Network Working Group                                            A. Kato
Internet-Draft                                                  S. Kanno
Intended status: Standards Track                NTT Software Corporation
Expires: March 13, 2010                                         M. Kanda
                                                                     NTT
                                                                T. Iwata
                                                       Nagoya University
                                                       September 9, 2009


 The Camellia-CMAC-96 and Camellia-CMAC-PRF-128 Algorithms and Its Use
                               with IPsec
               draft-kato-ipsec-camellia-cmac96and128-04

Status of this Memo

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Copyright Notice



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   Copyright (c) 2009 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 in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.











































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Abstract

   This memo specifies two new algorithms.  One is the usage of Cipher-
   based Message Authentication Code (CMAC) with Camellia block cipher
   on the authentication mechanism of the IPsec Encapsulating Security
   Payload and Authentication Header protocols.  This algorithm is
   called Camellia-CMAC-96.  Latter is pseudo-random function based on
   CMAC with Camellia block cipher for Internet Key Exchange.  This
   algorithm is called Camellia-CMAC-PRF-128.


Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . . .  5
   3.  Camellia-CMAC  . . . . . . . . . . . . . . . . . . . . . . . .  7
   4.  Camellia-CMAC-96 . . . . . . . . . . . . . . . . . . . . . . .  8
   5.  Camellia-CMAC-PRF-128  . . . . . . . . . . . . . . . . . . . .  9
   6.  Test Vectors . . . . . . . . . . . . . . . . . . . . . . . . . 11
     6.1.  Camellia-CMAC-96 . . . . . . . . . . . . . . . . . . . . . 11
     6.2.  Camellia-CMAC-PRF-128  . . . . . . . . . . . . . . . . . . 11
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 15
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 16
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
     10.1. Normative  . . . . . . . . . . . . . . . . . . . . . . . . 18
     10.2. Informative  . . . . . . . . . . . . . . . . . . . . . . . 18
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19






















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1.  Introduction

   This memo specifies two new algorithms.  One is the usage of CMAC
   based on Camellia block cipher on the authentication mechanism of the
   IPsec Encapsulating Security Payload (ESP) [6] and Authentication
   Header protocols (AH) [5].  This algorithm is called
   Camellia-CMAC-96.  Latter is Pseudo-Random Function (PRF) based on
   CMAC with Camellia block cipher for Internet Key Exchange (IKEv2)
   [7].  This algorithm is called Camellia-CMAC-PRF-128.

   The algorithm specification and object identifiers are described in
   [3].

   This document specifies the usage of CMAC with Camellia Block cipher
   on the authentication mechanism of the IPsec Encapsulating Security
   Payload [6] and Authentication Header [5] protocols.  This new
   algorithm is named Camellia-CMAC-96.

   NIST CMAC specification document [1] describes a method to use the
   Advanced Encryption Standard (AES) as a Message Authentication Code
   (MAC) that has a 128-bit output length.  The 128-bit output is useful
   as a long-lived PRF.  This document also specifies a PRF based on
   CMAC with Camellia block cipher that supports fixed and variable key
   sizes for IKEv2 [7] Key Derivation Function (KDF) and authentication.
   This new algorithm is named Camellia-CMAC-PRF-128.  For further
   information on IKE, AH and ESP, refer to [7], [5], [6], and [4].

   This document does not cover implementation details of CMAC.  Those
   details can be found in [1].

1.1.  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 [2].
















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2.  Definitions

   CBC
             Cipher Block Chaining mode of operation for message
             authentication code.

   MAC
             Message Authentication Code.  A bit string of a fixed
             length, computed by the MAC generation algorithm, that is
             used to establish the authority and, hence, the integrity
             of a message.

   CMAC
             Cipher-based MAC based on a symmetric key block cipher.

   Key (K)
             128-bit (16-octet) key for Camellia cipher block.  Denoted
             by K.

   Variable-length Key (VK)
             Variable-length key for Camellia-CMAC-PRF-128, denoted by
             VK.

   Message (M)
             Message to be authenticated.  Denoted by M.

   Length (len)
             The length of message M in octets.  Denoted by len.  The
             minimum value is 0.  The maximum value is not specified in
             this document.

   VKlen
             The length of VK in octets.

   truncate(T,l)
             Truncate T (MAC) in most-significant-bit-first (MSB-first)
             order to a length of l octets.

   T
             The output of Camellia-CMAC.

   Camellia-CMAC
             CMAC generation function based on Camellia block cipher
             with 128-bit key.







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   Camellia-CMAC-96
             IPsec AH and ESP MAC generation function based on Camellia-
             CMAC, which truncates the 96 most significant bits of the
             128-bit output.

   Camellia-CMAC-PRF-128
             IPsec AH and ESP PRF based on Camellia-CMAC, which removes
             128-bit key length restriction.

   SKEYSEED  Seed of shared key calculated from the nonces exchanged
             during the IKE_SA_INIT exchange and the Diffie-Hellman
             shared secret in IKEv2 specification.







































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3.  Camellia-CMAC

   The National Institute of Standards and Technology (NIST) has
   recently specified the Cipher-based Message Authentication Code
   (CMAC).  CMAC [1] is a keyed hash function that is based on a
   symmetric key block cipher, such as the Advanced Encryption Standard
   [9].  The CMAC algorithm provides a framework for inserting various
   block cipher algorithm.

   Camellia-CMAC uses the Camellia block cipher [3] as a building block
   in CMAC [1].  To generate a MAC, Camellia-CMAC(K, M, len) takes a
   secret key 'K', a message of variable length 'M', and the length of
   the message in octets 'len' as inputs and returns a fixed-bit string.

   In this specification, Camellia-CMAC is always used with 128-bit
   length key.



































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4.  Camellia-CMAC-96

   For IPsec message authentication on AH and ESP, Camellia-CMAC-96 MAY
   be used.  Camellia-CMAC-96 is a Camellia-CMAC with 96-bit truncated
   output in MSB-first order.  The output is a 96-bit MAC that will meet
   the default authenticator length as specified in [5].  The result of
   truncation is taken in MSB-first order.

   Figure 1 describes Camellia-CMAC-96 algorithm:

   In step 1, Camellia-CMAC is applied to the message M in length len
   with key K.

   In step 2, the output block T is truncated to 12 octets in MSB-first
   order, and Truncated T (TT) is returned.

   +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   +                    Algorithm Camellia-CMAC-96                     +
   +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   +                                                                   +
   +   Input    : K (128-bit Key)                                      +
   +            : M    (message to be authenticated)                   +
   +            : len  (length of message in octets)                   +
   +   Output   : Truncated T  (truncated output to length 12 octets)  +
   +                                                                   +
   +-------------------------------------------------------------------+
   +                                                                   +
   +   Step 1.  T  := Camellia-CMAC (K,M,len);                         +
   +   Step 2.  TT := truncate (T, 12);                                +
   +            return TT;                                             +
   +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

                   Figure 1: Algorithm Camellia-CMAC-96


















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5.  Camellia-CMAC-PRF-128

   The Camellia-CMAC-PRF-128 algorithm is identical to Camellia-CMAC
   except that the 128-bit key length restriction is removed.

   IKEv2 [7] uses PRFs for multiple purposes, most notably for
   generating keying material and authentication of the IKE_SA.

   When using Camellia-CMAC-PRF-128 as the PRF described in IKEv2,
   Camellia-CMAC-PRF-128 is considered to take variable key length in
   all places, and the number of bits of keying material generated when
   new keys are generated is 128 bits (i.e. preferred key length when
   generating keying material of SK_d, SK_pi, and SK_pr is 128 bits).

   When generating SKEYSEED the full of Ni and Nr are used as key for
   the PRF.

   +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   +                        Camellia-CMAC-PRF-128                      +
   +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
   +                                                                   +
   + Input  : VK (Variable-length key)                                 +
   +        : M (Message, i.e., the input data of the PRF)             +
   +        : VKlen (length of VK in octets)                           +
   +        : len (length of M in octets)                              +
   + Output : PRV (128-bit Pseudo-Random Variable)                     +
   +                                                                   +
   +-------------------------------------------------------------------+
   + Variable: K (128-bit key for Camellia-CMAC)                       +
   +                                                                   +
   + Step 1.   If VKlen is equal to 16                                 +
   + Step 1a.  then                                                    +
   +               K := VK;                                            +
   + Step 1b.  else                                                    +
   +               K := Camellia-CMAC(0^128, VK, VKlen);               +
   + Step 2.   PRV := Camellia-CMAC(K, M, len);                        +
   +           return PRV;                                             +
   +                                                                   +
   +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

                 Figure 2: Algorithm Camellia-CMAC-PRF-128

   In step 1, the 128-bit key, K, for Camellia-CMAC is derived as
   follows:







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   o  If the key, VK, is exactly 128 bits, then we use it as-is.

   o  If it is longer or shorter than 128 bits, then we derive the key,
      K, by applying the Camellia-CMAC algorithm using the 128-bit all-
      zero string as the key and VK as the input message.  This step is
      described in step 1b.

   In step 2, we apply the Camellia-CMAC algorithm using K as the key
   and M as the input message.  The output of this algorithm is
   returned.









































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6.  Test Vectors

6.1.  Camellia-CMAC-96

   This section contains four test vectors(TV), which can be used to
   confirm that an implementation has correctly implemented Camellia-
   CMAC-96.


    ----------------
    K                2b7e1516 28aed2a6 abf71588 09cf4f3c

    Mlen = 0
    M                <empty string>
    T                ba925782 aaa1f5d9 a00f8964

    ----------------
    K                2b7e1516 28aed2a6 abf71588 09cf4f3c

    Mlen = 16
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
    T                6d962854 a3b9fda5 6d7d45a9

    ----------------
    K                2b7e1516 28aed2a6 abf71588 09cf4f3c

    Mlen = 40
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
                     ae2d8a57 1e03ac9c 9eb76fac 45af8e51
                     30c81c46 a35ce411
    T                5c18d119 ccd67661 44ac1866

    ----------------
    K                2b7e1516 28aed2a6 abf71588 09cf4f3c

    Mlen = 64
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
                     ae2d8a57 1e03ac9c 9eb76fac 45af8e51
                     30c81c46 a35ce411 e5fbc119 1a0a52ef
                     f69f2445 df4f9b17 ad2b417b e66c3710
    T                c2699a6e ba55ce9d 939a8a4e

6.2.  Camellia-CMAC-PRF-128

   This section contains twelve test vectors(TV), which can be used to
   confirm that an implementation has correctly implemented Camellia-
   CMAC-PRF-128.  The first four test vectors use 128 bit VK; the next
   four test vectors use 192 bit VK; and the last four test vectors use



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   256 bit VK.

   VKlen = 16
    ----------------
    VK               2b7e1516 28aed2a6 abf71588 09cf4f3c


    Mlen = 0
    M                <empty string>
    T                ba925782 aaa1f5d9 a00f8964 8094fc71

    ----------------
    VK               2b7e1516 28aed2a6 abf71588 09cf4f3c


    Mlen = 16
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
    T                6d962854 a3b9fda5 6d7d45a9 5ee17993

    ----------------
    VK               2b7e1516 28aed2a6 abf71588 09cf4f3c


    Mlen = 40
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
                     ae2d8a57 1e03ac9c 9eb76fac 45af8e51
                     30c81c46 a35ce411
    T                5c18d119 ccd67661 44ac1866 131d9f22

    ----------------
    VK               2b7e1516 28aed2a6 abf71588 09cf4f3c


    Mlen = 64
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
                     ae2d8a57 1e03ac9c 9eb76fac 45af8e51
                     30c81c46 a35ce411 e5fbc119 1a0a52ef
                     f69f2445 df4f9b17 ad2b417b e66c3710
    T                c2699a6e ba55ce9d 939a8a4e 19466ee9

    ------------------------------------------------------------
    VKlen = 24
    ----------------
    VK               8e73b0f7 da0e6452 c810f32b 809079e5
                     62f8ead2 522c6b7b

    K                abddaa68 e8b9f0af 2fb4db53 41cf1d91




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    Mlen = 0
    M                <empty string>
    T                f4739892 c70bd23e 891f66c0 5fefbf27

    ----------------
    VK               8e73b0f7 da0e6452 c810f32b 809079e5
                     62f8ead2 522c6b7b

    K                abddaa68 e8b9f0af 2fb4db53 41cf1d91

    Mlen = 16
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
    T                60a33814 53babaed 1a11dfd3 d24c1410

    ----------------
    VK               8e73b0f7 da0e6452 c810f32b 809079e5
                     62f8ead2 522c6b7b

    K                abddaa68 e8b9f0af 2fb4db53 41cf1d91

    Mlen = 40
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
                     ae2d8a57 1e03ac9c 9eb76fac 45af8e51
                     30c81c46 a35ce411
    T                42b9d47f 4f58bc29 85b6f82c 23b121cb

    ----------------
    VK               8e73b0f7 da0e6452 c810f32b 809079e5
                     62f8ead2 522c6b7b

    K                abddaa68 e8b9f0af 2fb4db53 41cf1d91

    Mlen = 64
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
                     ae2d8a57 1e03ac9c 9eb76fac 45af8e51
                     30c81c46 a35ce411 e5fbc119 1a0a52ef
                     f69f2445 df4f9b17 ad2b417b e66c3710
    T                d078729f dcae9abc ff1ea4d6 18ed4501

    ------------------------------------------------------------
    VKlen = 32
    ----------------
    VK               603deb10 15ca71be 2b73aef0 857d7781
                     1f352c07 3b6108d7 2d9810a3 0914dff4

    K                b5aeeae9 2c23bed7 167af194 2e831597

    Mlen = 0



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    M                <empty string>
    T                c96d7d40 d4aaab78 ac906b91 c82bd690

    ----------------
    VK               603deb10 15ca71be 2b73aef0 857d7781
                     1f352c07 3b6108d7 2d9810a3 0914dff4

    K                b5aeeae9 2c23bed7 167af194 2e831597

    Mlen = 16
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
    T                104de4b9 0da6baf1 fa73945b e614f032

    ----------------
    VK               603deb10 15ca71be 2b73aef0 857d7781
                     1f352c07 3b6108d7 2d9810a3 0914dff4

    K                b5aeeae9 2c23bed7 167af194 2e831597

    Mlen = 40
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
                     ae2d8a57 1e03ac9c 9eb76fac 45af8e51
                     30c81c46 a35ce411
    T                2d3684e9 1cb1b303 a7db8648 f25ee16c

    ----------------
    VK               603deb10 15ca71be 2b73aef0 857d7781
                     1f352c07 3b6108d7 2d9810a3 0914dff4

    K                b5aeeae9 2c23bed7 167af194 2e831597

    Mlen = 64
    M                6bc1bee2 2e409f96 e93d7e11 7393172a
                     ae2d8a57 1e03ac9c 9eb76fac 45af8e51
                     30c81c46 a35ce411 e5fbc119 1a0a52ef
                     f69f2445 df4f9b17 ad2b417b e66c3710
    T                d6b0f1b7 dda2b62a eca6d51d da63fdda














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7.  Security Considerations

   The security provided by Camellia-CMAC-96 Camellia-CMAC-PRF-128 is
   built on the strong cryptographic algorithm Camellia and CMAC.  At
   the time of this writing, there are no known practical cryptographic
   attacks against Camellia or CMAC.

   However, as is true with any cryptographic algorithm, part of its
   strength lies in the secret key, K, and the correctness of the
   implementation in all of the participating systems.  If the secret
   key is compromised or inappropriately shared, it guarantees neither
   authentication nor integrity of message at all.  The secret key shall
   be generated in a way that meets the pseudo randomness requirement of
   RFC 4086 [8] and should be kept safe.  If and only if
   Camellia-CMAC-96 Camellia-CMAC-PRF-128 are used properly it provides
   the authentication and integrity that meet the best current practice
   of message authentication.


































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8.  IANA Considerations

   The IANA has allocated value <TBD1> for IKEv2 Transform Type 3
   (Integrity Algorithm) to the AUTH_CAMELLIA_CMAC_96 algorithm, and has
   allocated a value of <TBD2> for IKEv2 Transform Type 2 (Pseudo-Random
   Function) to the PRF_CAMELLIA128_CMAC algorithm.













































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9.  Acknowledgements

   We thank Tim Polk and Tero Kivinen for their initial review of this
   document.















































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10.  References

10.1.  Normative

   [1]  National Institute of Standards and Technology, "Recommendation
        for Block Cipher Modes of Operation:The CMAC Mode for
        Authentication", Special Publication 800-38B, May 2005.

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

   [3]  Matsui, M., Nakajima, J., and S. Moriai, "A Description of the
        Camellia Encryption Algorithm", RFC 3713, April 2004.

10.2.  Informative

   [4]  Thayer, R., Doraswamy, N., and R. Glenn, "IP Security Document
        Roadmap", RFC 2411, November 1998.

   [5]  Kent, S., "IP Authentication Header", RFC 4302, December 2005.

   [6]  Kent, S., "IP Encapsulating Security Payload (ESP)", RFC 4303,
        December 2005.

   [7]  Kaufman, C., Hoffman, P., and P. Eronen, "Internet Key Exchange
        Protocol: IKEv2", draft-hoffman-ikev2bis-03 (work in progress),
        February 2008.

   [8]  Eastlake, D., Schiller, J., and S. Crocker, "Randomness
        Requirements for Security", BCP 106, RFC 4086, June 2005.

   [9]  National Institute of Standards and Technology, "Advanced
        Encryption Standard (AES)", FIPS PUB 197, November 2001,
        <http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf>.

















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Authors' Addresses

   Akihiro Kato
   NTT Software Corporation

   Phone: +81-45-212-7577
   Fax:   +81-45-212-9800
   Email: kato.akihiro@po.ntts.co.jp


   Satoru Kanno
   NTT Software Corporation

   Phone: +81-45-212-7577
   Fax:   +81-45-212-9800
   Email: kanno.satoru@po.ntts.co.jp


   Masayuki Kanda
   NTT

   Phone: +81-422-59-3456
   Fax:   +81-422-59-4015
   Email: kanda.masayuki@lab.ntt.co.jp


   Tetsu Iwata
   Nagoya University

   Email: iwata@cse.nagoya-u.ac.jp





















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