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diff --git a/doc/rfc/rfc3962.txt b/doc/rfc/rfc3962.txt new file mode 100644 index 0000000..762beed --- /dev/null +++ b/doc/rfc/rfc3962.txt @@ -0,0 +1,899 @@ + + + + + + +Network Working Group K. Raeburn +Request for Comments: 3962 MIT +Category: Standards Track February 2005 + + + Advanced Encryption Standard (AES) Encryption for Kerberos 5 + +Status of This Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (C) The Internet Society (2005). + +Abstract + + The United States National Institute of Standards and Technology + (NIST) has chosen a new Advanced Encryption Standard (AES), which is + significantly faster and (it is believed) more secure than the old + Data Encryption Standard (DES) algorithm. This document is a + specification for the addition of this algorithm to the Kerberos + cryptosystem suite. + +1. Introduction + + This document defines encryption key and checksum types for Kerberos + 5 using the AES algorithm recently chosen by NIST. These new types + support 128-bit block encryption and key sizes of 128 or 256 bits. + + Using the "simplified profile" of [KCRYPTO], we can define a pair of + encryption and checksum schemes. AES is used with ciphertext + stealing to avoid message expansion, and SHA-1 [SHA1] is the + associated checksum function. + +2. Conventions used in this Document + + 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 BCP 14, RFC 2119 + [KEYWORDS]. + + + + + + +Raeburn Standards Track [Page 1] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + +3. Protocol Key Representation + + The profile in [KCRYPTO] treats keys and random octet strings as + conceptually different. But since the AES key space is dense, we can + use any bit string of appropriate length as a key. We use the byte + representation for the key described in [AES], where the first bit of + the bit string is the high bit of the first byte of the byte string + (octet string) representation. + +4. Key Generation from Pass Phrases or Random Data + + Given the above format for keys, we can generate keys from the + appropriate amounts of random data (128 or 256 bits) by simply + copying the input string. + + To generate an encryption key from a pass phrase and salt string, we + use the PBKDF2 function from PKCS #5 v2.0 ([PKCS5]), with parameters + indicated below, to generate an intermediate key (of the same length + as the desired final key), which is then passed into the DK function + with the 8-octet ASCII string "kerberos" as is done for des3-cbc- + hmac-sha1-kd in [KCRYPTO]. (In [KCRYPTO] terms, the PBKDF2 function + produces a "random octet string", hence the application of the + random-to-key function even though it's effectively a simple identity + operation.) The resulting key is the user's long-term key for use + with the encryption algorithm in question. + + tkey = random2key(PBKDF2(passphrase, salt, iter_count, keylength)) + key = DK(tkey, "kerberos") + + The pseudorandom function used by PBKDF2 will be a SHA-1 HMAC of the + passphrase and salt, as described in Appendix B.1 to PKCS#5. + + The number of iterations is specified by the string-to-key parameters + supplied. The parameter string is four octets indicating an unsigned + number in big-endian order. This is the number of iterations to be + performed. If the value is 00 00 00 00, the number of iterations to + be performed is 4,294,967,296 (2**32). (Thus the minimum expressible + iteration count is 1.) + + For environments where slower hardware is the norm, implementations + of protocols such as Kerberos may wish to limit the number of + iterations to prevent a spoofed response supplied by an attacker from + consuming lots of client-side CPU time; if such a limit is + implemented, it SHOULD be no less than 50,000. Even for environments + with fast hardware, 4 billion iterations is likely to take a fairly + long time; much larger bounds might still be enforced, and it might + be wise for implementations to permit interruption of this operation + by the user if the environment allows for it. + + + +Raeburn Standards Track [Page 2] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + If the string-to-key parameters are not supplied, the value used is + 00 00 10 00 (decimal 4,096, indicating 4,096 iterations). + + Note that this is not a requirement, nor even a recommendation, for + this value to be used in "optimistic preauthentication" (e.g., + attempting timestamp-based preauthentication using the user's long- + term key without having first communicated with the KDC) in the + absence of additional information, or as a default value for sites to + use for their principals' long-term keys in their Kerberos database. + It is simply the interpretation of the absence of the string-to-key + parameter field when the KDC has had an opportunity to provide it. + + Sample test vectors are given in Appendix B. + +5. Ciphertext Stealing + + Cipher block chaining is used to encrypt messages, with the initial + vector stored in the cipher state. Unlike previous Kerberos + cryptosystems, we use ciphertext stealing to handle the possibly + partial final block of the message. + + Ciphertext stealing is described on pages 195-196 of [AC], and + section 8 of [RC5]; it has the advantage that no message expansion is + done during encryption of messages of arbitrary sizes as is typically + done in CBC mode with padding. Some errata for [RC5] are listed in + Appendix A and are considered part of the ciphertext stealing + technique as used here. + + Ciphertext stealing, as defined in [RC5], assumes that more than one + block of plain text is available. If exactly one block is to be + encrypted, that block is simply encrypted with AES (also known as ECB + mode). Input smaller than one block is padded at the end to one + block; the values of the padding bits are unspecified. + (Implementations MAY use all-zero padding, but protocols MUST NOT + rely on the result being deterministic. Implementations MAY use + random padding, but protocols MUST NOT rely on the result not being + deterministic. Note that in most cases, the Kerberos encryption + profile will add a random confounder independent of this padding.) + + For consistency, ciphertext stealing is always used for the last two + blocks of the data to be encrypted, as in [RC5]. If the data length + is a multiple of the block size, this is equivalent to plain CBC mode + with the last two ciphertext blocks swapped. + + A test vector is given in Appendix B. + + + + + + +Raeburn Standards Track [Page 3] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + The initial vector carried out from one encryption for use in a + subsequent encryption is the next-to-last block of the encryption + output; this is the encrypted form of the last plaintext block. When + decrypting, the next-to-last block of the supplied ciphertext is + carried forward as the next initial vector. If only one ciphertext + block is available (decrypting one block, or encrypting one block or + less), then that one block is carried out instead. + +6. Kerberos Algorithm Profile Parameters + + This is a summary of the parameters to be used with the simplified + algorithm profile described in [KCRYPTO]: + + +--------------------------------------------------------------------+ + | protocol key format 128- or 256-bit string | + | | + | string-to-key function PBKDF2+DK with variable | + | iteration count (see | + | above) | + | | + | default string-to-key parameters 00 00 10 00 | + | | + | key-generation seed length key size | + | | + | random-to-key function identity function | + | | + | hash function, H SHA-1 | + | | + | HMAC output size, h 12 octets (96 bits) | + | | + | message block size, m 1 octet | + | | + | encryption/decryption functions, AES in CBC-CTS mode | + | E and D (cipher block size 16 | + | octets), with next-to- | + | last block (last block | + | if only one) as CBC-style | + | ivec | + +--------------------------------------------------------------------+ + + Using this profile with each key size gives us two each of encryption + and checksum algorithm definitions. + + + + + + + + + +Raeburn Standards Track [Page 4] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + +7. Assigned Numbers + + The following encryption type numbers are assigned: + + +--------------------------------------------------------------------+ + | encryption types | + +--------------------------------------------------------------------+ + | type name etype value key size | + +--------------------------------------------------------------------+ + | aes128-cts-hmac-sha1-96 17 128 | + | aes256-cts-hmac-sha1-96 18 256 | + +--------------------------------------------------------------------+ + + The following checksum type numbers are assigned: + + +--------------------------------------------------------------------+ + | checksum types | + +--------------------------------------------------------------------+ + | type name sumtype value length | + +--------------------------------------------------------------------+ + | hmac-sha1-96-aes128 15 96 | + | hmac-sha1-96-aes256 16 96 | + +--------------------------------------------------------------------+ + + These checksum types will be used with the corresponding encryption + types defined above. + +8. Security Considerations + + This new algorithm has not been around long enough to receive the + decades of intense analysis that DES has received. It is possible + that some weakness exists that has not been found by the + cryptographers analyzing these algorithms before and during the AES + selection process. + + The use of the HMAC function has drawbacks for certain pass phrase + lengths. For example, a pass phrase longer than the hash function + block size (64 bytes, for SHA-1) is hashed to a smaller size (20 + bytes) before applying the main HMAC algorithm. However, entropy is + generally sparse in pass phrases, especially in long ones, so this + may not be a problem in the rare cases of users with long pass + phrases. + + Also, generating a 256-bit key from a pass phrase of any length may + be deceptive, as the effective entropy in pass-phrase-derived key + cannot be nearly that large given the properties of the string-to-key + function described here. + + + + +Raeburn Standards Track [Page 5] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + The iteration count in PBKDF2 appears to be useful primarily as a + constant multiplier for the amount of work required for an attacker + using brute-force methods. Unfortunately, it also multiplies, by the + same amount, the work needed by a legitimate user with a valid + password. Thus the work factor imposed on an attacker (who may have + many powerful workstations at his disposal) must be balanced against + the work factor imposed on the legitimate user (who may have a PDA or + cell phone); the available computing power on either side increases + as time goes on, as well. A better way to deal with the brute-force + attack is through preauthentication mechanisms that provide better + protection of the user's long-term key. Use of such mechanisms is + out of the scope of this document. + + If a site does wish to use this means of protection against a brute- + force attack, the iteration count should be chosen based on the + facilities available to both attacker and legitimate user, and the + amount of work the attacker should be required to perform to acquire + the key or password. + + As an example: + + The author's tests on a 2GHz Pentium 4 system indicated that in + one second, nearly 90,000 iterations could be done, producing a + 256-bit key. This was using the SHA-1 assembly implementation + from OpenSSL, and a pre-release version of the PBKDF2 code for + MIT's Kerberos package, on a single system. No attempt was made + to do multiple hashes in parallel, so we assume an attacker doing + so can probably do at least 100,000 iterations per second -- + rounded up to 2**17, for ease of calculation. For simplicity, we + also assume the final AES encryption step costs nothing. + + Paul Leach estimates [LEACH] that a password-cracking dictionary + may have on the order of 2**21 entries, with capitalization, + punctuation, and other variations contributing perhaps a factor of + 2**11, giving a ballpark estimate of 2**32. + + Thus, for a known iteration count N and a known salt string, an + attacker with some number of computers comparable to the author's + would need roughly N*2**15 CPU seconds to convert the entire + dictionary plus variations into keys. + + An attacker using a dozen such computers for a month would have + roughly 2**25 CPU seconds available. So using 2**12 (4,096) + iterations would mean an attacker with a dozen such computers + dedicated to a brute-force attack against a single key (actually, + any password-derived keys sharing the same salt and iteration + + + + + +Raeburn Standards Track [Page 6] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + count) would process all the variations of the dictionary entries + in four months and, on average, would likely find the user's + password in two months. + + Thus, if this form of attack is of concern, users should be + required to change their passwords every few months, and an + iteration count a few orders of magnitude higher should be chosen. + Perhaps several orders of magnitude, as many users will tend to + use the shorter and simpler passwords (to the extent they can, + given a site's password quality checks) that the attacker would + likely try first. + + Since this estimate is based on currently available CPU power, the + iteration counts used for this mode of defense should be increased + over time, at perhaps 40%-60% each year or so. + + Note that if the attacker has a large amount of storage available, + intermediate results could be cached, saving a lot of work for the + next attack with the same salt and a greater number of iterations + than had been run at the point where the intermediate results were + saved. Thus, it would be wise to generate a new random salt + string when passwords are changed. The default salt string, + derived from the principal name, only protects against the use of + one dictionary of keys against multiple users. + + If the PBKDF2 iteration count can be spoofed by an intruder on the + network, and the limit on the accepted iteration count is very high, + the intruder may be able to introduce a form of denial of service + attack against the client by sending a very high iteration count, + causing the client to spend a great deal of CPU time computing an + incorrect key. + + An intruder spoofing the KDC reply, providing a low iteration count + and reading the client's reply from the network, may be able to + reduce the work needed in the brute-force attack outlined above. + Thus, implementations may seek to enforce lower bounds on the number + of iterations that will be used. + + Since threat models and typical end-user equipment will vary widely + from site to site, allowing site-specific configuration of such + bounds is recommended. + + Any benefit against other attacks specific to the HMAC or SHA-1 + algorithms is probably achieved with a fairly small number of + iterations. + + + + + + +Raeburn Standards Track [Page 7] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + In the "optimistic preauthentication" case mentioned in section 3, + the client may attempt to produce a key without first communicating + with the KDC. If the client has no additional information, it can + only guess as to the iteration count to be used. Even such + heuristics as "iteration count X was used to acquire tickets for the + same principal only N hours ago" can be wrong. Given the + recommendation above for increasing the iteration counts used over + time, it is impossible to recommend any specific default value for + this case; allowing site-local configuration is recommended. (If the + lower and upper bound checks described above are implemented, the + default count for optimistic preauthentication should be between + those bounds.) + + Ciphertext stealing mode, as it requires no additional padding in + most cases, will reveal the exact length of each message being + encrypted rather than merely bounding it to a small range of possible + lengths as in CBC mode. Such obfuscation should not be relied upon + at higher levels in any case; if the length must be obscured from an + outside observer, this should be done by intentionally varying the + length of the message to be encrypted. + +9. IANA Considerations + + Kerberos encryption and checksum type values used in section 7 were + previously reserved in [KCRYPTO] for the mechanisms defined in this + document. The registries have been updated to list this document as + the reference. + +10. Acknowledgements + + Thanks to John Brezak, Gerardo Diaz Cuellar, Ken Hornstein, Paul + Leach, Marcus Watts, Larry Zhu, and others for feedback on earlier + versions of this document. + + + + + + + + + + + + + + + + + + +Raeburn Standards Track [Page 8] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + +A. Errata for RFC 2040 Section 8 + + (Copied from the RFC Editor's errata web site on July 8, 2004.) + + Reported By: Bob Baldwin; baldwin@plusfive.com + Date: Fri, 26 Mar 2004 06:49:02 -0800 + + In Section 8, Description of RC5-CTS, of the encryption method, + it says: + + 1. Exclusive-or Pn-1 with the previous ciphertext + block, Cn-2, to create Xn-1. + + It should say: + + 1. Exclusive-or Pn-1 with the previous ciphertext + block, Cn-2, to create Xn-1. For short messages where + Cn-2 does not exist, use IV. + + Reported By: Bob Baldwin; baldwin@plusfive.com + Date: Mon, 22 Mar 2004 20:26:40 -0800 + + In Section 8, first paragraph, second sentence says: + + This mode handles any length of plaintext and produces ciphertext + whose length matches the plaintext length. + + In Section 8, first paragraph, second sentence should read: + + This mode handles any length of plaintext longer than one + block and produces ciphertext whose length matches the + plaintext length. + + In Section 8, step 6 of the decryption method says: + + 6. Decrypt En to create Pn-1. + + In Section 8, step 6 of the decryption method should read: + + 6. Decrypt En and exclusive-or with Cn-2 to create Pn-1. + For short messages where Cn-2 does not exist, use the IV. + + + + + + + + + + +Raeburn Standards Track [Page 9] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + +B. Sample Test Vectors + + Sample values for the PBKDF2 HMAC-SHA1 string-to-key function are + included below. + + Iteration count = 1 + Pass phrase = "password" + Salt = "ATHENA.MIT.EDUraeburn" + 128-bit PBKDF2 output: + cd ed b5 28 1b b2 f8 01 56 5a 11 22 b2 56 35 15 + 128-bit AES key: + 42 26 3c 6e 89 f4 fc 28 b8 df 68 ee 09 79 9f 15 + 256-bit PBKDF2 output: + cd ed b5 28 1b b2 f8 01 56 5a 11 22 b2 56 35 15 + 0a d1 f7 a0 4b b9 f3 a3 33 ec c0 e2 e1 f7 08 37 + 256-bit AES key: + fe 69 7b 52 bc 0d 3c e1 44 32 ba 03 6a 92 e6 5b + bb 52 28 09 90 a2 fa 27 88 39 98 d7 2a f3 01 61 + + Iteration count = 2 + Pass phrase = "password" + Salt="ATHENA.MIT.EDUraeburn" + 128-bit PBKDF2 output: + 01 db ee 7f 4a 9e 24 3e 98 8b 62 c7 3c da 93 5d + 128-bit AES key: + c6 51 bf 29 e2 30 0a c2 7f a4 69 d6 93 bd da 13 + 256-bit PBKDF2 output: + 01 db ee 7f 4a 9e 24 3e 98 8b 62 c7 3c da 93 5d + a0 53 78 b9 32 44 ec 8f 48 a9 9e 61 ad 79 9d 86 + 256-bit AES key: + a2 e1 6d 16 b3 60 69 c1 35 d5 e9 d2 e2 5f 89 61 + 02 68 56 18 b9 59 14 b4 67 c6 76 22 22 58 24 ff + + Iteration count = 1200 + Pass phrase = "password" + Salt = "ATHENA.MIT.EDUraeburn" + 128-bit PBKDF2 output: + 5c 08 eb 61 fd f7 1e 4e 4e c3 cf 6b a1 f5 51 2b + 128-bit AES key: + 4c 01 cd 46 d6 32 d0 1e 6d be 23 0a 01 ed 64 2a + 256-bit PBKDF2 output: + 5c 08 eb 61 fd f7 1e 4e 4e c3 cf 6b a1 f5 51 2b + a7 e5 2d db c5 e5 14 2f 70 8a 31 e2 e6 2b 1e 13 + 256-bit AES key: + 55 a6 ac 74 0a d1 7b 48 46 94 10 51 e1 e8 b0 a7 + 54 8d 93 b0 ab 30 a8 bc 3f f1 62 80 38 2b 8c 2a + + + + + +Raeburn Standards Track [Page 10] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + Iteration count = 5 + Pass phrase = "password" + Salt=0x1234567878563412 + 128-bit PBKDF2 output: + d1 da a7 86 15 f2 87 e6 a1 c8 b1 20 d7 06 2a 49 + 128-bit AES key: + e9 b2 3d 52 27 37 47 dd 5c 35 cb 55 be 61 9d 8e + 256-bit PBKDF2 output: + d1 da a7 86 15 f2 87 e6 a1 c8 b1 20 d7 06 2a 49 + 3f 98 d2 03 e6 be 49 a6 ad f4 fa 57 4b 6e 64 ee + 256-bit AES key: + 97 a4 e7 86 be 20 d8 1a 38 2d 5e bc 96 d5 90 9c + ab cd ad c8 7c a4 8f 57 45 04 15 9f 16 c3 6e 31 + (This test is based on values given in [PECMS].) + + Iteration count = 1200 + Pass phrase = (64 characters) + "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX" + Salt="pass phrase equals block size" + 128-bit PBKDF2 output: + 13 9c 30 c0 96 6b c3 2b a5 5f db f2 12 53 0a c9 + 128-bit AES key: + 59 d1 bb 78 9a 82 8b 1a a5 4e f9 c2 88 3f 69 ed + 256-bit PBKDF2 output: + 13 9c 30 c0 96 6b c3 2b a5 5f db f2 12 53 0a c9 + c5 ec 59 f1 a4 52 f5 cc 9a d9 40 fe a0 59 8e d1 + 256-bit AES key: + 89 ad ee 36 08 db 8b c7 1f 1b fb fe 45 94 86 b0 + 56 18 b7 0c ba e2 20 92 53 4e 56 c5 53 ba 4b 34 + + Iteration count = 1200 + Pass phrase = (65 characters) + "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX" + Salt = "pass phrase exceeds block size" + 128-bit PBKDF2 output: + 9c ca d6 d4 68 77 0c d5 1b 10 e6 a6 87 21 be 61 + 128-bit AES key: + cb 80 05 dc 5f 90 17 9a 7f 02 10 4c 00 18 75 1d + 256-bit PBKDF2 output: + 9c ca d6 d4 68 77 0c d5 1b 10 e6 a6 87 21 be 61 + 1a 8b 4d 28 26 01 db 3b 36 be 92 46 91 5e c8 2a + 256-bit AES key: + d7 8c 5c 9c b8 72 a8 c9 da d4 69 7f 0b b5 b2 d2 + 14 96 c8 2b eb 2c ae da 21 12 fc ee a0 57 40 1b + + + + + + + +Raeburn Standards Track [Page 11] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + Iteration count = 50 + Pass phrase = g-clef (0xf09d849e) + Salt = "EXAMPLE.COMpianist" + 128-bit PBKDF2 output: + 6b 9c f2 6d 45 45 5a 43 a5 b8 bb 27 6a 40 3b 39 + 128-bit AES key: + f1 49 c1 f2 e1 54 a7 34 52 d4 3e 7f e6 2a 56 e5 + 256-bit PBKDF2 output: + 6b 9c f2 6d 45 45 5a 43 a5 b8 bb 27 6a 40 3b 39 + e7 fe 37 a0 c4 1e 02 c2 81 ff 30 69 e1 e9 4f 52 + 256-bit AES key: + 4b 6d 98 39 f8 44 06 df 1f 09 cc 16 6d b4 b8 3c + 57 18 48 b7 84 a3 d6 bd c3 46 58 9a 3e 39 3f 9e + + Some test vectors for CBC with ciphertext stealing, using an initial + vector of all-zero. + + AES 128-bit key: + 0000: 63 68 69 63 6b 65 6e 20 74 65 72 69 79 61 6b 69 + + IV: + 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + Input: + 0000: 49 20 77 6f 75 6c 64 20 6c 69 6b 65 20 74 68 65 + 0010: 20 + Output: + 0000: c6 35 35 68 f2 bf 8c b4 d8 a5 80 36 2d a7 ff 7f + 0010: 97 + Next IV: + 0000: c6 35 35 68 f2 bf 8c b4 d8 a5 80 36 2d a7 ff 7f + + IV: + 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + Input: + 0000: 49 20 77 6f 75 6c 64 20 6c 69 6b 65 20 74 68 65 + 0010: 20 47 65 6e 65 72 61 6c 20 47 61 75 27 73 20 + Output: + 0000: fc 00 78 3e 0e fd b2 c1 d4 45 d4 c8 ef f7 ed 22 + 0010: 97 68 72 68 d6 ec cc c0 c0 7b 25 e2 5e cf e5 + Next IV: + 0000: fc 00 78 3e 0e fd b2 c1 d4 45 d4 c8 ef f7 ed 22 + + + + + + + + + + +Raeburn Standards Track [Page 12] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + IV: + 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + Input: + 0000: 49 20 77 6f 75 6c 64 20 6c 69 6b 65 20 74 68 65 + 0010: 20 47 65 6e 65 72 61 6c 20 47 61 75 27 73 20 43 + Output: + 0000: 39 31 25 23 a7 86 62 d5 be 7f cb cc 98 eb f5 a8 + 0010: 97 68 72 68 d6 ec cc c0 c0 7b 25 e2 5e cf e5 84 + Next IV: + 0000: 39 31 25 23 a7 86 62 d5 be 7f cb cc 98 eb f5 a8 + + IV: + 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + Input: + 0000: 49 20 77 6f 75 6c 64 20 6c 69 6b 65 20 74 68 65 + 0010: 20 47 65 6e 65 72 61 6c 20 47 61 75 27 73 20 43 + 0020: 68 69 63 6b 65 6e 2c 20 70 6c 65 61 73 65 2c + Output: + 0000: 97 68 72 68 d6 ec cc c0 c0 7b 25 e2 5e cf e5 84 + 0010: b3 ff fd 94 0c 16 a1 8c 1b 55 49 d2 f8 38 02 9e + 0020: 39 31 25 23 a7 86 62 d5 be 7f cb cc 98 eb f5 + Next IV: + 0000: b3 ff fd 94 0c 16 a1 8c 1b 55 49 d2 f8 38 02 9e + + IV: + 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + Input: + 0000: 49 20 77 6f 75 6c 64 20 6c 69 6b 65 20 74 68 65 + 0010: 20 47 65 6e 65 72 61 6c 20 47 61 75 27 73 20 43 + 0020: 68 69 63 6b 65 6e 2c 20 70 6c 65 61 73 65 2c 20 + Output: + 0000: 97 68 72 68 d6 ec cc c0 c0 7b 25 e2 5e cf e5 84 + 0010: 9d ad 8b bb 96 c4 cd c0 3b c1 03 e1 a1 94 bb d8 + 0020: 39 31 25 23 a7 86 62 d5 be 7f cb cc 98 eb f5 a8 + Next IV: + 0000: 9d ad 8b bb 96 c4 cd c0 3b c1 03 e1 a1 94 bb d8 + + + + + + + + + + + + + + + +Raeburn Standards Track [Page 13] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + + IV: + 0000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 + Input: + 0000: 49 20 77 6f 75 6c 64 20 6c 69 6b 65 20 74 68 65 + 0010: 20 47 65 6e 65 72 61 6c 20 47 61 75 27 73 20 43 + 0020: 68 69 63 6b 65 6e 2c 20 70 6c 65 61 73 65 2c 20 + 0030: 61 6e 64 20 77 6f 6e 74 6f 6e 20 73 6f 75 70 2e + Output: + 0000: 97 68 72 68 d6 ec cc c0 c0 7b 25 e2 5e cf e5 84 + 0010: 39 31 25 23 a7 86 62 d5 be 7f cb cc 98 eb f5 a8 + 0020: 48 07 ef e8 36 ee 89 a5 26 73 0d bc 2f 7b c8 40 + 0030: 9d ad 8b bb 96 c4 cd c0 3b c1 03 e1 a1 94 bb d8 + Next IV: + 0000: 48 07 ef e8 36 ee 89 a5 26 73 0d bc 2f 7b c8 40 + +Normative References + + [AC] Schneier, B., "Applied Cryptography", second edition, John + Wiley and Sons, New York, 1996. + + [AES] National Institute of Standards and Technology, U.S. + Department of Commerce, "Advanced Encryption Standard", + Federal Information Processing Standards Publication 197, + Washington, DC, November 2001. + + [KCRYPTO] Raeburn, K., "Encryption and Checksum Specifications for + Kerberos 5", RFC 3961, February 2005. + + [KEYWORDS] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [PKCS5] Kaliski, B., "PKCS #5: Password-Based Cryptography + Specification Version 2.0", RFC 2898, September 2000. + + [RC5] Baldwin, R. and R. Rivest, "The RC5, RC5-CBC, RC5-CBC-Pad, + and RC5-CTS Algorithms", RFC 2040, October 1996. + + [SHA1] National Institute of Standards and Technology, U.S. + Department of Commerce, "Secure Hash Standard", Federal + Information Processing Standards Publication 180-1, + Washington, DC, April 1995. + + + + + + + + + + +Raeburn Standards Track [Page 14] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + +Informative References + + [LEACH] Leach, P., email to IETF Kerberos working group mailing + list, 5 May 2003, ftp://ftp.ietf.org/ietf-mail- + archive/krb-wg/2003-05.mail. + + [PECMS] Gutmann, P., "Password-based Encryption for CMS", RFC + 3211, December 2001. + +Author's Address + + Kenneth Raeburn + Massachusetts Institute of Technology + 77 Massachusetts Avenue + Cambridge, MA 02139 + + EMail: raeburn@mit.edu + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Raeburn Standards Track [Page 15] + +RFC 3962 AES Encryption for Kerberos 5 February 2005 + + +Full Copyright Statement + + Copyright (C) The Internet Society (2005). + + This document is subject to the rights, licenses and restrictions + contained in BCP 78, and except as set forth therein, the authors + retain all their rights. + + This document and the information contained herein are provided on an + "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS + OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET + ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, + INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE + INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED + WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + +Intellectual Property + + The IETF takes no position regarding the validity or scope of any + Intellectual Property Rights or other rights that might be claimed to + pertain to the implementation or use of the technology described in + this document or the extent to which any license under such rights + might or might not be available; nor does it represent that it has + made any independent effort to identify any such rights. 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