Network Working Group M. Jenkins
Internet Draft National Security Agency
Intended Status: Informational M. Peck
Expires: November 7, 2014 The MITRE Corporation
K. Burgin
May 6, 2014
AES Encryption with HMAC-SHA2 for Kerberos 5
draft-ietf-kitten-aes-cts-hmac-sha2-02
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
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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 . . . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 7
8.1. Random Values in Salt Strings . . . . . . . . . . . . . . 7
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. Test Vectors . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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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. The counter i is expressed
as four octets in big-endian order. The length of the output key in
bits (denoted as k) is also represented as four octets in big-endian
order. The "Label" input to the KDF is the usage constant supplied
to the key derivation function, and the "Context" input is null.
Each application of the KDF only requires a single iteration of the
PRF, so n = 1 in the notation of [SP800-108].
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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) and Ke, and 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) or Ke (the constant ends with 0xAA):
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,
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}.
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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 }.
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)
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Ki = KDF-HMAC-SHA2(base-key, usage | 0x55)
cipherstate: a 128-bit CBC initialization vector.
initial cipherstate: all bits zero.
encryption function: as follows, where E() is AES encryption in
CBC-CS3 mode, h is the size of truncated HMAC, and c is the AES
block size.
N = random nonce of length c (128 bits)
IV = cipherstate
C = E(Ke, N | plaintext, IV)
H = HMAC(Ki, IV | C)
ciphertext = C | H[1..h]
cipherstate = next-to-last 128-bit block of C
Note: if C is only a single block, then cipherstate = C
decryption function: as follows, where D() is AES encryption 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.
cipherstate = next-to-last 128-bit block of C
Note: if C is only a single block, then cipherstate = C
pseudo-random function:
Kp = KDF-HMAC-SHA2(protocol-key, "prf")
PRF = HMAC(Kp, octet-string)
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.
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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.
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 the salt used as
input to the PBKDF to contain at least 128 bits of random. Some
known issues with including random values in Kerberos encryption type
salt strings are:
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* Cross-realm TGTs are currently 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.
* 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.
* Current implementations of password history checking will not
work.
* ktutil's add_entry command assumes the default salt.
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,
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"Randomness Requirements for Security", BCP 106, RFC
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
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Kc value for key usage 2 (constant = 0x0000000299):
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
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
Sample encryptions (all using the default cipher state):
----------------------------------------------------
The following test vectors are for
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
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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
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
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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
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
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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
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:
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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
Jenkins, et al. Expires November 7, 2014 [Page 14]
Internet-Draft AES-CTS HMAC-SHA2 For Kerberos 5 May 6, 2014
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
Jenkins, et al. Expires November 7, 2014 [Page 15]