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-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].
-
-
-
-
-
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-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.
-
-
-
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-
- 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.
-
-
-
-
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-
- 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.
-
-
-
-
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-
-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.
-
-
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-
- 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
-
-
-
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- 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.
-
-
-
-
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-
- 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.
-
-
-
-
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-
-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.
-
-
-
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-
-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
-
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-
- 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
-
-
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-
- 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
-
-
-
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-
- 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
-
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-Raeburn Standards Track [Page 13]
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-RFC 3962 AES Encryption for Kerberos 5 February 2005
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- 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.
-
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-RFC 3962 AES Encryption for Kerberos 5 February 2005
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-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
-
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-Raeburn Standards Track [Page 15]
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-RFC 3962 AES Encryption for Kerberos 5 February 2005
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-
-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.
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-Acknowledgement
-
- Funding for the RFC Editor function is currently provided by the
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-
-
-
-
-
-
-
-Raeburn Standards Track [Page 16]
-\f
git.samba.org / samba.git / blobdiff