52 };
   CipherSuite TLS_DHE_RSA_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x53 };
   CipherSuite TLS_DH_RSA_WITH_ARIA_128_GCM_SHA256      = { 0xC0,0x54 };
   CipherSuite TLS_DH_RSA_WITH_ARIA_256_GCM_SHA384      = { 0xC0,0x55 };
   CipherSuite TLS_DHE_DSS_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x56 };
   CipherSuite TLS_DHE_DSS_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x57 };
   CipherSuite TLS_DH_DSS_WITH_ARIA_128_GCM_SHA256      = { 0xC0,0x58 };
   CipherSuite TLS_DH_DSS_WITH_ARIA_256_GCM_SHA384      = { 0xC0,0x59 };
   CipherSuite TLS_DH_anon_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x5A };
   CipherSuite TLS_DH_anon_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x5B };

   CipherSuite TLS_ECDHE_ECDSA_WITH_ARIA_128_GCM_SHA256 = { 0xC0,0x5C };
   CipherSuite TLS_ECDHE_ECDSA_WITH_ARIA_256_GCM_SHA384 = { 0xC0,0x5D };
   CipherSuite TLS_ECDH_ECDSA_WITH_ARIA_128_GCM_SHA256  = { 0xC0,0x5E };
   CipherSuite TLS_ECDH_ECDSA_WITH_ARIA_256_GCM_SHA384  = { 0xC0,0x5F };
   CipherSuite TLS_ECDHE_RSA_WITH_ARIA_128_GCM_SHA256   = { 0xC0,0x60 };
   CipherSuite TLS_ECDHE_RSA_WITH_ARIA_256_GCM_SHA384   = { 0xC0,0x61 };
   CipherSuite TLS_ECDH_RSA_WITH_ARIA_128_GCM_SHA256    = { 0xC0,0x62 };
   CipherSuite TLS_ECDH_RSA_WITH_ARIA_256_GCM_SHA384    = { 0xC0,0x63 };

2.3.  PSK Cipher Suites

   The next fourteen cipher suites describe PSK cipher suites.  Eight
   cipher suites use an HMAC and six cipher suites use the ARIA Galois
   Counter Mode.

   CipherSuite TLS_PSK_WITH_ARIA_128_CBC_SHA256         = { 0xC0,0x64 };
   CipherSuite TLS_PSK_WITH_ARIA_256_CBC_SHA384         = { 0xC0,0x65 };
   CipherSuite TLS_DHE_PSK_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x66 };
   CipherSuite TLS_DHE_PSK_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x67 };
   CipherSuite TLS_RSA_PSK_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x68 };
   CipherSuite TLS_RSA_PSK_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x69 };
   CipherSuite TLS_PSK_WITH_ARIA_128_GCM_SHA256         = { 0xC0,0x6A };
   CipherSuite TLS_PSK_WITH_ARIA_256_GCM_SHA384         = { 0xC0,0x6B };
   CipherSuite TLS_DHE_PSK_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x6C };
   CipherSuite TLS_DHE_PSK_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x6D };
   CipherSuite TLS_RSA_PSK_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x6E };
   CipherSuite TLS_RSA_PSK_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x6F };
   CipherSuite TLS_ECDHE_PSK_WITH_ARIA_128_CBC_SHA256   = { 0xC0,0x70 };
   CipherSuite TLS_ECDHE_PSK_WITH_ARIA_256_CBC_SHA384   = { 0xC0,0x71 };

3.  Cipher Suite Definitions

3.1.  Key Exchange

   The RSA, DHE_RSA, DH_RSA, DHE_DSS, DH_DSS, DH_anon, ECDH, and ECDHE
   key exchanges are performed as defined in [RFC5246].

3.2.  Cipher

   The ARIA_128_CBC cipher suites use ARIA [RFC5794] in CBC mode with a
   128-bit key and 128-bit Initialization Vector (IV); the ARIA_256_CBC
   cipher suites use a 256-bit key and 128-bit IV.

   AES-authenticated encryption with additional data algorithms,
   AEAD_AES_128_GCM, and AEAD_AES_256_GCM are described in [RFC5116].
   AES GCM cipher suites for TLS are described in [RFC5288].  AES and
   ARIA share common characteristics, including key sizes and block
   length.  ARIA_128_GCM and ARIA_256_GCM are defined according to those
   characteristics of AES.

3.3.  PRFs

   The pseudorandom functions (PRFs) SHALL be as follows:

   a.  For cipher suites ending with _SHA256, the PRF is the TLS PRF
       [RFC5246] using SHA-256 as the hash function.

   b.  For cipher suites ending with _SHA384, the PRF is the TLS PRF
       [RFC5246] using SHA-384 as the hash function.

3.4.  PSK Cipher Suites

   Pre-shared key cipher suites for TLS are described in [RFC4279],
   [RFC4785], [RFC5487], and [RFC5489].

4.  Security Considerations

   At the time of writing this document, no security problems have been
   found on ARIA (see [YWL]).

   The security considerations in the following RFCs apply to this
   document as well: [RFC4279] [RFC4785] [RFC5116] [RFC5288] [RFC5289]
   [RFC5487] and [GCM].

5.  IANA Considerations

   IANA has allocated the following numbers in the TLS Cipher Suite
   Registry:

   CipherSuite TLS_RSA_WITH_ARIA_128_CBC_SHA256         = { 0xC0,0x3C };
   CipherSuite TLS_RSA_WITH_ARIA_256_CBC_SHA384         = { 0xC0,0x3D };
   CipherSuite TLS_DH_DSS_WITH_ARIA_128_CBC_SHA256      = { 0xC0,0x3E };
   CipherSuite TLS_DH_DSS_WITH_ARIA_256_CBC_SHA384      = { 0xC0,0x3F };
   CipherSuite TLS_DH_RSA_WITH_ARIA_128_CBC_SHA256      = { 0xC0,0x40 };
   CipherSuite TLS_DH_RSA_WITH_ARIA_256_CBC_SHA384      = { 0xC0,0x41 };
   CipherSuite TLS_DHE_DSS_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x42 };
   CipherSuite TLS_DHE_DSS_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x43 };
   CipherSuite TLS_DHE_RSA_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x44 };
   CipherSuite TLS_DHE_RSA_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x45 };
   CipherSuite TLS_DH_anon_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x46 };
   CipherSuite TLS_DH_anon_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x47 };

   CipherSuite TLS_ECDHE_ECDSA_WITH_ARIA_128_CBC_SHA256 = { 0xC0,0x48 };
   CipherSuite TLS_ECDHE_ECDSA_WITH_ARIA_256_CBC_SHA384 = { 0xC0,0x49 };
   CipherSuite TLS_ECDH_ECDSA_WITH_ARIA_128_CBC_SHA256  = { 0xC0,0x4A };
   CipherSuite TLS_ECDH_ECDSA_WITH_ARIA_256_CBC_SHA384  = { 0xC0,0x4B };
   CipherSuite TLS_ECDHE_RSA_WITH_ARIA_128_CBC_SHA256   = { 0xC0,0x4C };
   CipherSuite TLS_ECDHE_RSA_WITH_ARIA_256_CBC_SHA384   = { 0xC0,0x4D };
   CipherSuite TLS_ECDH_RSA_WITH_ARIA_128_CBC_SHA256    = { 0xC0,0x4E };
   CipherSuite TLS_ECDH_RSA_WITH_ARIA_256_CBC_SHA384    = { 0xC0,0x4F };

   CipherSuite TLS_RSA_WITH_ARIA_128_GCM_SHA256         = { 0xC0,0x50 };
   CipherSuite TLS_RSA_WITH_ARIA_256_GCM_SHA384         = { 0xC0,0x51 };
   CipherSuite TLS_DHE_RSA_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x52 };
   CipherSuite TLS_DHE_RSA_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x53 };
   CipherSuite TLS_DH_RSA_WITH_ARIA_128_GCM_SHA256      = { 0xC0,0x54 };
   CipherSuite TLS_DH_RSA_WITH_ARIA_256_GCM_SHA384      = { 0xC0,0x55 };
   CipherSuite TLS_DHE_DSS_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x56 };
   CipherSuite TLS_DHE_DSS_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x57 };
   CipherSuite TLS_DH_DSS_WITH_ARIA_128_GCM_SHA256      = { 0xC0,0x58 };
   CipherSuite TLS_DH_DSS_WITH_ARIA_256_GCM_SHA384      = { 0xC0,0x59 };
   CipherSuite TLS_DH_anon_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x5A };
   CipherSuite TLS_DH_anon_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x5B };

   CipherSuite TLS_ECDHE_ECDSA_WITH_ARIA_128_GCM_SHA256 = { 0xC0,0x5C };
   CipherSuite TLS_ECDHE_ECDSA_WITH_ARIA_256_GCM_SHA384 = { 0xC0,0x5D };
   CipherSuite TLS_ECDH_ECDSA_WITH_ARIA_128_GCM_SHA256  = { 0xC0,0x5E };
   CipherSuite TLS_ECDH_ECDSA_WITH_ARIA_256_GCM_SHA384  = { 0xC0,0x5F };
   CipherSuite TLS_ECDHE_RSA_WITH_ARIA_128_GCM_SHA256   = { 0xC0,0x60 };
   CipherSuite TLS_ECDHE_RSA_WITH_ARIA_256_GCM_SHA384   = { 0xC0,0x61 };
   CipherSuite TLS_ECDH_RSA_WITH_ARIA_128_GCM_SHA256    = { 0xC0,0x62 };
   CipherSuite TLS_ECDH_RSA_WITH_ARIA_256_GCM_SHA384    = { 0xC0,0x63 };

   CipherSuite TLS_PSK_WITH_ARIA_128_CBC_SHA256         = { 0xC0,0x64 };
   CipherSuite TLS_PSK_WITH_ARIA_256_CBC_SHA384         = { 0xC0,0x65 };
   CipherSuite TLS_DHE_PSK_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x66 };
   CipherSuite TLS_DHE_PSK_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x67 };
   CipherSuite TLS_RSA_PSK_WITH_ARIA_128_CBC_SHA256     = { 0xC0,0x68 };
   CipherSuite TLS_RSA_PSK_WITH_ARIA_256_CBC_SHA384     = { 0xC0,0x69 };
   CipherSuite TLS_PSK_WITH_ARIA_128_GCM_SHA256         = { 0xC0,0x6A };
   CipherSuite TLS_PSK_WITH_ARIA_256_GCM_SHA384         = { 0xC0,0x6B };
   CipherSuite TLS_DHE_PSK_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x6C };
   CipherSuite TLS_DHE_PSK_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x6D };
   CipherSuite TLS_RSA_PSK_WITH_ARIA_128_GCM_SHA256     = { 0xC0,0x6E };
   CipherSuite TLS_RSA_PSK_WITH_ARIA_256_GCM_SHA384     = { 0xC0,0x6F };
   CipherSuite TLS_ECDHE_PSK_WITH_ARIA_128_CBC_SHA256   = { 0xC0,0x70 };
   CipherSuite TLS_ECDHE_PSK_WITH_ARIA_256_CBC_SHA384   = { 0xC0,0x71 };

6.  References

6.1.  Normative References

   [GCM]       Dworkin, M., "Recommendation for Block Cipher Modes of
               Operation: Galois/Counter Mode (GCM) and GMAC", NIST
               SP 800-38D, November 2007.

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

   [RFC4279]   Eronen, P. and H. Tschofenig, "Pre-Shared Key
               Ciphersuites for Transport Layer Security (TLS)",
               RFC 4279, December 2005.

   [RFC4785]   Blumenthal, U. and P. Goel, "Pre-Shared Key (PSK)
               Ciphersuites with NULL Encryption for Transport Layer
               Security (TLS)", RFC 4785, January 2007.

   [RFC5116]   McGrew, D., "An Interface and Algorithms for
               Authenticated Encryption", RFC 5116, January 2008.

   [RFC5246]   Dierks, T. and E. Rescorla, "The Transport Layer Security
               (TLS) Protocol Version 1.2", RFC 5246, August 2008.

   [RFC5288]   Salowey, J., Choudhury, A., and D. McGrew, "AES Galois
               Counter Mode (GCM) Cipher Suites for TLS", RFC 5288,
               August 2008.

   [RFC5289]   Rescorla, E., "TLS Elliptic Curve Cipher Suites with SHA-
               256/384 and AES Galois Counter Mode (GCM)", RFC 5289,
               August 2008.

   [RFC5487]   Badra, M., "Pre-Shared Key Cipher Suites for TLS with
               SHA-256/384 and AES Galois Counter Mode", RFC 5487,
               March 2009.

   [RFC5489]   Badra, M. and I. Hajjeh, "ECDHE_PSK Cipher Suites for
               Transport Layer Security (TLS)", RFC 5489, March 2009.

   [RFC5794]   Lee, J., Lee, J., Kim, J., Kwon, D., and C. Kim, "A
               Description of the ARIA Encryption Algorithm", RFC 5794,
               March 2010.

6.2.  Informative References

   [ARIAKS]    Korean Agency for Technology and Standards, "128 bit
               block encryption algorithm ARIA - Part 1: General (in
               Korean)", KS X 1213-1:2009, December 2009.

   [ARIAPKCS]  RSA Laboratories, "Additional PKCS #11 Mechanisms",
               PKCS #11 v2.20 Amendment 3 Revision 1, January 2007.

   [Wang05]    Wang, X., Yin, Y., and H. Yu, "Finding Collisions in the
               Full SHA-1", CRYPTO 2005, LNCS vol.3621, pp.17-36,
               August 2005.

   [YWL]       Li, Y., Wu, W., and L. Zhang, "Integral attacks on
               reduced-round ARIA block cipher", ISPEC 2010,
               LNCS Vol.6047, pp. 19-29, May 2010.

Authors' Addresses

   Woo-Hwan Kim
   National Security Research Institute
   P.O.Box 1, Yuseong
   Daejeon  305-350
   Korea

   EMail: whkim5@ensec.re.kr


   Jungkeun Lee
   National Security Research Institute
   P.O.Box 1, Yuseong
   Daejeon  305-350
   Korea

   EMail: jklee@ensec.re.kr


   Je-Hong Park
   National Security Research Institute
   P.O.Box 1, Yuseong
   Daejeon  305-350
   Korea

   EMail: jhpark@ensec.re.kr


   Daesung Kwon
   National Security Research Institute
   P.O.Box 1, Yuseong
   Daejeon  305-350
   Korea

   EMail: ds_kwon@ensec.re.kr

AI ELI5

On this page
PROBLEMTLS had no cipher suites for ARIA, a block cipher that is a Korean standard and has been widely used in Korea.
MECHANISMThe RFC defines cipher suites that pair ARIA with the key exchanges of TLS 1.2, using either CBC mode with a SHA-2 HMAC or Galois Counter Mode (GCM), plus pre-shared key variants.
STATUS TODAYIANA allocated the code points 0xC0,0x3C through 0xC0,0x71 in the TLS Cipher Suite Registry. The RFC is Informational and has since been updated by RFC 10015.

§1Why ARIA Needs Cipher Suites

This document specifies cipher suites for Transport Layer Security (TLS) so that the ARIA encryption algorithm can be used as a block cipher. It builds on RFC 5246 (TLS 1.2) and on the ARIA description in RFC 5794.

The suites use the SHA-2 family of hash functions and ARIA in Galois Counter Mode. Elliptic curve suites and pre-shared key (PSK) suites are also defined. Suites with SHA-1 are left out on purpose, because recent analytic work on SHA-1 led the IETF to move gradually toward stronger hash algorithms.

A cipher suite is a recipe card for how two computers will scramble their messages. This document writes new recipe cards that use the ARIA scrambler.

§1.1The ARIA Cipher

ARIA is a general-purpose block cipher developed by Korean cryptographers in 2003. It is an iterated block cipher with 128-, 192- and 256-bit keys, and it encrypts 128-bit blocks in 12, 14 or 16 rounds, depending on the key size.

The RFC says it became a Korean standard block cipher algorithm in 2004 and has been widely used in Korea, especially for government-to-public services. It was included in PKCS #11 in 2007. The algorithm itself and its object identifiers are described in RFC 5794, not here.

ARIA is a scrambling method invented in Korea. It chops a message into pieces and scrambles each piece several rounds in a row.

§2The Defined Cipher Suites

The suites come in three groups, each with 128-bit and 256-bit key variants. The first twenty use ARIA in Cipher Block Chaining (CBC) mode with a SHA-2 family HMAC; eight of those twenty use elliptic curves. The next twenty use the same asymmetric algorithms but with ARIA in Galois Counter Mode (GCM), the authenticated encryption mode defined for TLS 1.2.

The last fourteen are PSK suites: eight use an HMAC and six use ARIA GCM. Names follow the pattern TLS_RSA_WITH_ARIA_128_CBC_SHA256, where the key exchange comes first, then the cipher and key size, then the hash. The 128-bit suites end in SHA256 and the 256-bit CBC suites in SHA384.

There are three boxes of recipe cards: one with a chained scrambler, one with a scrambler that also checks nobody tampered, and one for computers that already share a secret.

THE THREE GROUPS OF ARIA CIPHER SUITES
GroupModeCode points
HMAC-based (20 suites)ARIA CBC with SHA-256 or SHA-384 HMAC0xC0,0x3C to 0xC0,0x4F
GCM-based (20 suites)ARIA Galois Counter Mode0xC0,0x50 to 0xC0,0x63
PSK (14 suites)8 with HMAC, 6 with GCM0xC0,0x64 to 0xC0,0x71

§3How the Suites Work

The RSA, DHE_RSA, DH_RSA, DHE_DSS, DH_DSS, DH_anon, ECDH and ECDHE key exchanges are performed as defined in RFC 5246. The ARIA_128_CBC suites use a 128-bit key and a 128-bit initialization vector (IV); the ARIA_256_CBC suites use a 256-bit key and a 128-bit IV.

The GCM suites are defined by analogy with AES GCM (RFC 5116, RFC 5288), because AES and ARIA share key sizes and block length. The pseudorandom function (PRF) SHALL be the TLS PRF using SHA-256 for suites ending in _SHA256, and SHA-384 for suites ending in _SHA384. PSK suites are described in RFC 4279, RFC 4785, RFC 5487 and RFC 5489.

The new recipes reuse the old handshake steps and only swap in the ARIA scrambler. Which strength of checking is used depends on the name at the end of the recipe.

§4Security Considerations

The RFC states that at the time of writing no security problems had been found on ARIA, and cites a paper on integral attacks against reduced-round ARIA. It adds that the security considerations of RFC 4279, RFC 4785, RFC 5116, RFC 5288, RFC 5289, RFC 5487 and the NIST GCM specification apply to this document as well.

When this was written, nobody had found a way to break ARIA. The older safety rules for similar recipes still apply.

§5IANA Allocations

IANA has allocated the suites in the TLS Cipher Suite Registry. The values run from { 0xC0,0x3C } (TLS_RSA_WITH_ARIA_128_CBC_SHA256) to { 0xC0,0x71 } (TLS_ECDHE_PSK_WITH_ARIA_256_CBC_SHA384), in the same order as they are listed in the document.

Each recipe card got its own number in the official list so every computer knows which card is meant.

§7References

[RFC5246]RFC 5246Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008.August 2008[RFC5794]RFC 5794Lee, J., Lee, J., Kim, J., Kwon, D., and C. Kim, "A Description of the ARIA Encryption Algorithm", RFC 5794, March 2010.March 2010[RFC5116]RFC 5116McGrew, D., "An Interface and Algorithms for Authenticated Encryption", RFC 5116, January 2008.January 2008[RFC5288]RFC 5288Salowey, J., Choudhury, A., and D. McGrew, "AES Galois Counter Mode (GCM) Cipher Suites for TLS", RFC 5288, August 2008.August 2008[RFC4279]RFC 4279Eronen, P. and H. Tschofenig, "Pre-Shared Key Ciphersuites for Transport Layer Security (TLS)", RFC 4279, December 2005.December 2005
[GCM]Dworkin, M., "Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC", NIST SP 800-38D, November 2007.