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Versions: 00 draft-ietf-avtcore-aria-srtp

AVTCore                                                           W. Kim
Internet-Draft                                                    J. Lee
Intended status: Standards Track                                  D. Kim
Expires: August 25, 2012                                         J. Park
                                                                 D. Kwon
                                                                    NSRI
                                                       February 22, 2012


   The ARIA Algorithm and Its Use with the Secure Real-time Transport
                             Protocol(SRTP)
                    draft-nsri-avtcore-aria-srtp-00

Abstract

   This document describes the use of the ARIA block cipher algorithm
   within the Secure Real-time Transport Protocol (SRTP) for providing
   confidentiality for the Real-time Transport Protocol (RTP) traffic
   and for the control traffic for RTP, the Real-time Transport Control
   Protocol (RTCP).  It details three modes of operation (CTR, CCM, GCM)
   and a SRTP Key Derivation Function for ARIA.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   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."

   This Internet-Draft will expire on August 25, 2012.

Copyright Notice

   Copyright (c) 2012 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



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   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  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  ARIA  . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Cryptographic Transforms  . . . . . . . . . . . . . . . . . . . 3
     2.1.  ARIA-CTR  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     2.2.  ARIA-CCM and ARIA-GCM . . . . . . . . . . . . . . . . . . . 4
   3.  ARIA-CTR PRF  . . . . . . . . . . . . . . . . . . . . . . . . . 5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 7
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 7
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 8































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1.  Introduction

   This document describes the use of the ARIA [RFC5794] block cipher
   algorithm in the Secure Real-time Transport Protocol (SRTP) [RFC3711]
   for providing confidentiality for the Real-time Transport Protocol
   (RTP) [RFC3550] traffic and for the control traffic for RTP, the
   Real-time Transport Control Protocol (RTCP) [RFC3550].

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.  Cryptographic Transforms

   Block ciphers ARIA and AES share common characteristics including
   mode, key size, and block size.  ARIA does not have any restrictions
   for modes of operation that are used with this block cipher.  We
   define three modes of running ARIA within the SRTP protocol, (1) ARIA
   in Counter Mode, (2) ARIA in Counter with CBC-MAC (CCM) Mode and (3)
   ARIA in Galois/Counter Mode (GCM).

2.1.  ARIA-CTR

   Section 4.1.1 of [RFC3711] defines AES-128 counter mode encryption,
   which it refers to as "AES_CM".  Section 2 of [RFC6188] defines
   "AES_192_CM" and "AES_256_CM" in SRTP.  ARIA counter modes are
   defined in a similar manner, and are denoted by ARIA_128_CTR,
   ARIA_192_CTR and ARIA_256_CTR respectively, according to the key
   lengths.  The plaintext inputs to the block cipher are formed as in
   AES-CTR(AES_CM, AES_192_CM, AES_256_CM) and the block cipher outputs
   are processed as in AES-CTR.  The only difference in the processing
   is that ARIA-CTR uses ARIA as the underlying encryption primitive.
   When ARIA-CTR is used, it MUST be used only in conjunction with an



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   authentication function.

   The ARIA-CTR ciphersuites with HMAC-SHA1 as an authentication
   function are listed below.  For each ciphersuites, the authentication
   key size is 20 octets.

         Name                       Enc. Key Size  Auth. Tag Size
         =========================================================
         ARIA_128_CTR_HMAC_SHA1_80  16 octets      10 octets
         ARIA_128_CTR_HMAC_SHA1_32  16 octets      4 octets
         ARIA_192_CTR_HMAC_SHA1_80  24 octets      10 octets
         ARIA_192_CTR_HMAC_SHA1_32  24 octets      4 octets
         ARIA_256_CTR_HMAC_SHA1_80  32 octets      10 octets
         ARIA_256_CTR_HMAC_SHA1_32  32 octets      4 octets

               Figure 1: ARIA-CTR algorithms for SRTP/SRTCP

2.2.  ARIA-CCM and ARIA-GCM

   CCM(Counter with CBC-MAC) [RFC3610] and GCM(Galois Counter Mode)
   [GCM] are AEAD(authenticated encryption with associated data) block
   cipher modes.  ARIA-CCM and ARIA-GCM are defined similarly as AES-CCM
   and AES-GCM.

   The internet draft [I-D.mcgrew-tls-aes-ccm] describes the use of AES-
   GCM and AES-CCM with SRTP.  The use of ARIA-CCM and ARIA-GCM with
   SRTP is defined the same as that of AES-CCM and AES-GCM.

   The following members of the ARIA-GCM family may be used with SRTP/
   SRTCP:

            Name                  Key Size      Auth. Tag Size
            ====================================================
            AEAD_ARIA_128_GCM     16 octets     16 octets
            AEAD_ARIA_256_GCM     32 octets     16 octets
            AEAD_ARIA_128_GCM_8   16 octets     8 octets
            AEAD_ARIA_256_GCM_8   32 octets     8 octets
            AEAD_ARIA_128_GCM_12  16 octets     12 octets
            AEAD_ARIA_256_GCM_12  32 octets     12 octets

               Figure 2: ARIA-GCM algorithms for SRTP/SRTCP










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   The following members of the ARIA-CCM family may be used with SRTP/
   SRTCP:

            Name                  Key Size      Auth. Tag Size
            ====================================================
            AEAD_ARIA_128_CCM     16 octets     16 octets
            AEAD_ARIA_256_CCM     32 octets     16 octets

               Figure 3: ARIA-CCM algorithms for SRTP/SRTCP

3.  ARIA-CTR PRF

   Section 4.3.3 of [RFC3711] defines the AES-128 counter mode key
   derivation function, which it refers to as "AES-CM PRF".  Section 3
   of [RFC6188] defines the AES-192 counter mode key derivation function
   and the AES-256 counter mode key derivation function, which it refers
   to as "AES_192_CM_PRF" and "AES_256_CM_PRF" respectively.  The ARIA-
   CTR PRF is defined in a similar manner, but with each invocation of
   AES replaced with an invocation of ARIA.  According to the key
   lengths of underlying encryption algorithm, ARIA-CTR PRFs are denoted
   by "ARIA_128_CTR_PRF", "ARIA_192_CTR_PRF" and "ARIA_256_CTR_PRF".
   The usage requirements of [RFC6188] regarding the AES-CM PRF apply to
   the ARIA-CTR PRF as well.  The PRFs for ARIA ciphersuites with SRTP
   are defined by ARIA-CTR PRF of the equal key length with the
   encryption algorithm.

4.  Security Considerations

   At the time of writing this document no security problem has been
   found on ARIA (see [TSL]).

   The security considerations in [RFC3610] [GCM] [RFC3711] [RFC6188]
   [I-D.mcgrew-tls-aes-ccm] apply to this document as well.


















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5.  IANA Considerations

   [RFC4568] defines SRTP "crypto suites".  In order to allow SDP to
   signal the use of the algorithms defined in this document, IANA is
   requested to register the following crypto suites into the sub-
   registry for SRTP crypto suites under the SRTP transport of the SDP
   Security Descriptions:

            srtp-crypto-suite-ext = "ARIA_128_CTR_HMAC_SHA1_80"/
                                    "ARIA_128_CTR_HMAC_SHA1_32"/
                                    "ARIA_192_CTR_HMAC_SHA1_80"/
                                    "ARIA_192_CTR_HMAC_SHA1_32"/
                                    "ARIA_256_CTR_HMAC_SHA1_80"/
                                    "ARIA_256_CTR_HMAC_SHA1_32"/
                                    "AEAD_ARIA_128_GCM"        /
                                    "AEAD_ARIA_256_GCM"        /
                                    "AEAD_ARIA_128_GCM_8"      /
                                    "AEAD_ARIA_256_GCM_8"      /
                                    "AEAD_ARIA_128_GCM_12"     /
                                    "AEAD_ARIA_256_GCM_12"     /
                                    "AEAD_ARIA_128_CCM"        /
                                    "AEAD_ARIA_256_CCM"        /
                                    srtp-crypto-suite-ext

   DTLS-SRTP[RFC5764] defines a DTLS-SRTP "SRTP Protection Profile".  In
   order to allow the use of the algorithms defined in this document in
   DTLS-SRTP, IANA will also register the following SRTP Protection
   Profiles:

                SRTP_ARIA_128_CTR_HMAC_SHA1_80  = {TBD,TBD};
                SRTP_ARIA_128_CTR_HMAC_SHA1_32  = {TBD,TBD};
                SRTP_ARIA_192_CTR_HMAC_SHA1_80  = {TBD,TBD};
                SRTP_ARIA_192_CTR_HMAC_SHA1_32  = {TBD,TBD};
                SRTP_ARIA_256_CTR_HMAC_SHA1_80  = {TBD,TBD};
                SRTP_ARIA_256_CTR_HMAC_SHA1_32  = {TBD,TBD};
                SRTP_AEAD_ARIA_128_GCM          = {TBD,TBD};
                SRTP_AEAD_ARIA_256_GCM          = {TBD,TBD};
                SRTP_AEAD_ARIA_128_GCM_8        = {TBD,TBD};
                SRTP_AEAD_ARIA_256_GCM_8        = {TBD,TBD};
                SRTP_AEAD_ARIA_128_GCM_12       = {TBD,TBD};
                SRTP_AEAD_ARIA_256_GCM_12       = {TBD,TBD};
                SRTP_AEAD_ARIA_128_CCM          = {TBD,TBD};
                SRTP_AEAD_ARIA_256_CCM          = {TBD,TBD};








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   [RFC3830] and [RFC5748] define encryption algorithms and PRFs for the
   SRTP policy in MIKEY.  In order to allow the use of the algorithms
   defined in this document in MIKEY, IANA is requested to allocate the
   following numbers in the MIKEY sub-registries.

                       SRTP Enc. alg  | Value
                       ----------------------
                       NULL           |     0
                       AES-CM         |     1
                       AES-F8         |     2
                       SEED-CTR       |     3
                       SEED-CCM       |     4
                       SEED-GCM       |     5
                       ARIA-128-CTR   |     6 (NEW)
                       ARIA-128-CCM   |     7 (NEW)
                       ARIA-128-GCM   |     8 (NEW)
                       ARIA-128-GCM-8 |     9 (NEW)
                       ARIA-128-GCM-12|     10 (NEW)

                Figure 4: Figure 1 from RFC 5748 (revised)


                        SRTP PRF      | Value
                        ---------------------
                        AES-CM        |     0
                        SEED-CTR      |     1
                        ARIA-128-CTR  |     2 (NEW)

                Figure 5: Figure 2 from RFC 5748 (revised)

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.

   [RFC3550]                 Schulzrinne, H., Casner, S., Frederick, R.,
                             and V. Jacobson, "RTP: A Transport Protocol
                             for Real-Time Applications", STD 64,
                             RFC 3550, July 2003.




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   [RFC3711]                 Baugher, M., McGrew, D., Naslund, M.,
                             Carrara, E., and K. Norrman, "The Secure
                             Real-time Transport Protocol (SRTP)",
                             RFC 3711, March 2004.

   [RFC3830]                 Arkko, J., Carrara, E., Lindholm, F.,
                             Naslund, M., and K. Norrman, "MIKEY:
                             Multimedia Internet KEYing", RFC 3830,
                             August 2004.

   [RFC4568]                 Andreasen, F., Baugher, M., and D. Wing,
                             "Session Description Protocol (SDP)
                             Security Descriptions for Media Streams",
                             RFC 4568, July 2006.

   [RFC5764]                 McGrew, D. and E. Rescorla, "Datagram
                             Transport Layer Security (DTLS) Extension
                             to Establish Keys for the Secure Real-time
                             Transport Protocol (SRTP)", RFC 5764,
                             May 2010.

   [RFC6188]                 McGrew, D., "The Use of AES-192 and AES-256
                             in Secure RTP", RFC 6188, March 2011.

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.

   [I-D.mcgrew-tls-aes-ccm]  McGrew, D. and D. Bailey, "AES-CCM Cipher
                             Suites for TLS",
                             draft-mcgrew-tls-aes-ccm-03 (work in
                             progress), February 2012.

   [RFC3610]                 Whiting, D., Housley, R., and N. Ferguson,
                             "Counter with CBC-MAC (CCM)", RFC 3610,
                             September 2003.

   [RFC5748]                 Yoon, S., Jeong, J., Kim, H., Jeong, H.,
                             and Y. Won, "IANA Registry Update for
                             Support of the SEED Cipher Algorithm in
                             Multimedia Internet KEYing (MIKEY)",



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                             RFC 5748, August 2010.

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

   [TSL]                     Tang, X., Sun, B., Li, R., Li, C., and J.
                             Yin, "A meet-in-the-middle attack on
                             reduced-round ARIA", The Journal of Systems
                             and Software Vol.84(10), pp. 1685-1692,
                             October 2011.

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


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

   EMail: dongchan@ensec.re.kr












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   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



































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