4 <Network Working Group> Larry Zhu
5 Internet Draft Karthik Jaganathan
6 Updates: 1964 Microsoft
7 Category: Standards Track Sam Hartman
8 draft-ietf-krb-wg-gssapi-cfx-02.txt MIT
10 Expires: March 29, 2004
12 The Kerberos Version 5 GSS-API Mechanism: Version 2
16 This document is an Internet-Draft and is in full conformance with
17 all provisions of Section 10 of [RFC-2026].
19 Internet-Drafts are working documents of the Internet Engineering
20 Task Force (IETF), its areas, and its working groups. Note that
21 other groups may also distribute working documents as Internet-
22 Drafts. Internet-Drafts are draft documents valid for a maximum of
23 six months and may be updated, replaced, or obsoleted by other
24 documents at any time. It is inappropriate to use Internet-Drafts
25 as reference material or to cite them other than as "work in
28 The list of current Internet-Drafts can be accessed at
29 http://www.ietf.org/ietf/1id-abstracts.txt.
31 The list of Internet-Draft Shadow Directories can be accessed at
32 http://www.ietf.org/shadow.html.
36 This memo defines protocols, procedures, and conventions to be
37 employed by peers implementing the Generic Security Service
38 Application Program Interface (GSS-API as specified in [RFC-2743])
39 when using the Kerberos Version 5 mechanism (as specified in
42 [RFC-1964] is updated and incremental changes are proposed in
43 response to recent developments such as the introduction of Kerberos
44 crypto framework [KCRYPTO]. These changes support the inclusion of
45 new cryptosystems based on crypto profiles [KCRYPTO], by defining
46 new per-message and context-deletion tokens along with their
47 encryption and checksum algorithms.
49 Conventions used in this document
51 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
52 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
53 document are to be interpreted as described in [RFC-2119].
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63 [KCRYPTO] defines a generic framework for describing encryption and
64 checksum types to be used with the Kerberos protocol and associated
67 [RFC-1964] describes the GSS-API mechanism for Kerberos Version 5.
68 It defines the format of context initiation, per-message and context
69 deletion tokens and uses algorithm identifiers for each cryptosystem
70 in per message and context deletion tokens.
72 The approach taken in this document obviates the need for algorithm
73 identifiers. This is accomplished by using the same encryption and
74 checksum algorithms specified by the crypto profile [KCRYPTO] for
75 the session key or subkey that is created during context
76 negotiation. Message layouts of the per-message and context
77 deletion tokens are therefore revised to remove algorithm indicators
78 and also to add extra information to support the generic crypto
81 Tokens transferred between GSS-API peers for security context
82 initiation are also described in this document. The data elements
83 exchanged between a GSS-API endpoint implementation and the Kerberos
84 KDC are not specific to GSS-API usage and are therefore defined
85 within [KRBCLAR] rather than within this specification.
87 The new token formats specified in this memo MUST be used with all
88 "newer" encryption types [KRBCLAR] and MAY be used with "older"
89 encryption types, provided that the initiator and acceptor know,
90 from the context establishment, that they can both process these new
93 "Newer" encryption types are those which have been specified along
94 with or since the new Kerberos cryptosystem specification [KCRYPTO],
95 as defined in section 3.1.3 of [KRBCLAR].
97 Note that in this document, the term "little endian order" is used
98 for brevity to refer to the least-significant-byte-first encoding,
99 while the term "big endian order" is for the most-significant-byte-
102 2. Key Derivation for Per-Message and Context Deletion Tokens
104 To limit the exposure of a given key, [KCRYPTO] adopted "one-way"
105 "entropy-preserving" derived keys, for different purposes or key
106 usages, from a base key or protocol key. This document defines four
107 key usage values below for signing and sealing messages:
110 -------------------------------------
111 KG-USAGE-ACCEPTOR-SEAL 22
112 KG-USAGE-ACCEPTOR-SIGN 23
113 KG-USAGE-INITIATOR-SEAL 24
114 KG-USAGE-INITIATOR-SIGN 25
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121 When the sender is the context acceptor, KG-USAGE-ACCEPTOR-SIGN is
122 used as the usage number in the key derivation function for deriving
123 keys to be used in MIC and context deletion tokens, and KG-USAGE-
124 ACCEPTOR-SEAL is used for Wrap tokens; similarly when the sender is
125 the context initiator, KG-USAGE-INITIATOR-SIGN is used as the usage
126 number in the key derivation function for MIC and context deletion
127 tokens, KG-USAGE-INITIATOR-SEAL is used for Wrap Tokens. Even if
128 the Wrap token does not provide for confidentiality the same usage
129 values specified above are used.
131 During context initiation, the acceptor MAY assert a subkey, and if
132 so, subsequent messages MUST use this subkey as the protocol key and
133 these messages MUST be flagged as "AcceptorSubkey" as described in
136 3. Quality of Protection
138 The GSS-API specification [RFC-2743] provides for Quality of
139 Protection (QOP) values that can be used by applications to request
140 a certain type of encryption or signing. A zero QOP value is used
141 to indicate the "default" protection; applications which use the
142 default QOP are not guaranteed to be portable across implementations
143 or even inter-operate with different deployment configurations of
144 the same implementation. Using an algorithm that is different from
145 the one for which the key is defined may not be appropriate.
146 Therefore, when the new method in this document is used, the QOP
149 The encryption and checksum algorithms in per-message and context
150 deletion tokens are now implicitly defined by the algorithms
151 associated with the session key or subkey. Algorithms identifiers
152 as described in [RFC-1964] are therefore no longer needed and
153 removed from the new token headers.
155 4. Definitions and Token Formats
157 This section provides terms and definitions, as well as descriptions
158 for tokens specific to the Kerberos Version 5 GSS-API mechanism.
160 4.1. Initial Context Tokens
162 Per [RFC-2743], all context initiation tokens emitted by the
163 Kerberos V5 GSS-API mechanism will have the framing shown below:
165 GSS-API DEFINITIONS ::=
169 MechType ::= OBJECT IDENTIFIER
170 -- representing Kerberos V5 mechanism
173 -- option indication (delegation, etc.) indicated within
174 -- mechanism-specific token
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180 [APPLICATION 0] IMPLICIT SEQUENCE {
182 innerToken ANY DEFINED BY thisMech
183 -- contents mechanism-specific
184 -- ASN.1 structure not required
189 The innerToken field starts with a two-byte token-identifier
190 (TOK_ID) expressed in big endian order, followed by a Kerberos
193 Here are the TOK_ID values used in the initial tokens:
195 Token TOK_ID Value in Hex
196 -----------------------------------------
201 Where Kerberos message KRB_AP_REQUEST, KRB_AP_REPLY, and KRB_ERROR
202 are defined in [KRBCLAR].
204 If an unknown token ID is received in the first context token, the
205 receiver MUST return GSS_S_CONTINUE_NEEDED major status, and the
206 returned output token MUST contain a KRB_ERROR message with the
207 error code KRB_AP_ERR_MSG_TYPE [KRBCLAR].
209 4.1.1. Authenticator Checksum
211 The authenticator in the KRB_AP_REQ message MUST include the
212 optional sequence number and the checksum field. The checksum field
213 is used to convey service flags, channel bindings, and optional
214 delegation information. It MUST have a type of 0x8003. The length
215 of the checksum MUST be 24 bytes when delegation is not used. When
216 delegation is used, a ticket-granting ticket will be transferred in
217 a KRB_CRED message. The ticket SHOULD have its forwardable flag
218 set. The KRB_CRED message MUST be encrypted in the session key of
219 the ticket used to authenticate the context.
221 The format of the authenticator checksum field is as follows.
223 Byte Name Description
224 -----------------------------------------------------------------
225 0..3 Lgth Number of bytes in Bnd field; Currently contains
226 hex value 10 00 00 00 (16, represented in little-
228 4..19 Bnd Channel binding information, as describe in
230 20..23 Flags Four-byte context-establishment flags in little-
231 endian order as described in section 4.1.1.1.
232 24..25 DlgOpt The Delegation Option identifier (=1) [optional]
233 26..27 Dlgth The length of the Deleg field [optional]
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240 28..n Deleg A KRB_CRED message (n = Dlgth + 29) [optional]
242 4.1.1.1. Checksum Flags Field
244 The checksum "Flags" field is used to convey service options or
245 extension negotiation information. The following context
246 establishment flags are defined in [RFC-2744].
249 ---------------------------------
253 GSS_C_SEQUENCE_FLAG 8
258 Context establishment flags are exposed to the calling application.
259 If the calling application desires a particular service option then
260 it requests that option via GSS_Init_sec_context() [RFC-2743]. An
261 implementation that supports a particular option or extension SHOULD
262 then set the appropriate flag in the checksum Flags field.
264 The receiver MUST ignore unknown checksum flags.
266 4.1.1.2. Channel Binding Information
268 Channel bindings are user-specified tags to identify a given context
269 to the peer application. These tags are intended to be used to
270 identify the particular communications channel that carries the
273 When using C language bindings, channel bindings are communicated to
274 the GSS-API using the following structure [RFC-2744]:
276 typedef struct gss_channel_bindings_struct {
277 OM_uint32 initiator_addrtype;
278 gss_buffer_desc initiator_address;
279 OM_uint32 acceptor_addrtype;
280 gss_buffer_desc acceptor_address;
281 gss_buffer_desc application_data;
282 } *gss_channel_bindings_t;
284 The member fields and constants used for different address types are
285 defined in [RFC-2744].
287 The "Bnd" field contains the MD5 hash of channel bindings, taken
288 over all non-null components of bindings, in order of declaration.
289 Integer fields within channel bindings are represented in little-
290 endian order for the purposes of the MD5 calculation.
292 In computing the contents of the Bnd field, the following detailed
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301 (1) Each integer field shall be formatted into four bytes, using
302 little endian byte ordering, for purposes of MD5 hash computation.
304 (2) All input length fields within gss_buffer_desc elements of a
305 gss_channel_bindings_struct even those which are zero-valued, shall
306 be included in the hash calculation; the value elements of
307 gss_buffer_desc elements shall be dereferenced, and the resulting
308 data shall be included within the hash computation, only for the
309 case of gss_buffer_desc elements having non-zero length specifiers.
311 (3) If the caller passes the value GSS_C_NO_BINDINGS instead of a
312 valid channel binding structure, the Bnd field shall be set to 16
315 4.2. Per-Message and Context Deletion Tokens
317 Three classes of tokens are defined in this section: "MIC" tokens,
318 emitted by calls to GSS_GetMIC() and consumed by calls to
319 GSS_VerifyMIC(), "Wrap" tokens, emitted by calls to GSS_Wrap() and
320 consumed by calls to GSS_Unwrap(), and context deletion tokens,
321 emitted by calls to GSS_Delete_sec_context() and consumed by calls
322 to GSS_Process_context_token().
324 The new per-message and context deletion tokens introduced here do
325 not include the pseudo ASN.1 header used by the initial context
326 tokens. These new tokens are designed to be used with newer crypto
327 systems that can, for example, have variable-size checksums.
329 4.2.1. Sequence Number and Direction Indicator
331 To distinguish intentionally-repeated messages from maliciously-
332 replayed ones, per-message and context deletion tokens contain a
333 sequence number field, which is a 64 bit integer expressed in big
334 endian order. One separate bit is used as the direction-indicator
335 in the Flags field as described in section 4.2.2, thus preventing an
336 adversary from sending back the same message in the reverse
337 direction and having it accepted. Both the sequence number and the
338 direction-indicator are protected by the encryption and checksum
339 procedures specified in section 4.2.4.
341 After sending a GSS_GetMIC() or GSS_Wrap() token, the sender's
342 sequence numbers are incremented by one.
346 The "Flags" field is a one-byte integer used to indicate a set of
347 attributes. The meanings of bits in this field (the least
348 significant bit is bit 0) are as follows:
351 ---------------------------------------------------------------
352 0 SentByAcceptor When set, this flag indicates the sender
353 is the context acceptor. When not set,
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360 it indicates the sender is the context
362 1 Sealed When set in Wrap tokens, this flag
363 indicates confidentiality is provided
364 for. It SHALL NOT be set in MIC and
365 context deletion tokens.
366 2 AcceptorSubkey A subkey asserted by the context acceptor
367 is used to protect the message.
369 The rest of available bits are reserved for future use and MUST be
370 cleared. The receiver MUST ignore unknown flags.
374 The "EC" (Extra Count) field is a two-byte integer field expressed
377 In Wrap tokens with confidentiality, the EC field is used to encode
378 the number of bytes in the filler, as described in section 4.2.4.
380 In Wrap tokens without confidentiality, the EC field is used to
381 encode the number of bytes in the trailing checksum, as described in
384 4.2.4. Encryption and Checksum Operations
386 The encryption algorithms defined by the crypto profiles provide for
387 integrity protection [KCRYPTO]. Therefore no separate checksum is
390 The result of decryption can be longer than the original plaintext
391 [KCRYPTO] and the extra trailing bytes are called "crypto-system
392 garbage". However, given the size of any plaintext data, one can
393 always find the next (possibly larger) size so that, when padding
394 the to-be-encrypted text to that size, there will be no crypto-
395 system garbage added [KCRYPTO].
397 In Wrap tokens that provide for confidentiality, the first 16 bytes
398 of the Wrap token (the "header") are appended to the plaintext data
399 before encryption. Filler bytes can be inserted between the
400 plaintext-data and the "header", and the values and size of the
401 filler octets are chosen by implementations, such that there is no
402 crypto-system garbage present after the decryption. The resulting
403 Wrap token is {"header" | encrypt(plaintext-data | filler |
404 "header")}, where encrypt() is the encryption operation (which
405 provides for integrity protection) defined in the crypto profile
406 [KCRYPTO], and the RRC field in the to-be-encrypted header contains
409 In Wrap tokens that do not provide for confidentiality, the checksum
410 is calculated first over the plaintext data, and then the first 16
411 bytes of the Wrap token (the "header"). Both the EC field and the
412 RRC field in the token header are filled with zeroes for the purpose
413 of calculating the checksum. The resulting Wrap token is {"header"
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420 | plaintext-data | get_mic(plaintext-data | "header")}, where
421 get_mic() is the checksum operation defined in the crypto profile
424 The parameters for the key and the cipher-state in the encrypt() and
425 get_mic() operations have been omitted for brevity.
427 For MIC tokens, the checksum is first calculated over the first 16
428 bytes of the MIC token and then the to-be-signed plaintext data.
430 The resulting Wrap and MIC tokens bind the data to the token header,
431 including the sequence number and the directional indicator.
433 For context deletion tokens, the checksum is calculated over the
434 first 16 bytes of the token message.
438 The "RRC" (Right Rotation Count) field in Wrap tokens is added to
439 allow the data to be encrypted in-place by existing [SSPI]
440 applications that do not provide an additional buffer for the
441 trailer (the cipher text after the in-place-encrypted data) in
442 addition to the buffer for the header (the cipher text before the
443 in-place-encrypted data). The resulting Wrap token in the previous
444 section, excluding the first 16 bytes of the token header, is
445 rotated to the right by "RRC" bytes. The net result is that "RRC"
446 bytes of trailing octets are moved toward the header. Consider the
447 following as an example of this rotation operation: Assume that the
448 RRC value is 3 and the token before the rotation is {"header" | aa |
449 bb | cc | dd | ee | ff | gg | hh}, the token after rotation would be
450 {"header" | ff | gg | hh | aa | bb | cc | dd | ee }, where {aa | bb
451 | cc |...| hh} is used to indicate the byte sequence.
453 The RRC field is expressed as a two-byte integer in big endian
456 The rotation count value is chosen by the sender based on
457 implementation details, and the receiver MUST be able to interpret
458 all possible rotation count values.
460 4.2.6. Message Layouts
462 Per-message and context deletion token messages start with a two-
463 byte token identifier (TOK_ID) field, expressed in big endian order.
464 These tokens are defined separately in subsequent sub-sections.
468 Use of the GSS_GetMIC() call yields a token, separate from the user
469 data being protected, which can be used to verify the integrity of
470 that data as received. The token has the following format:
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477 Byte no Name Description
478 -----------------------------------------------------------------
479 0..1 TOK_ID Identification field. Tokens emitted by
480 GSS_GetMIC() contain the hex value 04 04
481 expressed in big endian order in this field.
482 2 Flags Attributes field, as described in section
484 3..7 Filler Contains five bytes of hex value FF.
485 8..15 SND_SEQ Sequence number field in clear text,
486 expressed in big endian order.
487 16..last SGN_CKSUM Checksum of byte 0..15 and the "to-be-
488 signed" data, where the checksum algorithm
489 is defined by the crypto profile for the
490 session key or subkey.
492 The Filler field is included in the checksum calculation for
493 simplicity. This is common to both MIC and context deletion token
494 checksum calculations.
498 Use of the GSS_Wrap() call yields a token, which consists of a
499 descriptive header, followed by a body portion that contains either
500 the input user data in plaintext concatenated with the checksum, or
501 the input user data encrypted. The GSS_Wrap() token has the
504 Byte no Name Description
505 ---------------------------------------------------------------
506 0..1 TOK_ID Identification field. Tokens emitted by
507 GSS_Wrap() contain the the hex value 05 04
508 expressed in big endian order in this field.
509 2 Flags Attributes field, as described in section
511 3 Filler Contains the hex value FF.
512 4..5 EC Contains the "extra count" field, in big
513 endian order as described in section 4.2.3.
514 6..7 RRC Contains the "right rotation count" in big
515 endian order, as described in section 4.2.5.
516 8..15 SND_SEQ Sequence number field in clear text,
517 expressed in big endian order.
518 16..last Data Encrypted data for Wrap tokens with
519 confidentiality, or plaintext data followed
520 by the checksum for Wrap tokens without
521 confidentiality, as described in section
522 4.2.4, where the encryption or checksum
523 algorithm is defined by the crypto profile
524 for the session key or subkey.
526 4.2.6.3. Context Deletion Tokens
528 The token emitted by GSS_Delete_sec_context() is based on the packet
529 format for tokens emitted by GSS_GetMIC(). The context-deletion
530 token has the following format:
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537 Byte no Name Description
538 -----------------------------------------------------------------
539 0..1 TOK_ID Identification field. Tokens emitted by
540 GSS_Delete_sec_context() contain the hex
541 value 04 05 expressed in big endian order in
543 2 Flags Attributes field, as described in section
545 3..7 Filler Contains five bytes of hex value FF.
546 8..15 SND_SEQ Sequence number field in clear text,
547 expressed in big endian order.
548 16..N SGN_CKSUM Checksum of byte 0..15, where the checksum
549 algorithm is defined by the crypto profile
550 for the session key or subkey.
552 5. Parameter Definitions
554 This section defines parameter values used by the Kerberos V5 GSS-
555 API mechanism. It defines interface elements in support of
556 portability, and assumes use of C language bindings per [RFC-2744].
558 5.1. Minor Status Codes
560 This section recommends common symbolic names for minor_status
561 values to be returned by the Kerberos V5 GSS-API mechanism. Use of
562 these definitions will enable independent implementers to enhance
563 application portability across different implementations of the
564 mechanism defined in this specification. (In all cases,
565 implementations of GSS_Display_status() will enable callers to
566 convert minor_status indicators to text representations.) Each
567 implementation should make available, through include files or other
568 means, a facility to translate these symbolic names into the
569 concrete values which a particular GSS-API implementation uses to
570 represent the minor_status values specified in this section.
572 It is recognized that this list may grow over time, and that the
573 need for additional minor_status codes specific to particular
574 implementations may arise. It is recommended, however, that
575 implementations should return a minor_status value as defined on a
576 mechanism-wide basis within this section when that code is
577 accurately representative of reportable status rather than using a
578 separate, implementation-defined code.
580 5.1.1. Non-Kerberos-specific codes
582 GSS_KRB5_S_G_BAD_SERVICE_NAME
583 /* "No @ in SERVICE-NAME name string" */
584 GSS_KRB5_S_G_BAD_STRING_UID
585 /* "STRING-UID-NAME contains nondigits" */
587 /* "UID does not resolve to username" */
588 GSS_KRB5_S_G_VALIDATE_FAILED
589 /* "Validation error" */
590 GSS_KRB5_S_G_BUFFER_ALLOC
591 /* "Couldn't allocate gss_buffer_t data" */
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598 GSS_KRB5_S_G_BAD_MSG_CTX
599 /* "Message context invalid" */
600 GSS_KRB5_S_G_WRONG_SIZE
601 /* "Buffer is the wrong size" */
602 GSS_KRB5_S_G_BAD_USAGE
603 /* "Credential usage type is unknown" */
604 GSS_KRB5_S_G_UNKNOWN_QOP
605 /* "Unknown quality of protection specified" */
607 5.1.2. Kerberos-specific-codes
609 GSS_KRB5_S_KG_CCACHE_NOMATCH
610 /* "Client principal in credentials does not match
612 GSS_KRB5_S_KG_KEYTAB_NOMATCH
613 /* "No key available for specified service principal" */
614 GSS_KRB5_S_KG_TGT_MISSING
615 /* "No Kerberos ticket-granting ticket available" */
616 GSS_KRB5_S_KG_NO_SUBKEY
617 /* "Authenticator has no subkey" */
618 GSS_KRB5_S_KG_CONTEXT_ESTABLISHED
619 /* "Context is already fully established" */
620 GSS_KRB5_S_KG_BAD_SIGN_TYPE
621 /* "Unknown signature type in token" */
622 GSS_KRB5_S_KG_BAD_LENGTH
623 /* "Invalid field length in token" */
624 GSS_KRB5_S_KG_CTX_INCOMPLETE
625 /* "Attempt to use incomplete security context" */
629 All implementations of this specification shall be capable of
630 accepting buffers of at least 16K bytes as input to GSS_GetMIC(),
631 GSS_VerifyMIC(), and GSS_Wrap(), and shall be capable of accepting
632 the output_token generated by GSS_Wrap() for a 16K byte input buffer
633 as input to GSS_Unwrap(). Support for larger buffer sizes is
634 optional but recommended.
636 6. Backwards Compatibility Considerations
638 The new token formats defined in this document will only be
639 recognized by new implementations. To address this, implementations
640 can always use the explicit sign or seal algorithm in [RFC-1964]
641 when the key type corresponds to "older" enctypes. An alternative
642 approach might be to retry sending the message with the sign or seal
643 algorithm explicitly defined as in [RFC-1964]. However this would
644 require either the use of a mechanism such as [RFC-2478] to securely
645 negotiate the method or the use out of band mechanism to choose
646 appropriate mechanism. For this reason, it is RECOMMENDED that the
647 new token formats defined in this document SHOULD be used only if
648 both peers are known to support the new mechanism during context
649 negotiation, for example, either because of the use of "new"
650 enctypes or because of the use of Kerberos Version 5 extensions.
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657 7. Security Considerations
659 Under the current mechanism, no negotiation of algorithm types
660 occurs, so server-side (acceptor) implementations cannot request
661 that clients not use algorithm types not understood by the server.
662 However, administration of the server's Kerberos data (e.g., the
663 service key) has to be done in communication with the KDC, and it is
664 from the KDC that the client will request credentials. The KDC
665 could therefore be given the task of limiting session keys for a
666 given service to types actually supported by the Kerberos and GSSAPI
667 software on the server.
669 This does have a drawback for cases where a service principal name
670 is used both for GSSAPI-based and non-GSSAPI-based communication
671 (most notably the "host" service key), if the GSSAPI implementation
672 does not understand (for example) AES [AES-KRB5] but the Kerberos
673 implementation does. It means that AES session keys cannot be
674 issued for that service principal, which keeps the protection of
675 non-GSSAPI services weaker than necessary. KDC administrators
676 desiring to limit the session key types to support interoperability
677 with such GSSAPI implementations should carefully weigh the
678 reduction in protection offered by such mechanisms against the
679 benefits of interoperability.
683 The authors wish to acknowledge the contributions from the following
686 Ken Raeburn and Nicolas Williams corrected many of our errors in the
687 use of generic profiles and were instrumental in the creation of this
690 The text for security considerations was contributed by Ken Raeburn.
692 Sam Hartman and Ken Raeburn suggested the "floating trailer" idea,
693 namely the encoding of the RRC field.
695 Sam Hartman and Nicolas Williams recommended the replacing our
696 earlier key derivation function for directional keys with different
697 key usage numbers for each direction as well as retaining the
698 directional bit for maximum compatibility.
700 Paul Leach provided numerous suggestions and comments.
702 Scott Field, Richard Ward, Dan Simon, and Kevin Damour also provided
703 valuable inputs on this draft.
705 Jeffrey Hutzelman provided comments on channel bindings and suggested
706 many editorial changes.
708 This document retains some of the text of RFC-1964 in relevant
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718 9.1. Normative References
720 [RFC-2026] Bradner, S., "The Internet Standards Process -- Revision
721 3", BCP 9, RFC 2026, October 1996.
723 [RFC-2119] Bradner, S., "Key words for use in RFCs to Indicate
724 Requirement Levels", BCP 14, RFC 2119, March 1997.
726 [RFC-2743] Linn, J., "Generic Security Service Application Program
727 Interface Version 2, Update 1", RFC 2743, January 2000.
729 [RFC-2744] Wray, J., "Generic Security Service API Version 2: C-
730 bindings", RFC 2744, January 2000.
732 [RFC-1964] Linn, J., "The Kerberos Version 5 GSS-API Mechanism",
735 [KCRYPTO] Raeburn, K., "Encryption and Checksum Specifications for
736 Kerberos 5", draft-ietf-krb-wg-crypto-05.txt, June, 2003. Work in
739 [KRBCLAR] Neuman, C., Kohl, J., Ts'o T., Yu T., Hartman, S.,
740 Raeburn, K., "The Kerveros Network Authentication Service (V5)",
741 draft-ietf-krb-wg-kerberos-clarifications-04.txt, February 2002.
744 [AES-KRB5] Raeburn, K., "AES Encryption for Kerberos 5", draft-
745 raeburn-krb-rijndael-krb-05.txt, June 2003. Work in progress.
747 [RFC-2478] Baize, E., Pinkas D., "The Simple and Protected GSS-API
748 Negotiation Mechanism", RFC 2478, December 1998.
750 9.2. Informative References
752 [SSPI] Leach, P., "Security Service Provider Interface", Microsoft
753 Developer Network (MSDN), April 2003.
759 Redmond, WA 98052 - USA
760 EMail: LZhu@microsoft.com
764 Redmond, WA 98052 - USA
765 EMail: karthikj@microsoft.com
767 Zhu Internet Draft 13
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772 Massachusetts Institute of Technology
773 77 Massachusetts Avenue
774 Cambridge, MA 02139 - USA
775 Email: hartmans@MIT.EDU
825 Zhu Internet Draft 14
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830 Full Copyright Statement
832 Copyright (C) The Internet Society (date). All Rights Reserved.
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883 Zhu Internet Draft 15
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