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Versions: (draft-ietf-kitten-aes-cbc-hmac-sha2) 00 01 02 03 04 05 06 07 08 09 10 11 RFC 8009

Network Working Group                                         M. Jenkins
Internet Draft                                  National Security Agency
Intended Status: Informational                                   M. Peck
Expires: August 13, 2015                           The MITRE Corporation
                                                               K. Burgin
                                                        February 9, 2015

              AES Encryption with HMAC-SHA2 for Kerberos 5
                 draft-ietf-kitten-aes-cts-hmac-sha2-06

Abstract

   This document specifies two encryption types and two corresponding
   checksum types for Kerberos 5.  The new types use AES in CTS mode
   (CBC mode with ciphertext stealing) for confidentiality and HMAC with
   a SHA-2 hash for integrity.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   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 13, 2015.

Copyright and License Notice

   Copyright (c) 2015 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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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Protocol Key Representation  . . . . . . . . . . . . . . . . .  3
   3.  Key Derivation Function  . . . . . . . . . . . . . . . . . . .  3
   4.  Key Generation from Pass Phrases . . . . . . . . . . . . . . .  4
   5.  Kerberos Algorithm Protocol Parameters . . . . . . . . . . . .  5
   6.  Checksum Parameters  . . . . . . . . . . . . . . . . . . . . .  7
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  7
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . .  8
     8.1.  Random Values in Salt Strings  . . . . . . . . . . . . . .  8
     8.2.  Algorithm Rationale  . . . . . . . . . . . . . . . . . . .  9
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  9
   10.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  9
     10.1.  Normative References  . . . . . . . . . . . . . . . . . .  9
     10.2.  Informative References  . . . . . . . . . . . . . . . . .  9
   Appendix A.  Test Vectors  . . . . . . . . . . . . . . . . . . . . 10
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16

































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1.  Introduction

   This document defines two encryption types and two corresponding
   checksum types for Kerberos 5 using AES with 128-bit or 256-bit keys.

   To avoid ciphertext expansion, we use a variation of the CBC-CS3 mode
   defined in [SP800-38A+], also referred to as ciphertext stealing or
   CTS mode.  The new types conform to the framework specified in
   [RFC3961], but do not use the simplified profile.

   The encryption and checksum types defined in this document are
   intended to support environments that desire to use SHA-256 or SHA-
   384 as the hash algorithm.  Differences between the encryption and
   checksum types defined in this document and the pre-existing Kerberos
   AES encryption and checksum types specified in [RFC3962] are:

   *  The pseudorandom function used by PBKDF2 is HMAC-SHA-256 or HMAC-
      SHA-384.

   *  A key derivation function from [SP800-108] using the SHA-256 or
      SHA-384 hash algorithm is used to produce keys for encryption,
      integrity protection, and checksum operations.

   *  The HMAC is calculated over the cipherstate concatenated with the
      AES output, instead of being calculated over the confounder and
      plaintext.  This allows the message receiver to verify the
      integrity of the message before decrypting the message.

   *  The HMAC algorithm uses the SHA-256 or SHA-384 hash algorithm for
      integrity protection and checksum operations.

2.  Protocol Key Representation

   The AES key space is dense, so we can use random or pseudorandom
   octet strings directly as keys.  The byte representation for the key
   is described in [FIPS197], where the first bit of the bit string is
   the high bit of the first byte of the byte string (octet string).

3.  Key Derivation Function

   We use a key derivation function from Section 5.1 of [SP800-108]
   which uses the HMAC algorithm as the PRF.  All octets are expressed
   in big-endian order.  The counter i is expressed as four octets and
   in this document is always 0x00000001 since there is only a single
   iteration of the PRF.  The "Label" input to the NIST KDF is the
   constant supplied to this key derivation function.  When deriving Kc,
   Ki, or Ke, the constant is the four octet key usage concatenated with
   0x99, 0x55, or 0xAA respectively.  When deriving the base-key, the



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   constant is the ASCII string "kerberos", also known as the byte
   string 0x6B65726265726F73.  When deriving Kp, the constant is the
   ASCII string "prf", also known as the byte string 0x707266.  The
   "Context" input is omitted.  The length of the output key in bits
   (denoted as k) is also represented as four octets in big-endian
   order.  Each application of the KDF only requires a single iteration
   of the PRF, so n = 1 in the notation of [SP800-108].  The purposes of
   the Kc, Ki, Ke, base-key, and Kp keys are described in Section 5.

   In the following summary, | indicates concatenation.  The random-to-
   key function is the identity function.  The k-truncate function is
   defined in [RFC3961], Section 5.1.

   When the encryption type is aes128-cts-hmac-sha256-128, the output
   key length k is 128 bits for all applications of KDF-HMAC-SHA2(key,
   constant) which is computed as follows:

     K1 = HMAC-SHA-256(key, 00 00 00 01 | constant | 00 | 00 00 00 80)
     KDF-HMAC-SHA2(key, constant) = random-to-key(k-truncate(K1))

   When the encryption type is aes256-cts-hmac-sha384-192, the output
   key length k is 256 bits when deriving the base-key (from a
   passphrase as described in Section 4), Ke, and Kp.  The output key
   length k is 192 bits when deriving Kc and Ki.  KDF-HMAC-SHA2(key,
   constant) is computed as follows:

     If deriving Kc or Ki (the constant ends with 0x99 or 0x55):
     k = 192
     K1 = HMAC-SHA-384(key, 00 00 00 01 | constant | 00 | 00 00 00 C0)
     KDF-HMAC-SHA2(key, constant) = random-to-key(k-truncate(K1))

     If deriving the base-key (the constant is "kerberos", the byte
     string 0x6B65726265726F73), Ke (the constant ends with 0xAA),
     or Kp (the constant is "prf", the byte string 0x707266):
     k = 256
     K1 = HMAC-SHA-384(key, 00 00 00 01 | constant | 00 | 00 00 01 00)
     KDF-HMAC-SHA2(key, constant) = random-to-key(k-truncate(K1))

4.  Key Generation from Pass Phrases

     PBKDF2 [RFC2898] is used to derive the base-key from a passphrase
     and salt.

     If no string-to-key parameters are specified, the default number of
     iterations is 32,768.

     To ensure that different long-term base-keys are used with
     different enctypes, we prepend the enctype name to the salt,



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     separated by a null byte.  The enctype-name is "aes128-cts-hmac-
     sha256-128" or "aes256-cts-hmac-sha384-192" (without the quotes).
     The user's long-term base-key is derived as follows

     saltp = enctype-name | 0x00 | salt
     tkey = random-to-key(PBKDF2(passphrase, saltp,
                              iter_count, keylength))
     base-key = KDF-HMAC-SHA2(tkey, "kerberos") where "kerberos" is the
                byte string {0x6B65726265726F73}.

   where the pseudorandom function used by PBKDF2 is HMAC-SHA-256 when
   the enctype is "aes128-cts-hmac-sha256-128" and HMAC-SHA-384 when the
   enctype is "aes256-cts-hmac-sha384-192", the value for keylength is
   the AES key length (128 or 256 bits), and the algorithm KDF-HMAC-SHA2
   is defined in Section 3.

5.  Kerberos Algorithm Protocol Parameters

   The cipherstate is used as the formal initialization vector (IV)
   input into CBC-CS3.  The plaintext is prepended with a 16-octet
   random nonce generated by the message originator, known as a
   confounder.

   The ciphertext is a concatenation of the output of AES in CBC-CS3
   mode and the HMAC of the cipherstate concatenated with the AES
   output.  The HMAC is computed using either SHA-256 or SHA-384
   depending on the encryption type.  The output of HMAC-SHA-256 is
   truncated to 128 bits and the output of HMAC-SHA-384 is truncated to
   192 bits. Sample test vectors are given in Appendix A.

   Decryption is performed by removing the HMAC, verifying the HMAC
   against the cipherstate concatenated with the ciphertext, and then
   decrypting the ciphertext if the HMAC is correct.  Finally, the first
   16 octets of the decryption output (the confounder) is discarded, and
   the remainder is returned as the plaintext decryption output.

   The following parameters apply to the encryption types aes128-cts-
   hmac-sha256-128 and aes256-cts-hmac-sha384-192.

   protocol key format: as defined in Section 2.

   specific key structure: three protocol-format keys: { Kc, Ke, Ki }.

   Kc: the checksum key, inputted into HMAC to provide the checksum
   mechanism defined in Section 6.

   Ke: the encryption key, inputted into AES encryption and decryption
   as defined in "encryption function" and "decryption function" below.



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   Ki: the integrity key, inputted into HMAC to provide authenticated
   encryption as defined in "encryption function" and "decryption
   function" below.

   required checksum mechanism: as defined in Section 6.

   key-generation seed length: key size (128 or 256 bits).

   string-to-key function: as defined in Section 4.

   default string-to-key parameters: 00 00 80 00.

   random-to-key function: identity function.

   key-derivation function: KDF-HMAC-SHA2 as defined in Section 3.  The
   key usage number is expressed as four octets in big-endian order.

   Kc = KDF-HMAC-SHA2(base-key, usage | 0x99)
   Ke = KDF-HMAC-SHA2(base-key, usage | 0xAA)
   Ki = KDF-HMAC-SHA2(base-key, usage | 0x55)

   cipherstate: a 128-bit CBC initialization vector derived from
   the ciphertext.

   initial cipherstate: all bits zero.

   encryption function: as follows, where E() is AES encryption in
   CBC-CS3 mode, and h is the size of truncated HMAC.

      N = random nonce of length 128 bits (the AES block size)
      IV = cipherstate
      C = E(Ke, N | plaintext, IV)
      H = HMAC(Ki, IV | C)
      ciphertext = C | H[1..h]
      cipherstate = the last full (128 bit) block of C
      (i.e. the next-to-last block if the last block
      is not a full 128 bits)

   decryption function: as follows, where D() is AES decryption in
   CBC-CS3 mode, and h is the size of truncated HMAC.

      (C, H) = ciphertext
      IV = cipherstate
      if H != HMAC(Ki, IV | C)[1..h]
          stop, report error
      (N, P) = D(Ke, C, IV)
      Note: N is set to the first block of the decryption output,
      P is set to the rest of the output.



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      cipherstate = the last full (128 bit) block of C
      (i.e. the next-to-last block if the last block
      is not a full 128 bits)

   pseudo-random function:
      If the enctype is aes128-cts-hmac-sha256-128:
      k = 128

      If the enctype is aes256-cts-hmac-sha384-192:
      k = 256

      Kp  = KDF-HMAC-SHA2(base-key, "prf")
      PRF = k-truncate(HMAC-SHA2(Kp, octet-string))

      where SHA2 is SHA-256 if the enctype is
      aes128-cts-hmac-sha256-128,
      and is SHA-384 if the enctype is aes256-cts-hmac-sha384-192.

6.  Checksum Parameters

   The following parameters apply to the checksum types hmac-sha256-128-
   aes128 and hmac-sha384-192-aes256, which are the associated checksums
   for aes128-cts-hmac-sha256-128 and aes256-cts-hmac-sha384-192,
   respectively.

   associated cryptosystem: AES-128-CTS or AES-256-CTS as appropriate.

   get_mic: HMAC(Kc, message)[1..h].

   verify_mic: get_mic and compare.


7.  IANA Considerations

   IANA is requested to assign:

   Encryption type numbers for aes128-cts-hmac-sha256-128 and
   aes256-cts-hmac-sha384-192 in the Kerberos Encryption Type Numbers
   registry.

      Etype   encryption type              Reference
      -----   ---------------              ---------
      TBD1    aes128-cts-hmac-sha256-128   [this document]
      TBD2    aes256-cts-hmac-sha384-192   [this document]

   Checksum type numbers for hmac-sha256-128-aes128 and hmac-sha384-192-
   aes256 in the Kerberos Checksum Type Numbers registry.




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      Sumtype   Checksum type            Size   Reference
      -------   -------------            ----   ---------
      TBD3      hmac-sha256-128-aes128   16     [this document]
      TBD4      hmac-sha384-192-aes256   24     [this document]


8.  Security Considerations

   This specification requires implementations to generate random
   values.  The use of inadequate pseudo-random number generators
   (PRNGs) can result in little or no security.  The generation of
   quality random numbers is difficult.  [RFC4086] offers random number
   generation guidance.

   This document specifies a mechanism for generating keys from pass
   phrases or passwords.  The salt and iteration count resist brute
   force and dictionary attacks, however, it is still important to
   choose or generate strong passphrases.

   NIST guidance in section 5.3 of [SP800-38A] requires CBC
   initialization vectors be unpredictable.  This specification does not
   formally comply with that guidance.  However, the use of a confounder
   as the first block of plaintext fills the cryptographic role
   typically played by an initialization vector.  This approach was
   chosen to align with other Kerberos cryptosystem approaches.

8.1.  Random Values in Salt Strings

   NIST guidance in Section 5.1 of [SP800-132] requires that a portion
   of the salt of at least 128 bits shall be randomly generated.  Some
   known issues with including random values in Kerberos encryption type
   salt strings are:

   *  The string-to-key function as defined in [RFC3961] requires the
      salt to be valid UTF-8 strings.  Not every 128-bit random string
      will be valid UTF-8.

   Further, using a salt containing a random portion may have the
   following issues with some implementations:

   *  Cross-realm TGTs are typically managed by entering the same
   password at two KDCs to get the same keys.  If each KDC uses a random
   salt, they won't have the same keys.

   *  Random salts may interfere with password history checking.

   *  ktutil's add_entry command assumes the default salt.




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8.2.  Algorithm Rationale

   This document has been written to be consistent with common
   implementations of AES and SHA-2. The  encryption and hash algorithm
   sizes have been chosen to create a consistent level of protection,
   with consideration to implementation efficiencies. So, for instance,
   SHA-384, which would normally be matched to AES-192, is instead
   matched to AES-256 to leverage the fact that there are efficient
   hardware implementations of AES-256. Note that, as indicated by the
   enc-type name "aes256-cts-hmac-sha384-192", the use of SHA-384 and
   AES-256 with a 192-bit key provides only a 192-bit level of security.

9.  Acknowledgements

   Kelley Burgin was employed at the National Security Agency during
   much of the work on this document.

10.  References

10.1.  Normative References

   [RFC2898]    Kaliski, B., "PKCS #5: Password-Based Cryptography
                Specification Version 2.0", RFC 2898, September 2000.

   [RFC3961]    Raeburn, K., "Encryption and Checksum Specifications for
                Kerberos 5", RFC 3961, February 2005.

   [RFC3962]    Raeburn, K., "Advanced Encryption Standard (AES)
                Encryption for Kerberos 5", RFC 3962, February 2005.

   [FIPS197]    National Institute of Standards and Technology,
                "Advanced Encryption Standard (AES)", FIPS PUB 197,
                November 2001.

   [SP800-38A+] National Institute of Standards and Technology,
                "Recommendation for Block Cipher Modes of Operation:
                Three Variants of Ciphertext Stealing for CBC Mode",
                NIST Special Publication 800-38A Addendum, October 2010.

   [SP800-108]  National Institute of Standards and Technology,
                "Recommendation for Key Derivation Using Pseudorandom
                Functions", NIST Special Publication 800-108, October
                2009.

10.2.  Informative References

   [RFC4086]    Eastlake 3rd, D., Schiller, J., and S. Crocker,
                "Randomness Requirements for Security", BCP 106, RFC



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                4086, June 2005.

   [SP800-38A]  National Institute of Standards and Technology,
                "Recommendation for Block Cipher Modes of Operation:
                Methods and Techniques", NIST Special Publication
                800-38A, December 2001.

   [SP800-132]  National Institute of Standards and Technology,
                "Recommendation for Password-Based Key Derivation, Part
                1: Storage Applications", NIST Special Publication 800-
                132, June 2010.

Appendix A.  Test Vectors

   Sample results for string-to-key conversion:
   --------------------------------------------

   Iteration count = 32768
   Pass phrase = "password"
   Saltp for creating 128-bit base-key:
      61 65 73 31 32 38 2D 63 74 73 2D 68 6D 61 63 2D
      73 68 61 32 35 36 2D 31 32 38 00 10 DF 9D D7 83
      E5 BC 8A CE A1 73 0E 74 35 5F 61 41 54 48 45 4E
      41 2E 4D 49 54 2E 45 44 55 72 61 65 62 75 72 6E

   (The saltp is "aes128-cts-hmac-sha256-128" | 0x00 |
    random 16 byte valid UTF-8 sequence | "ATHENA.MIT.EDUraeburn")
   128-bit base-key:
      08 9B CA 48 B1 05 EA 6E A7 7C A5 D2 F3 9D C5 E7

   Saltp for creating 256-bit base-key:
      61 65 73 32 35 36 2D 63 74 73 2D 68 6D 61 63 2D
      73 68 61 33 38 34 2D 31 39 32 00 10 DF 9D D7 83
      E5 BC 8A CE A1 73 0E 74 35 5F 61 41 54 48 45 4E
      41 2E 4D 49 54 2E 45 44 55 72 61 65 62 75 72 6E
   (The saltp is "aes256-cts-hmac-sha384-192" | 0x00 |
    random 16 byte valid UTF-8 sequence | "ATHENA.MIT.EDUraeburn")
   256-bit base-key:
      45 BD 80 6D BF 6A 83 3A 9C FF C1 C9 45 89 A2 22
      36 7A 79 BC 21 C4 13 71 89 06 E9 F5 78 A7 84 67

   Sample results for key derivation:
   ----------------------------------

   enctype aes128-cts-hmac-sha256-128:
   128-bit base-key:
      37 05 D9 60 80 C1 77 28 A0 E8 00 EA B6 E0 D2 3C
   Kc value for key usage 2 (constant = 0x0000000299):



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      B3 1A 01 8A 48 F5 47 76 F4 03 E9 A3 96 32 5D C3
   Ke value for key usage 2 (constant = 0x00000002AA):
      9B 19 7D D1 E8 C5 60 9D 6E 67 C3 E3 7C 62 C7 2E
   Ki value for key usage 2 (constant = 0x0000000255):
      9F DA 0E 56 AB 2D 85 E1 56 9A 68 86 96 C2 6A 6C
   Kp value (constant = 0x707266):
      9C 66 77 98 08 4F 16 82 1E 77 15 DD 5A A6 EB 71

   enctype aes256-cts-hmac-sha384-192:
   256-bit base-key:
      6D 40 4D 37 FA F7 9F 9D F0 D3 35 68 D3 20 66 98
      00 EB 48 36 47 2E A8 A0 26 D1 6B 71 82 46 0C 52
   Kc value for key usage 2 (constant = 0x0000000299):
      EF 57 18 BE 86 CC 84 96 3D 8B BB 50 31 E9 F5 C4
      BA 41 F2 8F AF 69 E7 3D
   Ke value for key usage 2 (constant = 0x00000002AA):
      56 AB 22 BE E6 3D 82 D7 BC 52 27 F6 77 3F 8E A7
      A5 EB 1C 82 51 60 C3 83 12 98 0C 44 2E 5C 7E 49
   Ki value for key usage 2 (constant = 0x0000000255):
      69 B1 65 14 E3 CD 8E 56 B8 20 10 D5 C7 30 12 B6
      22 C4 D0 0F FC 23 ED 1F
   Kp value (constant = 0x707266):
      5D 63 0D B7 EF DE 37 DE 9C 92 03 C5 2B D9 6C 77
      31 BE 1C 5B DD 50 DC 75 44 D9 60 AF F3 CC 23 04

   Sample pseudorandom function (PRF) invocations:
   ----------------------------------------

   PRF input octet-string: "test" (0x74657374)

   enctype aes128-cts-hmac-sha256-128:
   Kp value:
      9C 66 77 98 08 4F 16 82 1E 77 15 DD 5A A6 EB 71
   PRF output:
      3A CA 18 6C C1 26 56 76 5C FE B1 D2 2D 1C B1 36

   enctype aes256-cts-hmac-sha384-192:
   Kp value:
      5D 63 0D B7 EF DE 37 DE 9C 92 03 C5 2B D9 6C 77
      31 BE 1C 5B DD 50 DC 75 44 D9 60 AF F3 CC 23 04
   PRF output:
      01 72 03 F2 90 CD 16 6C D6 B2 BB 4F 18 7D 16 23
      6B 9A 4E D7 66 19 D8 11 6C 64 06 A3 37 E7 F9 08

   Sample encryptions (all using the default cipher state):
   --------------------------------------------------------

   The following test vectors are for



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   enctype aes128-cts-hmac-sha256-128:

   Plaintext: (empty)
   Confounder:
      7E 58 95 EA F2 67 24 35 BA D8 17 F5 45 A3 71 48
   128-bit AES key:
      9B 19 7D D1 E8 C5 60 9D 6E 67 C3 E3 7C 62 C7 2E
   128-bit HMAC key:
      9F DA 0E 56 AB 2D 85 E1 56 9A 68 86 96 C2 6A 6C
   AES Output:
      EF 85 FB 89 0B B8 47 2F 4D AB 20 39 4D CA 78 1D
   Truncated HMAC Output:
      AD 87 7E DA 39 D5 0C 87 0C 0D 5A 0A 8E 48 C7 18
   Ciphertext (AES Output | HMAC Output):
      EF 85 FB 89 0B B8 47 2F 4D AB 20 39 4D CA 78 1D
      AD 87 7E DA 39 D5 0C 87 0C 0D 5A 0A 8E 48 C7 18

   Plaintext: (length less than block size)
      00 01 02 03 04 05
   Confounder:
      7B CA 28 5E 2F D4 13 0F B5 5B 1A 5C 83 BC 5B 24
   128-bit AES key:
      4E FD A6 52 4E 6B 56 B4 F2 12 61 FB FC 93 21 AB
   128-bit HMAC key:
      29 1B 0C 37 73 D7 6E E6 BA 2C CF 1E 03 93 F6 3E
   AES Output:
      AB 70 F4 BA 9D 76 55 AF 24 B5 76 E4 6E FB 7A 98
      F1 4B 93 65 9D 1B
   Truncated HMAC Output:
      A0 C5 F4 7C AA 84 42 19 F9 08 AD ED EF 52 5B 71
   Ciphertext:
      AB 70 F4 BA 9D 76 55 AF 24 B5 76 E4 6E FB 7A 98
      F1 4B 93 65 9D 1B A0 C5 F4 7C AA 84 42 19 F9 08
      AD ED EF 52 5B 71

   Plaintext: (length equals block size)
      00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
   Confounder:
      56 AB 21 71 3F F6 2C 0A 14 57 20 0F 6F A9 94 8F
   128-bit AES key:
      FF 82 40 42 4B CC BA 05 56 50 C0 39 3B 83 DF 3B
   128-bit HMAC key:
      ED 15 62 8B 45 35 8C BF 7F 50 E7 64 C2 6B 8A 1A
   AES Output:
      E7 34 8E 74 86 E5 A7 87 0F 51 2E 65 CA C8 65 75
      78 26 FF C0 EA 5B 28 A8 B9 60 8B B3 08 CD E2 CC
   Truncated HMAC Output:
      C1 85 4E F2 F3 4D 02 35 4E C7 AA 53 BE 03 BE D5



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   Ciphertext:
      E7 34 8E 74 86 E5 A7 87 0F 51 2E 65 CA C8 65 75
      78 26 FF C0 EA 5B 28 A8 B9 60 8B B3 08 CD E2 CC
      C1 85 4E F2 F3 4D 02 35 4E C7 AA 53 BE 03 BE D5

   Plaintext: (length greater than block size)
      00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
      10 11 12 13 14
   Confounder:
      A7 A4 E2 9A 47 28 CE 10 66 4F B6 4E 49 AD 3F AC
   128-bit AES key:
      B5 9B 88 75 AD 5D CA FF F7 79 4D 93 F8 19 9D 79
   128-bit HMAC key:
      0A 42 1D 72 2F 8F C2 D6 84 8B 1C DA D1 5A 49 C9
   AES Output:
      C3 53 72 86 FF 9C FE 49 8D 2E FC FC 99 6D AC 2D
      52 CA 56 03 B3 E8 68 EA 1E 9C 54 E8 2A E5 CE 7A
      79 3E 21 09 7D
   Truncated HMAC Output:
      5B 03 5D 78 A7 E9 84 75 EC 91 0C E3 7A A0 2A 7D
   Ciphertext:
      C3 53 72 86 FF 9C FE 49 8D 2E FC FC 99 6D AC 2D
      52 CA 56 03 B3 E8 68 EA 1E 9C 54 E8 2A E5 CE 7A
      79 3E 21 09 7D 5B 03 5D 78 A7 E9 84 75 EC 91 0C
      E3 7A A0 2A 7D

   The following test vectors are for enctype
   aes256-cts-hmac-sha384-192:

   Plaintext: (empty)
   Confounder:
      F7 64 E9 FA 15 C2 76 47 8B 2C 7D 0C 4E 5F 58 E4
   256-bit AES key:
      0F A2 0D 7D 03 33 EE 65 16 2C DA 67 E7 AD 0D 3C
      5E 03 1F 3B 66 70 E0 31 28 2F AC C2 87 9C 21 C7
   192-bit HMAC key:
      53 BF 30 6A 68 33 A3 25 18 FC B8 5F 63 1D 03 D5
      2E E3 1B 39 75 2F 57 ED
   AES Output:
      FE 6A 55 14 F3 99 7C 8C AA F2 2D 8E EE 28 6D 7D
   Truncated HMAC Output:
      81 1E AD AE DA 7F B9 75 AD 96 C0 07 5A 98 83 F9
      AC 3A AB 06 97 FC E8 5A
   Ciphertext:
      FE 6A 55 14 F3 99 7C 8C AA F2 2D 8E EE 28 6D 7D
      81 1E AD AE DA 7F B9 75 AD 96 C0 07 5A 98 83 F9
      AC 3A AB 06 97 FC E8 5A




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   Plaintext: (length less than block size)
      00 01 02 03 04 05
   Confounder:
      B8 0D 32 51 C1 F6 47 14 94 25 6F FE 71 2D 0B 9A
   256-bit AES key:
      47 DA 4C A2 8B D1 C1 14 D5 50 7E 55 81 86 CA 4F
      DB A0 DA E5 B2 4F 6D 68 89 D5 3A FB F1 D0 B8 36
   192-bit HMAC key:
      13 6B 5C 83 C9 53 AE 29 E2 C2 31 6A 7B 34 B8 C2
      AD 26 E4 66 7F AB 42 6E
   AES Output:
      14 78 CF 26 BA 5E 7D 3A 9D C7 99 7A 80 10 76 2C
      74 3B D4 BC 22 EC
   Truncated HMAC Output:
      17 2A B2 BB 12 B0 0D BE C2 BF E6 29 CF DD 62 EC
      3E 45 83 8F A9 FB AE 6E
   Ciphertext:
      14 78 CF 26 BA 5E 7D 3A 9D C7 99 7A 80 10 76 2C
      74 3B D4 BC 22 EC 17 2A B2 BB 12 B0 0D BE C2 BF
      E6 29 CF DD 62 EC 3E 45 83 8F A9 FB AE 6E

   Plaintext: (length equals block size)
      00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
   Confounder:
      53 BF 8A 0D 10 52 65 D4 E2 76 42 86 24 CE 5E 63
   256-bit AES key:
      5E A6 16 D8 FD A2 33 F1 B4 99 79 A4 B9 FA 01 D3
      21 B1 3D 6F BD 6E 3B B7 2E 54 B4 85 E2 36 AF 23
   192-bit HMAC key:
      AD D3 8D C9 86 83 C5 CC 14 E3 C7 37 EA A7 06 47
      B3 19 71 0E 87 6A 38 77
   AES Output:
      B6 0B 6A A6 00 C2 D8 4B 03 A6 1C 18 DD A7 05 F0
      FE 90 B9 36 B8 8C 4F EA 06 D7 1A 99 35 75 28 60
   Truncated HMAC Output:
      2F E5 BD 6E 41 78 17 D6 2A D2 C9 CF 50 8D FA E1
      B3 C9 6F 4B 45 C1 9B 77
   Ciphertext:
      B6 0B 6A A6 00 C2 D8 4B 03 A6 1C 18 DD A7 05 F0
      FE 90 B9 36 B8 8C 4F EA 06 D7 1A 99 35 75 28 60
      2F E5 BD 6E 41 78 17 D6 2A D2 C9 CF 50 8D FA E1
      B3 C9 6F 4B 45 C1 9B 77

   Plaintext: (length greater than block size)
      00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
      10 11 12 13 14
   Confounder:
      76 3E 65 36 7E 86 4F 02 F5 51 53 C7 E3 B5 8A F1



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   256-bit AES key:
      B3 A8 02 E3 40 61 3E F1 E0 EC E9 1A 15 7C 59 12
      6F BD C4 B8 C2 4C 8D 0B 2E 5A 30 F0 1E 7E 34 88
   192-bit HMAC key:
      FC 0B 49 9B 83 55 A3 2A C3 C9 AC B6 64 93 63 EB
      5D BB A4 25 1A 75 B2 0A
   AES Output:
      4C F9 8B 5E DA 0D 94 9F B3 8E CD 67 DE 80 0F 79
      46 19 F9 EA CB 30 54 33 50 6B 9A D4 48 4B D9 5B
      E0 55 F5 69 EB
   Truncated HMAC Output:
      7C F8 36 70 75 8C BF DA 31 3C FE F8 74 2B 11 74
      14 A7 DD 12 B4 96 64 2E
   Ciphertext:
      4C F9 8B 5E DA 0D 94 9F B3 8E CD 67 DE 80 0F 79
      46 19 F9 EA CB 30 54 33 50 6B 9A D4 48 4B D9 5B
      E0 55 F5 69 EB 7C F8 36 70 75 8C BF DA 31 3C FE
      F8 74 2B 11 74 14 A7 DD 12 B4 96 64 2E


   Sample checksums:
   -----------------

   Checksum type: hmac-sha256-128-aes128
   128-bit HMAC key:
      B3 1A 01 8A 48 F5 47 76 F4 03 E9 A3 96 32 5D C3
   Plaintext:
      00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
      10 11 12 13 14
   Checksum:
      D7 83 67 18 66 43 D6 7B 41 1C BA 91 39 FC 1D EE

   Checksum type: hmac-sha384-192-aes256
   192-bit HMAC key:
      EF 57 18 BE 86 CC 84 96 3D 8B BB 50 31 E9 F5 C4
      BA 41 F2 8F AF 69 E7 3D
   Plaintext:
      00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
      10 11 12 13 14
   Checksum:
      45 EE 79 15 67 EE FC A3 7F 4A C1 E0 22 2D E8 0D
      43 C3 BF A0 66 99 67 2A









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Authors' Addresses

   Michael J. Jenkins
   National Security Agency

   EMail: mjjenki@tycho.ncsc.mil

   Michael A. Peck
   The MITRE Corporation

   EMail: mpeck@mitre.org

   Kelley W. Burgin

   Email: kelley.burgin@gmail.com




































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