Network Working Group~~K. Burgin~~M. JenkinsInternet Draft National Security Agency Intended Status: Informational M. Peck Expires:~~December 30, 2013~~November 7, 2014The MITRE Corporation~~June 28, 2013~~K. Burgin May 6, 2014AES Encryption with HMAC-SHA2 for Kerberos 5~~draft-ietf-kitten-aes-cts-hmac-sha2-01~~draft-ietf-kitten-aes-cts-hmac-sha2-02Abstract 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 Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- 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~~December 30, 2013.~~January 20, 2014.Copyright and License Notice Copyright (c)~~2013~~2014IETF 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Protocol Key Representation . . . . . . . . . . . . . . . . . 3 3. Key~~Generation from Pass Phrases~~Derivation Function. . . . . . . . . . . . . . .~~3 4. Key Derivation Function~~. . . .3 4. Key Generation from Pass Phrases. . . . . . . . . . . . . . . 4 5. Kerberos Algorithm Protocol Parameters . . . . . . . . . . . . 5 6. Checksum Parameters . . . . . . . . . . . . . . . . . . . . .~~8~~67. IANA Considerations . . . . . . . . . . . . . . . . . . . . .~~9~~78. Security Considerations . . . . . . . . . . . . . . . . . . .~~9~~78.1. Random Values in Salt Strings . . . . . . . . . . . . . .~~9~~79.~~References~~Acknowledgements. . . . . . . . . . . . . . . . . . . . . . .8 10. References. . .~~10 9.1.~~. . . . . . . . . . . . . . . . . . . . . . 8 10.1.Normative References . . . . . . . . . . . . . . . . . .~~. 10 9.2.~~8 10.2.Informative References . . . . . . . . . . . . . . . . .~~. 10~~8Appendix A. Test Vectors . . . . . . . . . . . . . . . . . . . .~~11~~9Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 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 usea variation ofthe CBC-CS3~~variant to CBC~~mode defined in~~[SP800-38A+] (this mode is~~[SP800-38A+],also referred to as~~CTS).~~ciphertext stealing or CTS mode.The new types conform to the framework specified in [RFC3961], but do not use the simplified profile.~~Note that [SP800-38A+] requires the plaintext length to be greater than the block size, so the encryption types have two cases.~~The encryption and checksum types defined in this document are intended to support~~NSA's Suite B Profile for Kerberos [suiteb- kerberos] which requires the~~environments that desire touse~~of~~SHA-256 or~~SHA-384~~SHA- 384as the hash algorithm. Differences between the encryption and checksum types defined in this document and~~existing~~the pre-existingKerberosAESencryption and checksum typesspecified in [RFC3962]are: * The pseudorandom function used by PBKDF2 is HMAC-SHA-256 or HMAC- SHA-384. * A key derivation function from [SP800-108]~~which uses~~usingthe SHA-256 or SHA-384 hash algorithm is used to produce keys for encryption, integrity protection, and checksum operations. * The~~IV used during content encryption is sent as part of the ciphertext, instead of using a confounder. This saves one encryption and decryption operation per message. * The~~HMAC is calculated over thecipherstate concatenated with theAES output, instead of being calculated over theconfounder andplaintext. 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~~Generation from Pass Phrases The pseudorandom~~Derivation Function We use a key derivationfunction~~used by PBKDF2 will be the SHA-256 or SHA- 384 HMAC~~from Section 5.1of[SP800-108] which usesthe~~passphrase and salt. If the enctype is "aes128-cts- hmac-sha256-128", then HMAC-SHA-256 is used~~HMAC algorithmas the PRF.~~If the enctype is "aes256-cts-hmac-sha384-192", then HMAC-SHA-384~~The counter iis~~used~~expressedas~~the PRF.~~four octets in big-endian order.The~~final key derivation step uses~~length ofthe~~algorithm KDF-HMAC-SHA2 defined below~~output keyin~~Section 4. If no string-to-key parameters are specified, the default number of iterations~~bits (denoted as k)is~~raised to 32,768. To ensure that different long-term keys are used with different enctypes, we prepend the enctype name to the salt string, 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 key is derived as follows saltp = enctype-name | 0x00 | salt tkey = random-to-key(PBKDF2(passphrase, saltp, iter_count, keylength)) 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, and the algorithm KDF-HMAC-SHA2 is defined in Section 4. 4. 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~~also represented as four octets in big-endian order. The "Label" inputto 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]. In the following summary, | indicates concatenation. The random-to- key function is the identity~~function, as defined in Section 3.~~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 |~~0x00~~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~~computing~~derivingthe 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,~~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 |~~0x00~~00| 00 00 00 C0) KDF-HMAC-SHA2(key, constant) = random-to-key(k-truncate(K1))~~Otherwise (if deriving Ke or~~Ifderiving the base-key~~from a passphrase as described in Section 3):~~(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 |~~0x00~~00| 00 00 01 00) KDF-HMAC-SHA2(key, constant) = random-to-key(k-truncate(K1))~~The constants~~4. Key Generation from Pass Phrases PBKDF2 [RFC2898] isused~~for key derivation~~to derive the base-key from a passphrase and salt. If no string-to-key parametersarespecified,the~~same as those~~default number of iterations is 32,768. To ensure that different long-term base-keys areused~~in~~with different enctypes, we prependthe~~simplified profile. 5. Kerberos Algorithm Protocol Parameters In cases where~~enctype name tothe~~plaintext length~~salt, separated by a null byte. The enctype-nameis~~greater than~~"aes128-cts-hmac- sha256-128" or "aes256-cts-hmac-sha384-192" (withoutthe~~block size: Each encryption will use a 16-octet nonce generated at random~~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 usedbyPBKDF2 is HMAC-SHA-256 whenthe~~message originator.~~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 ParametersThecipherstate is used as the formalinitialization vector (IV)~~used by AES~~input into CBC-CS3. The plaintextis~~obtained by xoring the~~prepended with a 16-octetrandom nonce~~with~~generated bythe~~cipherstate.~~message originator, known as a confounder.The ciphertext is~~the~~aconcatenation of the~~random nonce, the~~output of AES in CBC-CS3~~mode,~~modeand the HMAC of the~~nonce~~cipherstateconcatenated with the AES output. The HMAC is computed using either SHA-256 or~~SHA-384.~~SHA-384 depending on the encryption type.The output of~~SHA-256~~HMAC-SHA-256is truncated to 128 bits and the output of~~SHA-384~~HMAC-SHA-384is truncated to 192 bits. Sample test vectors are given in Appendix A. Decryption is performed by removing the HMAC, verifying the HMAC against the~~remainder,~~cipherstate concatenated with the ciphertext,and then decrypting the~~remainder~~ciphertextif the HMAC is correct.~~In cases where the plaintext length is less than or equal to the block size, a different algorithm is specified. Each encryption will use a 16-octet nonce generated at random by the message originator. The initialization vector (IV) used by AES is obtained by xoring~~Finally,the~~random nonce with~~first 16 octets ofthe~~cipherstate. The plaintext~~decryption output (the confounder)is~~padded with zeros so the length of~~discarded, andthe~~result~~remainderis~~one block length (no zeros are added if~~returned asthe plaintext~~length equals the block length).~~decryption output.The~~padded plaintext is xored with~~following parameters apply tothe~~IV, then encrypted using AES in ECB mode. The output of AES is split into two parts, so that the length of the first part equals the length of the unpadded plaintext. The nonce is also split into two parts, so that the length of the first part equals the length of the unpadded plaintext. The ciphertext is the concatenation of the first part of the random nonce, the second part of the AES output followed by the first part of the AES output, and the HMAC of the concatenation of the first part of the random nonce, the second part of the AES output followed by the first part of the AES output. The HMAC is computed using either SHA-256 or SHA-384. The output of SHA-256 is truncated to 128 bits and the output of SHA-384 is truncated to 192 bits. Sample test vectors are given in Appendix A. Decryption is performed by first removing the HMAC, and verifying the HMAC against the remainder. If the HMAC is correct, separate the remainder into N' and C' by taking the first 16 bytes as N', and the following bytes as C'. Split N' into two parts, so that the length of the first part equals the length of C'. Decrypt the concatenation of C' with the second part of N' using ECB mode to get a value P' whose length is one block length. The nonce is recovered by taking the concatenation of the first part of N' with the second part of P' xored with the cipherState (where again, the length of the first part equals the length of C'). The IV is recovered as the nonce xored with cipherState, and the plaintext is recovered as the first part of P' xored with the IV. The following parameters apply to the encryption types aes128-cts- hmac-sha256-128 and aes256-cts-hmac-sha384-192. protocol key format: as defined~~encryption types aes128-cts- hmac-sha256-128 and aes256-cts-hmac-sha384-192. protocol key format: as definedin 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~~3.~~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~~4.~~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:~~cipherstate:a 128-bit~~random nonce.~~CBC initialization vector.initial~~cipherState:~~cipherstate:all bits zero. encryption function: as~~follows. When the plaintext length is greater than the block size, CTS mode~~follows, where E()is~~used. When the plaintext~~AES encryption in CBC-CS3 mode, his~~less than or equal to~~the~~block size, ECB mode is used. h =~~size of truncated~~HMAC E() = encryption function D() = decryption function~~HMAC, andc~~= block size of~~isthe~~encryption algorithm L(x) = length of x < = less-than operator; true == 1, false == 0 zeroblock = one~~AESblock~~(length c) of zeros o[start:len] = sub-string operation returning the substring of length len of string o starting at byte start (zero-based) encryption function:~~size.N = random nonce of length~~128 bits~~c (128 bits)IV =~~N XOR cipherState if (L(P) > c) PC = 0 P' = P~~cipherstateC = E(Ke,~~P', IV) // using CBC-CS3-Encrypt defined // in [SP800-38A+] N' =~~N~~C' = C else PC = c - L(P) P' = P~~|~~zeroblock[0:PC] C = E(Ke, P' XOR~~plaintext,IV)~~// using ECB mode N' = N[0:c - PC] | C[c - PC:PC] C' = C[0:c - PC]~~H = HMAC(Ki,~~N'~~IV|~~C')~~C)ciphertext =~~N' | C'~~C| H[1..h]~~cipherState~~cipherstate=~~N~~next-to-last 128-bit block of C Note: if C is only a single block, then cipherstate = Cdecryption function:~~(N', C',~~as follows, where D() is AES encryption in CBC-CS3 mode, and h is the size of truncated HMAC. (C,H) = ciphertextIV = cipherstateif~~(H~~H!= HMAC(Ki,~~N'~~IV|~~C')[1..h])~~C)[1..h]stop, report error~~if (L(C') > c) // Not short-plaintext IV = N' XOR cipherState P~~(N, P)= D(Ke,~~C',~~C,IV)~~// using CBC-CS3-Decrypt defined // in [SP800-38A+] cipherState = N' stop, output P, success else // Short plaintext PC = c - L(C') C = C' | N'[c - PC:PC] P' = D(Ke, C) // using ECB mode // P' here == (P | zeroblock[0:PC]) XOR IV // so IV[c - PC:PC] == P'[c - PC:PC] // In the non-short-pt case we'd recover // IV as N XOR cipherState, but here we only know // a head of~~Note:N~~and tail~~is set to the first blockof~~IV. N = N'[0:c -PC] | (P' XOR cipherState)[c - PC:PC] IV = N XOR cipherState~~the decryption output,Pis set to the rest of the output. cipherstate=~~(P' XOR IV)[0:PC] cipherState~~next-to-last 128-bit block of C Note: if C is only a single block, then cipherstate=~~N stop, output P, success~~Cpseudo-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~~appropriate.get_mic: HMAC(Kc,~~message)[1..h]~~message)[1..h].verify_mic: get_mic and~~compare~~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. 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.~~NIST Special Publication 800-90 [SP800-90] and~~[RFC4086]~~offer~~offersrandom 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: * 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~~9.1.~~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.~~[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, "Randomness Requirements~~[RFC3962] Raeburn, K., "Advanced Encryption Standard (AES) Encryptionfor~~Security", BCP 106,~~Kerberos 5",RFC~~4086, June~~3962, February2005. [FIPS197] National Institute of Standards and Technology, "Advanced Encryption Standard (AES)", FIPS PUB 197, November 2001.~~9.2. Informative References~~[SP800-38A+] National Institute of Standards and Technology, "Recommendation for Block Cipher Modes of Operation: Three Variants of Ciphertext Stealing for CBC Mode",~~Addendum to~~NIST Special Publication~~800-38A,~~800-38A Addendum,October 2010.~~[SP800-90]~~[SP800-108]National Institute of Standards and Technology,~~Recommendation~~"Recommendationfor~~Random Number Generation~~Key DerivationUsing~~Deterministic Random Bit Generators (Revised),~~Pseudorandom Functions",NIST Special Publication~~800-90, March 2007. [SP800-108]~~800-108, October 2009. 10.2. Informative References [RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", BCP 106, RFC 4086, June 2005. [SP800-38A]National Institute of Standards and Technology, "Recommendation for~~Key Derivation Using Pseudorandom Functions",~~Block Cipher Modes of Operation: Methods and Techniques",NIST Special Publication~~800-108, October 2009.~~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.~~[suiteb-kerberos] Burgin, K. and K. Igoe, "Suite B Profile for Kerberos 5", internet-draft draft-burgin-kerberos- suiteb-01, 2012.~~Appendix A. Test Vectors Sample results for string-to-key conversion: -------------------------------------------- Iteration count = 32768 Pass phrase = "password" Saltp for creating 128-bit~~master key:~~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~~master key: 3C 44 03 85 28 06 BF 5C EE E6 36~~base-key: 08 9B CA48~~6C 29 2F D6~~B1 05 EA 6E A7 7C A5 D2 F3 9D C5 E7Saltp for creating 256-bit~~master key:~~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~~master key: 53 96 0C AF 44 D5 57 4D~~base-key: 45 BD 80 6D BF 6A 83 3A 9CFF~~4D 44 37 38 75~~C1 C9 45 89 A222~~B0 7F 5B 02 5C 5E 65 BF EF 29 C2 B4 28 98 3B 37 08~~36 7A 79 BC 21 C4 13 71 89 06 E9 F5 78 A7 84 67Sample results for key derivation: ---------------------------------- enctype aes128-cts-hmac-sha256-128: 128-bit~~master key:~~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): 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~~master key:~~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~~(using~~(all usingthe default cipher state): ----------------------------------------------------~~128-bit AES key: 2B 7E 15 16 28 AE D2 A6 AB F7 15 88 09 CF 4F 3C 128-bit HMAC key: 67 C3 31 A4 D7 AB 52 EF 3A A9 73 E0 39 AD D3 32 Nonce:~~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~~Plaintext: (length less than block size) 49 6E 63 6F~~128-bit AES key: 9B 19 7D D1 E8 C5 60 9D6E~~63 65 69 76 61~~67 C3 E3 7C62C7 2E 128-bit HMAC key: 9F DA 0E 56 AB 2D 85 E1 56 9A 68 86 96 C2 6A6C~~65~~AES Output:~~1C 17 3E AD FC 67 C8 BC B3 A5 93 02 98 CB FC 60 HMAC Output (truncated): 35 E8 32 B2 EB F4 6A 46 C2 E6 50 D2 50~~EF 85 FB 89 0B B8 47 2F 4DAB~~84 43 Ciphertext: (Nonce* | AES Output** |~~20 39 4D CA 78 1DTruncated HMAC~~Output) 7E 58 95 EA F2 67 24 35 BA D8 17 F5 45 CB FC 60 1C 17 3E~~Output:AD~~FC 67 C8 BC B3 A5 93 02 98 35 E8 32 B2 EB F4 6A 46 C2 E6 50 D2 50 AB 84 43 * Only the first 13 bytes of Nonce are sent. ** The AES~~87 7E DA 39 D5 0C 87 0C 0D 5A 0A 8E 48 C7 18 Ciphertext (AESOutput~~is split and rearranged as described in Section 5 since the plaintext length is~~| 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: (lengthless than~~the~~block~~size.~~size) 00 01 02 03 04 05 Confounder: 7B CA 28 5E 2F D4 13 0F B5 5B 1A 5C 83 BC 5B 24128-bit AES key:~~2B 7E 15 16 28 AE D2~~4E FDA652 4E 6B 56 B4 F2 12 61 FB FC 93 21AB~~F7 15 88 09 CF 4F 3C~~128-bit HMAC key:~~67 C3 31 A4~~29 1B 0C 37 73D76E E6 BA 2C CF 1E 03 93 F6 3E AES Output:AB~~52 EF 3A A9 73 E0 39 AD D3 32 Nonce: 7E 58 95 EA F2 67 24 35~~70 F4BA~~D8 17 F5 45 A3 71 48 Plaintext: (length equals block size) 67 61 73 74 72 6F 69 6E 74 65 73 74 69~~9D 76 55 AF 24 B5 76 E46E~~61 6C AES Output: F6 71 0B 75 0C 60~~FB 7A 98 F1 4B 9365~~E8 2E BF F8~~9D~~DC E0 C9 B9~~1B TruncatedHMAC~~Output (truncated): 7B 2C D9 70 E6 DF 18 F5 E0 3D 8B 8E 40 02~~Output: A0 C5F4~~C0~~7C AA 84 42 19 F9 08 AD ED EF 52 5B 71Ciphertext:~~(Nonce | AES Output | Truncated HMAC Output) 7E 58 95 EA F2 67 24 35~~AB 70 F4BA~~D8 17 F5 45 A3 71 48 F6 71 0B 75 0C 60~~9D 76 55 AF 24 B5 76 E4 6E FB 7A 98 F1 4B 9365~~E8 2E BF F8~~9D~~DC E0 C9 B9 7B 2C D9 70 E6 DF 18 F5 E0 3D 8B 8E 40 02~~1B A0 C5F4~~C0 256-bit AES key: 60 3D EB 10 15 CA~~7C AA 84 42 19 F9 08 AD ED EF 52 5B71~~BE 2B 73 AE F0 85 7D 77 81 1F 35 2C~~Plaintext: (length equals block size) 00 01 02 03 04 05 0607~~3B 61~~08~~D7 2D 98 10 A3~~090A 0B 0C 0D 0E 0F Confounder: 56 AB 21 71 3F F6 2C 0A1457 20 0F 6F A9 94 8F 128-bit AES key: FF 82 40 42 4B CC BA 05 56 50 C0 39 3B 83DF~~F4 192-bit~~3B 128-bitHMAC key:~~37 16 14 EB 62 24 E1 F0 C4 72 6E E6 BE A7 A3 D2 F4~~ED 1562~~C6 AC 66 42 A6 AC Nonce: 7E 58 95 EA F2 67 24 35 BA D8 17 F5~~8B45~~A3 71 48 Plaintext: (length less than block size) 49 6E 63 6F 6E 63 65 69 76 61 62 6C 65~~35 8C BF 7F 50 E7 64 C2 6B 8A 1AAES Output:~~BD AE EC 5C F9 C9 B6 3C 9D DB A2 B7 9D 5C 6C 0B HMAC Output (truncated): 65 D4 C7 07~~E7 348E~~14~~74 86 E5 A7 87 0F 51 2E 65 CA C86575 78 26 FF C0 EA 5B 28 A8 B9 608B~~C9~~B3~~C4 EA F5 F7 C2 6F ED 36 AC 7A~~08CD~~59 19 2B Ciphertext: (Nonce* | AES Output* |~~E2 CCTruncated HMAC~~Output) 7E 58 95 EA~~Output: C1 85 4EF2~~67 24~~F3 4D 0235~~BA D8 17 F5 45 5C 6C 0B BD AE EC 5C F9 C9 B6 3C 9D DB A2 B7 9D 65 D4~~4EC7~~07~~AA 53 BE 03 BE D5 Ciphertext: E7 348E~~14~~74 86 E5 A7 87 0F 51 2E 65 CA C86575 78 26 FF C0 EA 5B 28 A8 B9 608B~~C9~~B3~~C4 EA F5 F7 C2 6F ED 36 AC 7A~~08CD~~59 19 2B * Only the first 13 bytes of Nonce are sent. ** The AES Output is split and rearranged as described in Section 5 since the plaintext length is less~~E2 CC C1 85 4E F2 F3 4D 02 35 4E C7 AA 53 BE 03 BE D5 Plaintext: (length greaterthan~~the~~block~~size. 256-bit AES key: 60 3D EB~~size) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F10~~15 CA 71 BE 2B 73~~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 ADAE~~F0 85~~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 6D7D~~77~~81~~1F 35 2C~~1E AD AE DA 7F B9 75 AD 96 C007~~3B 61 08 D7~~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 712D~~98 10 A3 09~~0B 9A 256-bit AES key: 47 DA 4C A2 8B D1 C114~~DF F4~~D5 50 7E 55 81 86 CA 4F DB A0 DA E5 B2 4F 6D 68 89 D5 3A FB F1 D0 B8 36192-bit HMAC key:~~37 16 14 EB 62 24 E1 F0 C4 72 6E E6 BE A7 A3 D2 F4 62 C6 AC~~13 6B 5C 83 C9 53 AE 29 E2 C2 31 6A 7B 34 B8 C2 AD 26 E4667F AB42~~A6 AC Nonce: 7E 58 95 EA F2 67 24 35 BA D8 17 F5 45 A3 71 48 Plaintext: (length equals block size) 67 61 73 74 72 6F 69 6E 74 65 73 74 69~~6E~~61 6C~~AES Output:~~5D E5 49 BE D6 50 23 18 78 8F~~14~~D2 E1 17 E0 5A HMAC Output (truncated):~~78 CF 26 BA 5E 7D 3A 9D C7 99 7A 80 10 762C~~EA DF D5 B0 60 38 DE A9~~74 3B D4 BC22~~29 2D 7C 56 50 10 C5 D6 D2 8D F6 21 E9 7A Ciphertext: (Nonce | AES Output |~~ECTruncated HMAC~~Output) 7E 58 95 EA F2 67 24 35 BA D8 17 F5 45 A3 71 48 5D E5 49 BE D6 50 23 18 78 8F 14 D2 E1~~Output:17~~E0 5A 2C EA DF D5~~2A B2 BB 12B0~~60 38 DE A9 22~~0D BE C2 BF E629~~2D 7C 56 50 10 C5 D6 D2 8D F6 21 E9 7A 128-bit AES key: 9B 19~~CF DD 62 EC 3E 45 83 8F A9 FB AE 6E Ciphertext: 14 78 CF 26 BA 5E7D~~D1 E8 C5 60~~3A9D~~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 Nonce: 8D 32 50 F6 36 AB 81 02 BE 6F AB 1E 57 D8 F8~~99 7A 80 10 76 2C 74 3B D4 BC 22 EC172A B2 BB 12 B0 0D BE C2 BF E6 29 CF DD 62 EC 3E 45 83 8F A9 FB AE 6EPlaintext: (length~~greater than the~~equalsblock size) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0FConfounder: 53 BF 8A 0D10~~11 12 13 14 AES Output: 13 64 FB 39 DC C0 E3 D9 83 A7 DB 5B 4B 9F FB CA 42 F6~~5265~~88 29 HMAC Output (truncated): F2 1F C8 95 75 AE 93 C7 57 18 AB 3C 7C FB 28 E1 Ciphertext: (Nonce | AES Output | HMAC Output) 8D 32 50 F6 36 AB 81 02 BE 6F AB 1E 57 D8 F8 17 13 64 FB 39 DC C0 E3 D9 83 A7 DB 5B 4B 9F FB CA~~D4 E2 7642~~F6 65 88 29 F2 1F C8 95 75 AE 93 C7 57 18 AB 3C 7C FB 28 E1~~86 24 CE 5E 63256-bit AES key:~~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~~5E A6 16 D8 FD A2 33 F1 B4 99 79 A4 B9 FA 01 D3 21 B1 3D 6F BD 6E 3B B72E~~5C 7E 49~~54 B4 85 E2 36 AF 23192-bit HMAC key:~~69 B1 65~~AD D3 8D C9 86 83 C5 CC14 E3~~CD 8E 56 B8 20 10 D5~~C7~~30 12~~37 EA A7 06 47 B3 19 71 0E 87 6A 38 77 AES Output:B6~~22 C4 D0 0F FC 23 ED 1F Nonce: 8D 32 50 F6~~0B 6A A6 00 C2 D8 4B 03 A6 1C 18 DD A7 05 F0 FE 90 B936~~AB 81 02 BE~~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 C96F~~AB 1E 57~~4B 45 C1 9B 77 Ciphertext: B6 0B 6A A6 00 C2D8~~F8~~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 7817D6 2A D2 C9 CF 50 8D FA E1 B3 C9 6F 4B 45 C1 9B 77Plaintext: (length greater than~~the~~block size) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 13 14Confounder: 76 3E 65 36 7E 86 4F 02 F5 51 53 C7 E3 B5 8A F1 256-bitAES~~Output: 50 CB FF DC DF 38 69 D7~~key: B3 A8 02 E3 40 61 3E F1 E0 EC E9 1A 15 7C 59 12 6F BD C4 B8 C2 4C 8D0B~~EA FF C3 2C 47~~2E 5A 30 F0 1E 7E 34 88 192-bit HMAC key: FC0B~~C6 5B 72~~49 9B 83 55 A3 2AC3~~37 2D HMAC Output (truncated): 6E D7~~C9 AC B6 64 93 63 EB 5D BB A4 25 1A 75 B2 0A AES Output: 4C F9 8B 5E DA 0D 94 9FB3~~47 E9 0B BD 8F 31 F5~~8E CD 67 DE 80 0F79~~58~~46 19F9~~69~~EA CB 30 54 3350~~BA A1 41 64 6E 65 6C F6 7C Ciphertext: (Nonce | AES Output |~~6B 9A D4 48 4B D9 5B E0 55 F5 69 EB TruncatedHMAC~~Output) 8D 32 50 F6~~Output: 7C F836~~AB 81 02 BE 6F AB 1E 57 D8~~70 75 8C BF DA 31 3C FEF8~~17 50 CB FF DC DF 38 69 D7 0B EA FF C3 2C 47 0B C6 5B 72 C3 37 2D 6E D7~~74 2B 11 74 14 A7 DD 12 B4 96 64 2E Ciphertext: 4C F9 8B 5E DA 0D 94 9FB3~~47 E9 0B BD 8F 31 F5~~8E CD 67 DE 80 0F79~~58~~46 19F9~~69~~EA CB 30 54 3350~~BA A1 41 64 6E 65 6C F6~~6B 9A D4 48 4B D9 5B E0 55 F5 69 EB7CF8 36 70 75 8C BF DA 31 3C FE F8 74 2B 11 74 14 A7 DD 12 B4 96 64 2ESample checksums: ----------------- Checksum type: hmac-sha256-128-aes128 128-bit~~master key: 37 05 D9 60 80 C1 77 28 A0 E8 00 EA B6 E0 D2 3C 128-bit~~HMAC~~key (Kc, key usage 2):~~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~~256-bit master 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~~192-bit HMAC~~key (Kc, key usage 2):~~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 Authors' Addresses~~Kelley W. Burgin~~Michael J. JenkinsNational Security Agency EMail:~~kwburgi@tycho.ncsc.mil~~mjjenki@tycho.ncsc.milMichael A. Peck The MITRE Corporation EMail: mpeck@mitre.orgKelley W. Burgin Email: kelley.burgin@gmail.com