Network Working Group C. Adams
Request for Comments: 2479 Entrust Technologies
Category: Informational December 1998
Independent Data Unit Protection Generic Security Service
Application Program Interface (IDUP-GSS-API)
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1998). All Rights Reserved.
ABSTRACT
The IDUP-GSS-API extends the GSS-API RFC-2078">[RFC-2078] for applications
requiring protection of a generic data unit (such as a file or
message) in a way which is independent of the protection of any other
data unit and independent of any concurrent contact with designated
"receivers" of the data unit. Thus, it is suitable for applications
such as secure electronic mail where data needs to be protected
without any on-line connection with the intended recipient(s) of that
data. The protection offered by IDUP includes services such as data
origin authentication with data integrity, data confidentiality with
data integrity, and support for non-repudiation services. Subsequent
to being protected, the data unit can be transferred to the
recipient(s) - or to an archive - perhaps to be processed
("unprotected") only days or years later.
Throughout the remainder of this document, the "unit" of data
described in the above paragraph will be referred to as an IDU
(Independent Data Unit). The IDU can be of any size (the application
may, if it wishes, split the IDU into pieces and have the protection
computed a piece at a time, but the resulting protection token
applies to the entire IDU). However, the primary characteristic of
an IDU is that it represents a stand-alone unit of data whose
protection is entirely independent of any other unit of data. If an
application protects several IDUs and sends them all to a single
receiver, the IDUs may be unprotected by that receiver in any order
over any time span; no logical connection of any kind is implied by
the protection process itself.
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As with RFC-2078, this IDUP-GSS-API definition provides security
services to callers in a generic fashion, supportable with a range of
underlying mechanisms and technologies and hence allowing source-
level portability of applications to different environments. This
specification defines IDUP-GSS-API services and primitives at a level
independent of underlying mechanism and programming language
environment, and is to be complemented by other, related
specifications:
- documents defining specific parameter bindings for particular
language environments;
- documents defining token formats, protocols, and procedures to
be implemented in order to realize IDUP-GSS-API services atop
particular security mechanisms.
TABLE OF CONTENTS
1. IDUP-GSS-API Characteristics and Concepts .................. 3
1.1. IDUP-GSS-API Constructs .................................. 5
1.1.1. Credentials ............................................ 5
1.1.2. Tokens ................................................. 5
1.1.3. Security Environment ................................... 6
1.1.4. Mechanism Types ........................................ 6
1.1.5. Naming ................................................. 6
1.1.6. Channel Bindings ....................................... 6
1.2. IDUP-GSS-API Features and Issues ......................... 6
1.2.1. Status Reporting ....................................... 6
1.2.2. Per-IDU Security Service Availability .................. 9
1.2.3. Per-IDU Replay Detection and Sequencing ................ 9
1.2.4. Quality of Protection .................................. 9
1.2.5. The Provision of Time .................................. 12
2. Interface Descriptions ..................................... 13
2.1. Credential management calls .............................. 14
2.1.1. Relationship to GSS-API ................................ 14
2.2. Environment-level calls .................................. 15
2.2.1. Relationship to GSS-API ................................ 15
2.2.2. IDUP_Establish_Env call ................................ 15
2.2.3. IDUP_Abolish_Env call .................................. 19
2.2.4. IDUP_Inquire_Env call .................................. 19
2.3. Per-IDU protection/unprotection calls .................... 20
2.3.1. Relationship to GSS-API ................................ 20
2.3.2. The "SE" Calls ......................................... 21
2.3.3. The "EV" Calls ......................................... 27
2.3.4. The "GP" Calls ......................................... 36
2.4. Special-Purpose calls .................................... 47
2.4.1. Relationship to GSS-API ................................ 47
2.4.2. IDUP_Form_Complete_PIDU ................................ 48
2.5. Support calls ............................................ 49
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2.5.1. Relationship to GSS-API ................................ 49
2.5.2. IDUP_Acquire_Cred_With_Auth ............................ 49
2.5.3. IDUP_Get_Token_Details ................................. 50
2.5.4. IDUP_Get_Policy_Info ................................... 53
2.5.5. IDUP_Cancel_Multibuffer_Op ............................. 55
3. Related Activities ......................................... 55
4. Acknowledgments ............................................ 56
5. Security Considerations .................................... 56
6. References ........................................... 56
7. Author's Address ........................................... 56
Appendix A Mechanism-Independent Token Format ................. 57
Appendix B Examples of IDUP Use ............................... 58
Full Copyright Statement ....................................... 70
1. IDUP-GSS-API Characteristics and Concepts
The paradigm within which IDUP-GSS-API operates is as follows. An
IDUP-GSS-API caller is any application that works with IDUs, calling
on IDUP-GSS-API in order to protect its IDUs with services such as
data origin authentication with integrity (DOA), confidentiality with
integrity (CONF), and/or support for non-repudiation (e.g., evidence
generation, where "evidence" is information that either by itself, or
when used in conjunction with other information, is used to establish
proof about an event or action (note: the evidence itself does not
necessarily prove truth or existence of something, but contributes to
establish proof) -- see [ISO/IEC] for fuller discussion regarding
evidence and its role in various types of non-repudiation). An
IDUP-GSS-API caller passes an IDU to, and accepts a token from, its
local IDUP-GSS-API implementation, transferring the resulting
protected IDU (P-IDU) to a peer or to any storage medium. When a P-
IDU is to be "unprotected", it is passed to an IDUP-GSS-API
implementation for processing. The security services available
through IDUP-GSS-API in this fashion are implementable over a range
of underlying mechanisms based on secret-key and/or public-key
cryptographic technologies.
During the protection operation, the input IDU buffers may be
modified (for example, the data may be encrypted or encoded in some
way) or may remain unchanged. In any case, the result is termed a
"M-IDU" (Modified IDU) in order to distinguish it from the original
IDU. Depending on the desire of the calling application and the
capabilities of the underlying IDUP mechanism, the output produced by
the protection processing may or may not encapsulate the M-IDU. Thus,
the P-IDU may be the contents of a single output parameter (if
encapsulation is done) or may be the logical concatenation of an
unencapsulated token parameter and a M-IDU parameter (if
encapsulation is not done). In the latter case, the protecting
application may choose whatever method it wishes to concatenate or
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combine the unencapsulated token and the M-IDU into a P-IDU, provided
the unprotecting application knows how to de-couple the P-IDU back
into its component parts prior to calling the IDUP unprotection set
of functions.
It is expected that any output buffer returned by IDUP (i.e., P-IDU
or portion thereof) is ready for immediate transmission to the
intended receiver(s) by the calling application, if this is desired.
In other words, an application wishing to transmit data buffers as
they appear from IDUP should not be unduly restricted from doing so
by the underlying mechanism.
The IDUP-GSS-API separates the operation of initializing a security
environment (the IDUP_Establish_Env() call) from the operations of
providing per-IDU protection, for IDUs subsequently protected in
conjunction with that environment. Per-IDU protection and
unprotection calls provide DOA, CONF, evidence, and other services,
as requested by the calling application and as supported by the
underlying mechanism.
The following paragraphs provide an example illustrating the
dataflows involved in the use of the IDUP-GSS-API by the sender and
receiver of a P-IDU in a mechanism-independent fashion. The example
assumes that credential acquisition has already been completed by
both sides. Furthermore, the example does not cover all possible
options available in the protection/unprotection calls.
The sender first calls IDUP_Establish_Env() to establish a
security environment. Then, for the IDU to be protected the
sender calls the appropriate protection calls (SE, EV, or GP) to
perform the IDU protection. The resulting P-IDU, which may
(depending on whether or not encapsulation was chosen/available)
be either the token itself or the logical concatenation of the
token and the M-IDU, is now ready to be sent to the target. The
sender then calls IDUP_Abolish_Env() to flush all environment-
specific information.
The receiver first calls IDUP_Establish_Env() to establish a
security environment in order to unprotect the P-IDU. Then, for
the received P-IDU the receiver calls the appropriate unprotection
calls (SE, EV, or GP (known a priori, or possibly determined
through the use of the IDUP_Get_token_details call)) to perform
the P-IDU unprotection. The receiver then calls
IDUP_Abolish_Env() to flush all environment-specific information.
It is important to note that absolutely no synchronization is implied
or expected between the data buffer size used by the sender as input
to the protection calls, the data buffer size used by the receiver as
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input to the unprotection calls, and the block sizes required by the
underlying protection algorithms (integrity and confidentiality). All
these sizes are meant to be independent; furthermore, the data buffer
sizes used for the protection and unprotection calls are purely a
function of the local environment where the calls are made.
The IDUP-GSS-API design assumes and addresses several basic goals,
including the following.
Mechanism independence: The IDUP-GSS-API defines an interface to
cryptographically implemented security services at a generic level
which is independent of particular underlying mechanisms. For
example, IDUP-GSS-API-provided services can be implemented by
secret-key technologies or public-key approaches.
Protocol environment independence: The IDUP-GSS-API is independent
of the communications protocol suites which may be used to
transfer P-IDUs, permitting use in a broad range of protocol
environments.
Protocol association independence: The IDUP-GSS-API's security
environment construct has nothing whatever to do with
communications protocol association constructs, so that IDUP-GSS-
API services can be invoked by applications, wholly independent of
protocol associations.
Suitability for a range of implementation placements: IDUP-GSS-API
clients are not constrained to reside within any Trusted Computing
Base (TCB) perimeter defined on a system where the IDUP-GSS-API is
implemented; security services are specified in a manner suitable
for both intra-TCB and extra-TCB callers.
1.1. IDUP-GSS-API Constructs
This section describes the basic elements comprising the IDUP-GSS-
API.
1.1.1. Credentials
Credentials in IDUP-GSS-API are to be understood and used as
described in GSS-API RFC-2078">[RFC-2078].
1.1.2. Tokens
Tokens in IDUP-GSS-API are to be understood and used as described in
GSS-API RFC-2078">[RFC-2078] with the exception that there are no context-level
tokens generated by IDUP-GSS-API. The IDUP-GSS-API token may
(depending on the underlying mechanism) encapsulate the M-IDU or may
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be logically concatenated with the M-IDU prior to transfer to a
target; furthermore, for some evidence services the token may be sent
independently of any other data transfer.
1.1.3. Security Environment
The "security environment" in IDUP-GSS-API is entirely different from
the concept of security contexts used in GSS-API RFC-2078">[RFC-2078]. Here, a
security environment exists within a calling application (that is, it
is purely local to the caller) for the purpose of protecting or
unprotecting one or more IDUs using a particular caller credential or
set of credentials. In GSS-API, on the other hand, a security
context exists between peers (the initiator and the target) for the
purpose of protecting, in real time, the data that is exchanged
between them. Although they are different concepts, the env_handle
in IDUP-GSS-API is similar to the context_handle in GSS-API in that
it is a convenient way of tying together the entire process of
protecting or unprotecting one or more IDUs using a particular
underlying mechanism. As with the GSS-API security contexts, a
caller can initiate and maintain multiple environments using the same
or different credentials.
1.1.4. Mechanism Types
Mechanism types in IDUP-GSS-API are to be understood and used as
described in GSS-API RFC-2078">[RFC-2078].
1.1.5. Naming
Naming in IDUP-GSS-API is to be understood and used as described in
GSS-API RFC-2078">[RFC-2078].
1.1.6. Channel Bindings
The concept of channel bindings discussed in GSS-API RFC-2078">[RFC-2078] is
not relevant to the IDUP-GSS-API.
1.2. IDUP-GSS-API Features and Issues
This section describes aspects of IDUP-GSS-API operations and of the
security services which the IDUP-GSS-API provides. It also provides
commentary on design issues.
1.2.1. Status Reporting
Status reporting in IDUP-GSS-API is to be understood and used as
described in GSS-API RFC-2078">[RFC-2078], with the addition of a number of
IDUP-specific status codes. Descriptions of the major_status codes
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used in IDUP are provided in Table 1. Codes that are informatory
(i.e., that do not cause the requested operation to fail) are
indicated with the symbol "(I)".
As with GSS-API, minor_status codes, which provide more detailed
status information than major_status codes, and which may include
status codes specific to the underlying security mechanism, are not
specified in this document.
Table 1: IDUP-GSS-API Major Status Codes
GSS_S_BAD_MECH indicates that a mech_type unsupported by the
IDUP_GSS-API implementation was requested, causing the environment
establishment operation to fail.
GSS_S_BAD_QOP indicates that the provided qop_alg value is not
recognized or supported for the environment.
GSS_S_BAD_MIC indicates that the received P-IDU contains an
incorrect integrity field (e.g., signature or MAC) for the data.
GSS_S_COMPLETE indicates that the requested operation was
successful.
GSS_S_CREDENTIALS_EXPIRED indicates that the credentials
associated with this operation have expired, so that the requested
operation cannot be performed.
GSS_S_DEFECTIVE_CREDENTIAL indicates that consistency checks
performed on the credential structure referenced by
claimant_cred_handle failed, preventing further processing from
being performed using that credential structure.
GSS_S_DEFECTIVE_TOKEN indicates that consistency checks performed
on the received P-IDU failed, preventing further processing from
being performed.
GSS_S_FAILURE indicates that the requested operation could not be
accomplished for reasons unspecified at the IDUP-GSS-API level,
and that no interface-defined recovery action is available.
GSS_S_NO_CRED indicates that no environment was established,
either because the input cred_handle was invalid or because the
caller lacks authorization to access the referenced credentials.
IDUP_S_BAD_DOA_KEY indicates that the key used to provide IDU data
origin auth. / integ. has either expired or been revoked.
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IDUP_S_BAD_ENC_IDU indicates that decryption of the received IDU
cannot be completed because the encrypted IDU was
invalid/defective (e.g., the final block was short or had
incorrect padding).
IDUP_S_BAD_KE_KEY indicates that the key used to establish a key
for confidentiality purposes between originator and target has
either expired or been revoked.
IDUP_S_BAD_TARG_INFO indicates that the full set of supplied
information regarding the target(s) is invalid or is insufficient
for the protection of an IDU, so P-IDU cannot be created.
IDUP_S_DEFECTIVE_VERIF indicates that consistency checks performed
on Service_Verification_Info failed, preventing further processing
from being performed with that parameter.
IDUP_S_ENCAPSULATION_UNAVAIL (I) indicates that the underlying
mechanism does not support encapsulation of the M-IDU into the
token.
IDUP_S_INAPPROPRIATE_CRED indicates that the credentials supplied
do not contain the information necessary for P-IDU unprotection.
IDUP_S_INCOMPLETE (I) indicates that the unprotection of the P-IDU
is not yet complete (i.e., a determination cannot yet be made on
the validity of the P-IDU). The application should call
IDUP_Form_Complete_PIDU and then should call this function again
with the complete P-IDU.
IDUP_S_INCONSISTENT_PARAMS indicates that the supplied parameters
are inconsistent (e.g., only one or the other of two parameters
may be supplied, but both have been input).
IDUP_S_MORE_OUTBUFFER_NEEDED (I) indicates that the output buffer
supplied is too small to hold the generated data. The application
should continue calling this routine (until GSS_S_COMPLETE is
returned) in order to get all remaining output data.
IDUP_S_MORE_PIDU_NEEDED (I) indicates that not enough of the P-IDU
has been input yet for the completion of StartUnprotect. The
application should call this routine again with another buffer of
P-IDU in partial(initial)_pidu_buffer.
IDUP_S_NO_ENV indicates that no valid environment was recognized
for the env_handle provided.
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IDUP_S_NO_MATCH indicates that Service_Verification_Info (or
evidence_check) and the P-IDU to be verified do not match.
IDUP_S_REQ_TIME_SERVICE_UNAVAIL indicates that the time service
requested (TTIME or UTIME) is not available in the environment.
IDUP_S_SERVICE_UNAVAIL indicates that the underlying mechanism
does not support the service requested.
IDUP_S_SERV_VERIF_INFO_NEEDED (I) indicates that the
Service_Verification_Info parameter bundle must be input in order
for service verification to proceed. The output parameter
service_verification_info_id contains an identifier which may be
used by the calling application to locate the necessary
information.
IDUP_S_UNKNOWN_OPER_ID indicates that the input prot_oper_id value
is not recognized or supported in the underlying mechanism.
1.2.2. Per-IDU Security Service Availability
Per-IDU security service availability in IDUP-GSS-API is to be
understood and used as described in GSS-API RFC-2078">[RFC-2078], with the
exception that combinations of services requested by the calling
application and supported by the underlying mechanism may be applied
simultaneously to any IDU (true for both the SE and the EV calls, but
true in the fullest sense for the GP calls).
GSS-API callers desiring per-message security services should check
the relevant service OBJECT IDs at environment establishment time to
ensure that what is available in the established environment is
suitable for their security needs.
1.2.3. Per-IDU Replay Detection and Sequencing
The concept of per-IDU replay detection and sequencing discussed in
GSS-API RFC-2078">[RFC-2078] is not relevant to the IDUP-GSS-API.
1.2.4. Quality of Protection
The concept of QOP control in IDUP-GSS-API is to be understood
essentially as described in GSS-API RFC-2078">[RFC-2078]. However, the actual
description and use of the QOP parameter is given as follows.
The qop_algs parameter for IDUP is defined to be a 32-bit unsigned
integer with the following bit-field assignments:
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31 (MSB) (LSB) 0
----------------------------------------------
| U(19) | TS(5) | IA(4) | MA(4) |
----------------------------------------------
where
U is a 19-bit Unspecified field (available for future
use/expansion) -- must be set to zero;
TS is a 5-bit Type Specifier (a semantic qualifier whose value
specifies the type of algorithm which may be used to protect the
corresponding IDU -- see below for details);
IA is a 4-bit field enumerating Implementation-specific
Algorithms; and
MA is a 4-bit field enumerating Mechanism-defined Algorithms.
The interpretation of the qop_algs parameter is as follows. The MA
field is examined first. If it is non-zero then the algorithm used
to protect the IDU is the mechanism-specified algorithm corresponding
to that integer value.
If MA is zero then IA is examined. If this field value is non-zero
then the algorithm used to protect the IDU is the implementation-
specified algorithm corresponding to that integer value. Note that
use of this field may hinder portability since a particular value may
specify one algorithm in one implementation of the mechanism and may
not be supported or may specify a completely different algorithm in
another implementation of the mechanism.
Finally, if both MA and IA are zero then TS is examined. A value of
zero for TS specifies the default algorithm for the established
mechanism. A non-zero value for TS corresponds to a particular
algorithm qualifier and selects any algorithm from the mechanism
specification which satisfies that qualifier (which actual algorithm
is selected is an implementation choice; the calling application need
not be aware of the choice made).
The following TS values (i.e., algorithm qualifiers) are specified;
other values may be added in the future.
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When qop_algs is used to select a confidentiality algorithm:
00000 (0) = default confidentiality algorithm
00001 (1) = IDUP_SYM_ALG_STRENGTH_STRONG
00010 (2) = IDUP_SYM_ALG_STRENGTH_MEDIUM
00011 (3) = IDUP_SYM_ALG_STRENGTH_WEAK
11111 (31) = IDUP_NO_CONFIDENTIALITY
When qop_algs is used to select a DOA/integrity algorithm:
00000 (0) = default integrity algorithm
00001 (1) = IDUP_INT_ALG_DIG_SIGNATURE
(integrity provided through a digital signature)
00010 (2) = IDUP_INT_ALG_NON_DIG_SIGNATURE
(integrity without a dig. sig. (e.g., with a MAC))
11111 (31) = IDUP_NO_INTEGRITY
Clearly, qualifiers such as strong, medium, and weak are debatable
and likely to change with time, but for the purposes of this version
of the specification we define these terms as follows. A
confidentiality algorithm is "weak" if the effective key length of
the cipher is 40 bits or less; it is "medium-strength" if the
effective key length is strictly between 40 and 80 bits; and it is
"strong" if the effective key length is 80 bits or greater.
("Effective key length" describes the computational effort required
to break a cipher using the best-known cryptanalytic attack against
that cipher.)
A five-bit TS field allows up to 30 qualifiers for each of
confidentiality and integrity (since "0" is reserved for "default"
and "31" is reserved for "none", as shown above). This document
specifies three for confidentiality and two for integrity, leaving a
lot of room for future specification. Suggestions of qualifiers such
as "fast", "medium-speed", and "slow" have been made, but such terms
are difficult to quantify (and in any case are platform- and
processor-dependent), and so have been left out of this initial
specification. The intention is that the TS terms be quantitative,
environment-independent qualifiers of algorithms, as much as this is
possible.
Use of the qop_algs parameter as defined above is ultimately meant to
be as follows.
- TS values are specified at the IDUP-GSS-API level and are
therefore portable across mechanisms. Applications which know
nothing about algorithms are still able to choose "quality" of
protection for their message tokens.
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- MA values are specified at the mechanism level and are therefore
portable across implementations of a mechanism.
- IA values are specified at the implementation level (in user
documentation, for example) and are therefore typically non-
portable. An application which is aware of its own mechanism
implementation and the mechanism implementation of its intended
P-IDU recipient, however, is free to use these values since they
will be perfectly valid and meaningful for protecting IDUs between
those entities.
The receiver of a P-IDU must pass back to its calling application (in
IDUP_Start_Unprotect()) a qop_algs parameter with all relevant fields
set. For example, if triple-DES has been specified by a mechanism as
algorithm 8, then a receiver of a triple-DES-protected P-IDU must
pass to its application (TS=1, IA=0, MA=8). In this way, the
application is free to read whatever part of the qop_algs parameter
it understands (TS or IA/MA).
1.2.5. The Provision of Time
IDUP mechanisms should make provision in their protocols for the
carrying of time information from originator to target(s). That is,
a target (a legitimate recipient) should get some indication during
unprotection regarding the time at which the protection operation
took place. This is particularly important if the mechanism offers
non-repudiation services because in some cases evidence verification
may only be achievable if the time at which the evidence was
generated is known.
Depending upon the platform and resources available to the
implementation, an IDUP environment may have access to a source of
trusted (secure) time, untrusted (local) time, both kinds of time, or
no time. OBJECT IDs indicating such availability are returned by the
IDUP_Establish_Env() call. When starting a protection operation, an
application may specify which time services it wishes to have applied
to the IDU. Similarly, for unprotection, an application may specify
which kind of time (if any) to consult when the validity of the P-IDU
is to be established. Specifying both kinds of time is interpreted
to mean that the calling application does not care which kind of time
is used.
The IDUP calls which use a time parameter specify the type of that
parameter to be INTEGER. This INTEGER is defined in all cases to be
the number of seconds which have elapsed since midnight, January 1,
1970, coordinated universal time.
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2. Interface Descriptions
This section describes the IDUP-GSS-API's operational interface,
dividing the set of calls offered into five groups. Credential
management calls are related to the acquisition and release of
credentials by API callers. Environment-level calls are related to
the management of the security environment by an API caller. Per-IDU
calls are related to the protection or unprotection of individual
IDUs in established security environments. Special-purpose calls
deal with unusual or auxiliary evidence generation/verification
requirements. Support calls provide extra functions useful to IDUP-
GSS-API callers. Table 2 groups and summarizes the calls in tabular
fashion.
Table 2: IDUP-GSS-API Calls
CREDENTIAL MANAGEMENT
(see the calls given in Section 2.1 of GSS-API RFC-2078">[RFC-2078])
ENVIRONMENT-LEVEL CALLS
IDUP_Establish_Env
IDUP_Abolish_Env
IDUP_Inquire_Env
PER-IDU CALLS
SE (SIGN,ENCRYPT) CALLS
IDUP_SE_SingleBuffer_Protect
IDUP_SE_SingleBuffer_Unprotect
IDUP_SE_MultiBuffer_StartProtect
IDUP_SE_MultiBuffer_EndProtect
IDUP_SE_MultiBuffer_StartUnprotect
IDUP_SE_MultiBuffer_EndUnprotect
IDUP_SE_Process_Buffer
EV (EVIDENCE) CALLS
IDUP_EV_SingleBuffer_Generate
IDUP_EV_SingleBuffer_Verify
IDUP_EV_MultiBuffer_StartGenerate
IDUP_EV_MultiBuffer_EndGenerate
IDUP_EV_MultiBuffer_StartVerify
IDUP_EV_MultiBuffer_EndVerify
IDUP_EV_Process_Buffer
GP (GENERAL PROTECTION) CALLS
IDUP_Start_Protect
IDUP_Protect
IDUP_End_Protect
IDUP_Start_Unprotect
IDUP_Unprotect
IDUP_End_Unprotect
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SPECIAL-PURPOSE CALLS (might not be supported by all mechanisms)
IDUP_Form_Complete_PIDU
SUPPORT CALLS
IDUP_Acquire_cred_with_auth
IDUP_Get_Token_Details
IDUP_Get_Policy_Info
IDUP_Cancel_Multibuffer_Op
(see also the calls given in Section 2.4 of GSS-API RFC-2078">[RFC-2078])
In terms of conformance to this specification, IDUP-GSS-API
implementations must support the credential management calls, the
environment-level calls, some subset of the per-IDU calls, and the
support calls (except where explicitly stated otherwise in Section
2.5). The subset of per-IDU calls supported will depend upon the
underlying mechanisms supported and will typically be the SE calls,
or the EV calls, or both. As stated in Section 2.3.2.1,
implementations are encouraged to support the more powerful GP calls
to anticipate the future needs of applications developers, but this
is not required for conformance.
2.1. Credential management calls
2.1.1. Relationship to GSS-API
Credential management in IDUP-GSS-API is to be understood and used as
described in GSS-API RFC-2078">[RFC-2078]. The calls given in Section 2.1 of
GSS-API (including all associated parameters) are unchanged, although
the interpretation of the cred_usage parameter in the GSS-API calls
for IDUP purposes is as follows.
ENCRYPT_ONLY 8
DECRYPT_ONLY 16
SIGN_ONLY 32
VERIFY_ONLY 64
The values above may be logically OR'ed together in any desired
combination to restrict credential usage (where OR'ing all values
results in NO_RESTRICTION). Future possible values for this
parameter are for further study.
The call IDUP_Acquire_cred_with_auth has been added as a support call
in this specification to permit authenticated credential acquirement;
see Section 2.5.2 for details.
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2.2. Environment-level calls
This group of calls is devoted to the establishment and management of
an environment for the purpose of IDU protection and unprotection.
Before protecting or unprotecting any IDU, an application must call
IDUP_Establish_Env() to initialize environment information and select
the underlying IDUP-GSS mechanism to be used. A series of protection
or unprotection calls is made to process each IDU, the protection
calls resulting in a P-IDU for each. Finally, IDUP_Abolish_Env() is
called to flush all environment information.
Semantically, acquiring credentials and establishing an environment
is (in many cases) analogous to logging in to a system -- it
authenticates a local user to the system and gives that user access
to a set of operations which can be performed.
2.2.1. Relationship to GSS-API
The set of calls described in this section is used in place of the
calls described in Section 2.2 of GSS-API RFC-2078">[RFC-2078], since those
calls are specific to a session-oriented environment.
2.2.2. IDUP_Establish_Env call
Inputs: o claimant_cred_handle CREDENTIAL HANDLE,
-- NULL parameter specifies "use default"
o req_mech_type OBJECT IDENTIFIER,
-- NULL parameter specifies "use default"
o req_environmentPolicies EnvironmentPolicies,
-- NULL parameter specifies "use default"
o req_services SET OF OBJECT IDENTIFIER,
-- GSS_C_NO_OID_SET requests full set of services available
-- for req_mech_type
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o env_handle ENVIRONMENT HANDLE,
o actual_mech_type OBJECT IDENTIFIER,
-- actual mechanism always indicated, never NULL
o actual_environmentPolicies EnvironmentPolicies,
-- actual values always indicated, never NULL
o ret_services SET OF OBJECT IDENTIFIER,
Return major_status codes:
o GSS_S_COMPLETE
-- environment-level information was successfully initialized,
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-- and IDU / P-IDU processing can begin.
o GSS_S_DEFECTIVE_CREDENTIAL
o GSS_S_NO_CRED
o GSS_S_CREDENTIALS_EXPIRED
-- the credentials provided through claimant_cred_handle are
-- no longer valid, so environment cannot be established.
o GSS_S_BAD_MECH
o GSS_S_FAILURE
The following structures are defined to facilitate environment policy
input and output:
EnvironmentPolicies ::= SEQUENCE {
confPolicy [0] PolicyAndTime OPTIONAL,
-- NULL parameter (on input) specifies "use default"
integPolicy [1] PolicyAndTime OPTIONAL,
-- NULL parameter (on input) specifies "use default"
evidencePolicy [2] PolicyAndTime OPTIONAL }
-- NULL parameter (on input) specifies "use default"
PolicyAndTime ::= SEQUENCE {
policy OBJECT IDENTIFIER,
-- this environment-level policy identifier is separate from
-- the policy provisions connected with credentials, if they exist
time INTEGER
-- on input: the policy rules available at the specified time
-- on output: the time at which the policy rules came into effect
-- (defined to be the number of seconds elapsed since midnight,
-- January 1, 1970, coordinated universal time)
endTime INTEGER OPTIONAL }
-- on input: unused
-- on output: the expiration time of the given policy rules
This routine is used by an application which protects or unprotects
IDUs. Using information in the credentials structure referenced by
claimant_cred_handle, IDUP_Establish_Env() initializes the data
structures required to protect or unprotect IDUs. The
claimant_cred_handle, if non-NULL, must correspond to a valid
credentials structure.
This routine returns an env_handle for all future references to this
environment; when protection, unprotection, or IDUP_Abolish_Env()
calls are made, this handle value will be used as the input
env_handle argument. It is the caller's responsibility to establish
a communications path to the intended recipients of the P-IDU, and to
transmit the P-IDU to those recipients over that path. This may
occur subsequent to the IDUP_Abolish_Env() call.
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The req_services parameter may be used by the calling application to
request that data origin authentication with integrity,
confidentiality with integrity, evidence generation, and/or evidence
verification services be available in the established environment.
Requests can also be made for "trusted" or "untrusted" time services.
Requesting evidence generation or verification indicates that the
calling application may wish to generate or verify evidence
information for non-repudiation purposes (note: an IDU protector may
request that a flag be inserted into a P-IDU asking a recipient to
provide an evidence of the type "non-repudiation of delivery";
however, the IDUP-GSS-API cannot by itself guarantee that the
evidence will be sent because there is no way to force a target to
send an evidence_token back to the IDU protector).
Not all features will be available in all underlying mech_types; the
returned value of ret_services indicates, as a function of mech_type
processing capabilities and the initiator-provided input OBJECT IDs,
the set of features which will be available in the environment. The
value of this parameter is undefined unless the routine's
major_status indicates COMPLETE. Failure to provide the precise set
of services desired by the caller does not cause environment
establishment to fail; it is the caller's choice to abolish the
environment if the service set provided is unsuitable for the
caller's use. The returned mech_type value indicates the specific
mechanism employed in the environment and will never indicate the
value for "default".
The following OBJECT IDs are defined for protection and unprotection
services (the OBJECT ID iso.org.dod.internet.security.services,
1.3.6.1.5.7, has been assigned by IANA, and some of the security
services under that node are assigned as shown below). It is
recognized that this list may grow over time.
PER_CONF = { 1.3.6.1.5.7.1.1 }
-- perform data confidentiality (i.e., encrypt data)
PER_CONF_FULL = { 1.3.6.1.5.7.1.3 }
-- perform full confidentiality (i.e., encrypt data and sig)
-- (may be used only when PER_DOA is requested simultaneously)
PER_DOA = { 1.3.6.1.5.7.3.1 }
-- perform data origin authentication with data integrity
PER_DOA_CIPH = { 1.3.6.1.5.7.3.3 }
-- perform DOA with DI over ciphertext (rather than plaintext)
-- (may be used only when PER_CONF is requested simultaneously)
PER_POO = { 1.3.6.1.5.7.4.1 }
-- perform (i.e., create) non-repudiable "proof of origin"
PER_POD = { 1.3.6.1.5.7.4.3 }
-- perform (i.e., create) non-repudiable "proof of delivery"
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REC_CONF = { 1.3.6.1.5.7.1.2 }
-- receive data confidentiality (i.e., decrypt data)
REC_CONF_FULL = { 1.3.6.1.5.7.1.4 }
-- receive full confidentiality (i.e., decrypt data and sig)
-- (may be used only when REC_DOA is received simultaneously)
REC_DOA = { 1.3.6.1.5.7.3.2 }
-- receive / verify DOA with data integrity
REC_DOA_CIPH = { 1.3.6.1.5.7.3.4 }
-- verify DOA with DI over ciphertext (rather than plaintext)
-- (may be used only when PER_CONF is received simultaneously)
REC_POO = { 1.3.6.1.5.7.4.2 }
-- receive / verify "proof of origin"
REC_POD = { 1.3.6.1.5.7.4.4 }
-- receive / verify "proof of delivery"
TTIME = { 1.3.6.1.5.7.7.1 }
-- trusted time availability
UTIME = { 1.3.6.1.5.7.7.2 }
-- untrusted time availability
The PER_CONF return value (in the ret_services paramater) indicates
whether the environment supports confidentiality services, and so
informs the caller whether or not a request for encryption can be
honored. In similar fashion, the PER_DOA return value indicates
whether DOA services are available in the established environment,
and the PER_POO and PER_POD return values indicate whether evidence
generation services are available. The TTIME and UTIME values
indicate whether trusted time and untrusted time are available for
protection / unprotection services.
Note that, unlike a GSS "context", an IDUP environment does not have
an explicit lifetime associated with it. Instead, it relies on the
lifetime of the calling entity's credential (set by the caller in the
GSS_Acquire_cred() call). When the credential expires (or is
explicitly deleted in any other way), no new operations are allowed
in the IDUP environment (although operations which have begun, such
as the Protection set of calls, can be taken to completion).
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2.2.3. IDUP_Abolish_Env call
Input:
o env_handle ENVIRONMENT HANDLE
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
Return major_status codes:
o GSS_S_COMPLETE
-- the relevant environment-specific information was flushed.
o IDUP_S_NO_ENV
o GSS_S_FAILURE
This call is made to flush environment-specific information. (Once an
environment is established, cached credential and environment-related
info. is expected to be retained until an IDUP_Abolish_Env() call is
made or until the cred. lifetime expires.) Attempts to perform IDU
processing on a deleted environment will result in error returns.
2.2.4. IDUP_Inquire_Env call
Input:
o env_handle ENVIRONMENT HANDLE,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o mech_type OBJECT IDENTIFIER,
-- the mechanism supporting this environment
o environmentPolicies EnvironmentPolicies,
-- the environment policies in effect
o ret_services SET OF OBJECT IDENTIFIER,
Return major_status codes:
o GSS_S_COMPLETE
-- referenced environment is valid and mech_type and other return
-- values describe the characteristics of the environment.
o GSS_S_CREDENTIALS_EXPIRED
o IDUP_S_NO_ENV
o GSS_S_FAILURE
This routine provides environment-related information to the caller.
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2.3. Per-IDU calls
This group of calls is used to perform IDU protection and
unprotection processing on an established IDUP environment. Some of
these calls may block pending network interactions (depending on the
underlying mechanism in use). These calls may be invoked by an IDU's
protector or by the P-IDU's recipient. Members of this group form
pairs; the output from the protection types of calls is typically
meant to be input to the unprotection types of calls.
The per-IDU calls can support caller-requested data origin
authentication with data integrity, confidentiality with data
integrity, evidence, and evidence-requested-from-target services.
The protection operations output a token which encapsulates all the
information required to unprotect the IDU. The token is passed to
the target (possibly separate from the M-IDU) and is processed by the
unprotection calls at that system. Unprotection performs
decipherment, DOA verification, evidence verification, or
notification of evidence requested, as required.
Each of the two main operations (protection and unprotection) may be
separated into three parts: "Start_Operation"; "Operation" (which
may be called once for each buffer of input data); and
"End_Operation". This separation is available for the case where the
IDU or P-IDU is to be processed one buffer at a time.
"Start_Operation" allows the caller to specify or retrieve the
appropriate "Quality" used during the processing. "Operation" is
concerned with the processing itself, receiving a buffer of input
data and potentially returning a buffer of output data.
"End_Operation" performs any required clean-up and creates the
appropriate token or states whether the input token was verified.
If the IDU or P-IDU is wholly contained in a single buffer, the
three-part protection/unprotection processing need not be done.
Instead, protection or unprotection can be accomplished using only a
single call, simplifying application code.
2.3.1. Relationship to GSS-API
The set of calls described in this section is used in place of the
calls GSS_GetMIC(), GSS_VerifyMIC, GSS_Wrap(), and GSS_Unwrap() which
are specified in RFC-2078">[RFC-2078], since those calls are specific to a
session-oriented environment.
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2.3.2. The "SE" Calls
2.3.2.1. IDUP_SE Purpose
The "SE" group of calls provides a very simple, high-level interface
to underlying IDUP mechanisms when application developers need access
only to signature and encryption protection/unprotection services.
It includes both the single-buffer and multiple-buffer IDU cases and
can be used for signing only, encrypting only, signing and encrypting
(in either order, and with or without visibility of the resulting
signature), and "clear signing" (where the data is not modified in
any way and the signature itself is returned as a separate item).
[Note that encapsulation occurs in all cases except for clear
signing, so that these calls provide functionality similar to the
GSS_Wrap call.]
Note that the term "signing" is used in its most generic sense, not
necessarily implying the use of public-key techniques. This concept
has also been called "sealing" in other contexts (e.g., in other
standardization efforts).
The SE calls may be viewed by mechanism implementors as an "API" to
the more powerful GP calls defined later and so may be implemented as
simple mapping functions to those calls (when those optional calls
are supported). Application callers, on the other hand, may find
that the SE calls are all they currently need for many environments.
At some time in the future when they have need of non-repudiation or
"directed receipts" types of services, they may consider using the EV
calls (or the GP calls -- when these are supported -- if complex and
sophisticated combinations of services are required). To assist in
this migration path, mechanism implementors are encouraged to support
the full set of IDUP calls (i.e., the SE, EV, and GP calls) even
though some calling applications will only use the SE calls in the
short term.
2.3.2.2. IDUP_SE Parameter Bundles
The concept of "parameter bundles" is used in the calls presented in
the following subsections in order to simplify their presentation and
clarify their intended purpose and use. See Section 2.3.4.1 for a
more complete description of parameter bundles.
The following parameter bundles are used in the "SE" protection and
unprotection sets of calls.
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o Protect_Options PARAMETER BUNDLE
o protect_operation INTEGER {
sign_only (0),
encrypt_only (1),
sign_and_encrypt (2),
-- let mechanism choose order (and readability of signature)
sign_then_encrypt_data (3),
-- sign, then encrypt plaintext (leaving signature in clear)
sign_then_encrypt_full (4),
-- sign, then encrypt everything (including signature)
encrypt_then_sign (5),
-- encrypt, then sign the ciphertext
clear_sign_only (6)
} OPTIONAL,
o protect_oper_oid OBJECT IDENTIFIER OPTIONAL,
-- may be used in place of above parameter if OID is known
o sign_qop_alg UNSIGNED INTEGER,
o sign_qop_algID AlgorithmIdentifier, --overrides sign_qop_alg
o enc_qop_alg UNSIGNED INTEGER,
o enc_qop_algID AlgorithmIdentifier, --overrides enc_qop_alg
o idu_type_string OCTET STRING,
-- type of the IDU ("data", "e-mail doc", MIME type, etc.)
o pidu_type_string OCTET STRING,
o mech_indep_encap_req BOOLEAN -- (see Appendix A)
o PIDU_Information PARAMETER BUNDLE
o protect_options Protect_Options,
o originator_name INTERNAL NAME,
o originator_role Originator_Role, -- (see Section 2.3.4.1)
o protection_time INTEGER,
o Bad_Target_Name PARAMETER BUNDLE, -- same as in Section 2.3.3.2
o bad_targ_name INTERNAL NAME,
o bad_targ_status INTEGER,
-- a status flag giving the reason for rejection of the name
-- in bad_targ_name. Specified reasons include:
-- SYNTAX_INVALID (0) the syntax of the name is invalid;
-- NAME_UNRECOGNIZED (1) the name is not recognized;
-- NAME_AMBIGUOUS (2) the name cannot be resolved;
-- ACCESS_DENIED (3) access to this target is denied;
-- CERTIFICATE_NOT_FOUND (4) the encryption certificate of the
target could not be found.
o Target_Info PARAMETER BUNDLE, -- same as in Section 2.3.3.2
o targ_names SET OF INTERNAL NAME,
o bad_targ_count INTEGER,
o bad_target_names SET OF Bad_Target_Name,
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2.3.2.3. IDUP_SE major_status codes
The following major_status return codes are defined for the "SE"
calls in this section:
o GSS_S_COMPLETE
o IDUP_S_MORE_OUTBUFFER_NEEDED
-- returned (by any SE call) to indicate that there is more output
-- data than can fit into the supplied buffers. The application
-- should save the returned data and call again to retrieve the
-- remaining output.
o IDUP_S_MORE_PIDU_NEEDED
-- indicates that more PIDU data is needed for the StartUnprotect
-- operation (e.g., so that PIDU_Information or initial_idu_buffer
-- may be returned).
o IDUP_S_INCONSISTENT_PARAMS
o GSS_S_CREDENTIALS_EXPIRED
o IDUP_S_NO_ENV
o GSS_S_BAD_QOP
o GSS_S_FAILURE
If Target_Info is used as an input parameter (e.g., if an encryption
operation is being performed), the following major_status return code
is also defined:
o IDUP_S_BAD_TARG_INFO
Note for this return code that if one or more of the targets in
targ_names cannot be used as a valid recipient of the P-IDU, these
names will be returned in bad_targ_names (with associated status
codes in bad_targ_status). As long as at least one of the targets
can be used, however, this does not cause this call to fail (i.e.,
the failure code IDUP_S_BAD_TARG_INFO is not returned); it is the
caller's choice to discontinue IDU protection if the target set which
can be used is unsuitable for the caller's purposes.
2.3.2.4. IDUP_SE_SingleBuffer_Protect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o Protect_Options PARAMETER BUNDLE,
o Target_Info PARAMETER BUNDLE,
o idu_buffer OCTET STRING
o additional_protection BOOLEAN
-- TRUE if idu_buffer is the output of a previous protection
-- operation (i.e., if this is the second (or higher) in a
-- series of SE/EV protection calls)
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Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o pidu_buffer OCTET STRING,
o sig_token OCTET STRING
-- used if Protect_Options is clear_sign_only
Using the security environment referenced by env_handle, encrypt
and/or sign the supplied IDU. If "clear signing" is performed, the
signature will be returned in sig_token and pidu_buffer may be empty
(depends on underlying mechanism).
2.3.2.5. IDUP_SE_SingleBuffer_Unprotect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o pidu_buffer OCTET STRING,
-- may contain an IDU if sig_token is non-NULL (i.e., if
-- clear_sign_only protection was applied)
o sig_token OCTET STRING
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o idu_buffer OCTET STRING,
-- may be empty if clear_sign_only protection was applied (depends
-- on underlying mechanism)
o PIDU_Information PARAMETER BUNDLE
o additional_unprotection BOOLEAN
-- TRUE if idu_buffer should be input to another unprotection
-- operation (i.e., if this should not be the last in a series
-- of SE/EV unprotection calls)
Using the security environment referenced by env_handle, decrypt
and/or verify the supplied PIDU and return the contained IDU along
with all available PIDU_Information.
2.3.2.6. IDUP_SE_MultiBuffer_StartProtect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o Protect_Options PARAMETER BUNDLE,
o Target_Info PARAMETER BUNDLE,
o additional_protection BOOLEAN, -- (see Section 2.3.2.4)
o idu_size INTEGER -- (see Section 2.3.4.2)
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Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o initial_pidu_buffer OCTET STRING
-- may be empty (depends on underlying mechanism)
Using the security environment referenced by env_handle, initialize
the data structures required to begin the process of signing and/or
encrypting the IDU (which will be supplied in multiple buffers to the
Process_Buffer call).
2.3.2.7. IDUP_SE_MultiBuffer_EndProtect call
Inputs:
o env_handle ENVIRONMENT HANDLE
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o final_pidu_buffer OCTET STRING,
o sig_token OCTET STRING
-- used if Protect_Options was clear_sign_only
Using the security environment referenced by env_handle, complete the
protection processing on the data and place the computed output in
final_pidu_buffer and/or sig_token. Successful application of
IDUP_SE_MultiBuffer_EndProtect() does not guarantee that unprotection
can necessarily be performed successfully when the P-IDU arrives at
the target (for example, it may be damaged in transit).
2.3.2.8. IDUP_SE_MultiBuffer_StartUnprotect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o initial_pidu_buffer OCTET STRING,
o sign_qop_alg_in UNSIGNED INTEGER,
-- used if Protect_Options was clear_sign_only (and calling
-- application has prior knowledge of signing alg. applied);
-- if NULL, then sig_token must be supplied
o sig_token OCTET STRING
-- used if Protect_Options was clear_sign_only;
-- if NULL, then sign_qop_alg_in must be supplied
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o PIDU_Information PARAMETER BUNDLE,
-- returns all available information
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o initial_idu_buffer OCTET STRING
-- may be empty
Using the security environment referenced by env_handle, initialize
the data structures required to begin the process of decrypting
and/or verifying the PIDU (which will be supplied in multiple buffers
to the Process_Buffer call).
The parameters sign_qop_alg_in and sig_token should not both be
supplied (i.e., they should not both be non-NULL). If they are both
non-NULL, however, sig_token is taken to be authoritative since this
is the token created at protection time and therefore is guaranteed
to carry the information needed to unprotect.
2.3.2.9. IDUP_SE_MultiBuffer_EndUnprotect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o sig_token OCTET STRING OPTIONAL
-- used if Protect_Options was clear_sign_only and sig_token was
-- not available when StartUnprotect was called
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o PIDU_Information PARAMETER BUNDLE,
-- returns all available information
o final_idu_buffer OCTET STRING -- may be empty
o additional_unprotection BOOLEAN -- (see Section 2.3.2.5)
Using the security environment referenced by env_handle, complete the
decryption and/or verification processing on the data and place any
residual output in final_idu_buffer.
2.3.2.10. IDUP_SE_Process_Buffer call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o input_buffer OCTET STRING,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o output_buffer OCTET STRING
-- may be zero length (depends on underlying mechanism and
-- corresponding Start() call and Protect_Options value)
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Using the security environment referenced by env_handle, continue the
processing on the data in input_buffer and, if it is available, put
any resulting output data in output_buffer. The application calls
this routine over and over again with new buffers of data until it
has processed all the data buffers of the IDU/PIDU. It then calls the
appropriate End() call to complete the processing.
2.3.3. The "EV" Calls
2.3.3.1. IDUP_EV Purpose
The "EV" group of calls provides a simple, high-level interface to
underlying IDUP mechanisms when application developers need to deal
only with evidence but not with encryption or integrity services. It
includes both the single-buffer and multiple-buffer IDU cases and can
be used for the generation and verification of evidence tokens
embodying several different types of evidences.
The following list of evidence types is supported. This list is by no
means exhaustive and it is anticipated that it may be extended in
future versions of this specification.
"Non-repudiation of Origin" prevents a message creator's false
denial of creating and sending a message.
"Non-repudiation of Creation" prevents a message creator's false
denial of creating a message.
"Non-repudiation of Sender" prevents a message creator's false
denial of sending a message (that was not necessarily created by
the sender).
"Non-repudiation of Delivery" prevents a message recipient's false
denial of having received and looked at the content of a message.
"Non-repudiation of Receipt" prevents a message recipient's false
denial of having received a message (whose content was not
necessarily looked at by the recipient).
"Non-repudiation of Approval" prevents a message recipient's false
denial of having approved the content of a received message.
An evidence is provided in the form of a evidence token. Two forms of
evidence tokens are supported:
o Tokens including the associated data,
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o Tokens without included data (but with a unique reference to
the associated data).
Evidence tokens may be freely distributed. Any possessor of an
evidence token (and of the associated data, if not included in the
token) can verify the evidence if it has the appropriate credentials
which include the definition of security policies (i.e., keys alone
do not permit the verification of evidence tokens). Any holder of an
evidence token may store it (along with the associated data, if not
included in the token) for later verification.
Calls that are specific to the support of evidence include:
* Generate_token, which generates a non-repudiation token using the
current environment. The generated token may consist of:
1 - an evidence token
2 - a token containing a request for an evidence, which carries
information describing which evidence type should be generated
by the recipient(s) and sent back to some entities (that may
or may not include the sender).
3 - a token containing an evidence token which is an answer to an
evidence that has been previously requested.
4 - a token including both an evidence and a request for another
evidence to be provided.
* Verify_evidence, which verifies the evidence token using the
current environment. This operation returns a major_status code
which can be used to determine whether the evidence contained in a
token is complete (i.e., can be successfully verified (perhaps
years) later). If a token's evidence is not complete, the token can
be passed to form_complete_pidu to complete it.
Additional useful calls for evidence services include:
* IDUP_Get_token_details (see Section 2.5.3);
* IDUP_Form_Complete_PIDU (see Section 2.4.2).
2.3.3.2. IDUP_EV Parameters
The following parameter bundles are used in the "EV" protection and
unprotection sets of calls.
o Nr_Options PARAMETER BUNDLE
o evidence_type INTEGER {
no_evidence (0)
-- used when request-only token desired
proof_of_receipt (1),
proof_of_delivery (2),
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proof_of_approval (3),
proof_of_creation (4),
proof_of_sender (5),
proof_of_origin (6)
} OPTIONAL,
o evidence_type_oid OBJECT IDENTIFIER OPTIONAL,
-- may be used in place of above parameter if OID is known
o evidence_validity_duration INTEGER,
-- duration_in_minutes
-- DURATION_HOUR = 60;
-- DURATION_DAY = 1440;
-- DURATION_WEEK = 10080;
-- DURATION_MONTH = 43200;// 30 days
-- DURATION_YEAR = 525600;//365 days
o mech_indep_encap_req BOOLEAN -- (see Appendix A)
o Originator_Information PARAMETER BUNDLE
o token_generator_name INTERNAL NAME,
-- obtained from the credentials of the originator
-- (e.g., from its public key certificate)
o token_generator_role Originator_Role OPTIONAL,
-- (see Section 2.3.4.1)
o protection_time INTEGER OPTIONAL
o Bad_Target_Name PARAMETER BUNDLE -- (see Section 2.3.2.2)
o bad_targ_name INTERNAL NAME,
o bad_targ_status INTEGER
-- a status flag giving the reason for rejection of the
-- name in bad_targ_name
o Target_Info PARAMETER BUNDLE -- same as in Section 2.3.2.2
o targ_names SET OF INTERNAL NAME,
o bad_targ_count INTEGER,
o bad_target_names SET OF Bad_Target_Name
o Request_Features PARAMETER BUNDLE
o requested_evidence_type INTEGER {
no_evidence (0), - used when no token desired
proof_of_receipt (1),
proof_of_delivery (2),
proof_of_approval (3), },
o nr_req_policy OBJECT IDENTIFIER,
o evidence_from Target_Info,
o evidence_to Target_Info,
o include_received_token_in_evidence BOOLEAN
The following data_type is used in the "EV" protection calls.
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o Nr_Operation INTEGER {
evidence_and_or_evidence_request (1),
returned_evidence (2) }
2.3.3.3. IDUP_EV major_status codes
The following major_status return codes are defined for the "EV"
calls in this section:
o GSS_S_COMPLETE
-- indicates that the evidence is complete
o IDUP_S_INCOMPLETE
o IDUP_S_MORE_OUTBUFFER_NEEDED
-- returned (by any EV call) to indicate that there is more output
-- data than can fit into the supplied buffers. The application
-- should save the returned data and call again to retrieve the
-- remaining output.
o IDUP_S_INCONSISTENT_PARAMS
o GSS_S_CREDENTIALS_EXPIRED
o IDUP_S_NO_MATCH
o IDUP_S_NO_ENV
o GSS_S_FAILURE
If Target_Info is used as an input parameter (i.e., if an evidence is
being requested ), the following major_status return code is also
defined:
o IDUP_S_BAD_TARG_INFO
Note for this return code that if one or more of the targets in
targ_names cannot be used as a valid recipient of the P-IDU, these
names will be returned in bad_targ_names (with associated status
codes in bad_targ_status). As long as at least one of the targets
can be used, however, this does not cause this call to fail (i.e.,
the failure code IDUP_S_BAD_TARG_INFO is not returned); it is the
caller's choice to discontinue IDU protection if the target set which
can be used is unsuitable for the caller's purposes.
2.3.3.4. IDUP_EV_SingleBuffer_Generate call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o nr_operation Nr_Operation,
o Nr_Options PARAMETER BUNDLE,
o idu_buffer OCTET STRING,
o form_complete_pidu BOOLEAN,
-- if TRUE the implementation will attempt to form a complete PIDU
o include_data_in_token BOOLEAN,
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-- if TRUE, data provided in idu_buffer will be included in the
-- generated token; if FALSE, the data will not be included
o Request_Features PARAMETER BUNDLE
-- the type of the evidence that is requested;
-- policy under which the returned evidence should be generated;
-- the recipients that are supposed to send back an evidence;
-- the recipients that should receive the requested evidence;
-- an indicator include_received_token_in_evidence:
-- if TRUE, the evidence token incorporating the request will be
-- included in the data for which recipients will generate
-- evidence; if FALSE, evidence will be generated using only
-- the data (and not the token incorporating the request).
o additional_protection BOOLEAN -- (see Section 2.3.2.4)
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o token OCTET STRING,
o evidence_check OCTET STRING,
-- present only if an evidence is requested. Consists of data to
-- be used to verify the requested token(s) (if any) when they are
-- received.
Description:
This operation generates a non-repudiation token associated with the
data passed in an input buffer. Two kinds of operations can be
performed (using the Nr_Operation parameter):
a) generating a token that includes either an evidence only, or
an evidence request only, or both an evidence and an evidence
request;
b) generating a response token for some recipients that includes an
evidence generated as a response to a request (in this case the
idu_buffer is used to enter the request token that was received).
It is possible to request the generation of complete evidence. This
may succeed or fail; if it fails, a subsequent call to
Form_Complete_PIDU can be made.
2.3.3.5. IDUP_EV_SingleBuffer_Verify call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o token OCTET STRING,
o external_idu_buffer OCTET STRING,
-- if not present within the token
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o evidence_check OCTET STRING,
-- present only if the input token is a response to a previous
-- request for evidence (this parameter is used to validate that
-- evidence).
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o Nr_Options PARAMETER BUNDLE,
o Originator_Information PARAMETER BUNDLE,
o Request_Features PARAMETER BUNDLE,
o trusted_time_stamping_time INTEGER OPTIONAL,
-- present for informational purposes only
o complete_evidence_before INTEGER OPTIONAL,
-- if the major status code that is returned is
-- IDUP_S_INCOMPLETE, IDUP_Form_Complete_PIDU should be called
-- with the same token before this time.
-- This may be required, for example, in order to insure that
-- the time skew between the evidence generation time and
-- the trusted time service's countersignature on the evidence
-- falls within the interval allowed by the current NR policy.
o complete_evidence_after INTEGER OPTIONAL,
-- if the major status code that is returned is
-- IDUP_S_INCOMPLETE, IDUP_Form_Complete_PIDU should be called
-- with the same token after this time.
-- This may be required, for example, to insure that all
-- authorities involved in generating the evidence have passed
-- the last time at which the current NR policy allows them to
-- repudiate their keys.
o encapsulated_idu_buffer OCTET STRING
-- if the IDU was present within the token
o additional_unprotection BOOLEAN -- (see Section 2.3.2.5)
Description:
Verifies the validity and discloses the content of a nr_token.
If the token containing the evidence to be verified was provided to
the calling application by a partner responding to the calling
application's request, then the calling application must pass the
evidence check it received when it generated the request as a
parameter along with the token it received from the partner.
Output indicators are provided which give guidance about the time or
times at which form_complete_pidu should be called; see the parameter
descriptions for explanations of these indicators and their use. Note
that the time specified by complete_evidence_before may be earlier
than that specified by complete_evidence_after; in this case it will
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be necessary to call form_complete_pidu twice.
Because keys can be revoked or declared compromised, the return from
verify_evidence cannot in all cases be a definitive "valid" or
"invalid"; sometimes "conditionally valid" may be returned, depending
upon the policy in use. IDUP_S_INCOMPLETE will be returned, for
example, if:
- the interval during which the generator of the evidence may
permissibly declare his key invalid has not yet expired (and
therefore it is possible that the evidence may be declared invalid
in the future), or
- trusted time is required for verification, and the time obtained
from the token is not trusted.
2.3.3.6. IDUP_EV_MultiBuffer_StartGenerate call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o nr_operation Nr_Operation,
o Nr_Options PARAMETER BUNDLE,
o form_complete_pidu BOOLEAN,
o include_data_in_token BOOLEAN,
o idu_size INTEGER, -- (see Section 2.3.4.2)
o Request_Features PARAMETER BUNDLE
o additional_protection BOOLEAN -- (see Section 2.3.2.4)
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o initial_pidu_buffer OCTET STRING
-- may be empty (depends on underlying mechanism)
Description:
Using the security environment referenced by env_handle, initialize
the data structures required to begin the generation of a token. The
IDU will be supplied in multiple buffers to the
IDUP_EV_Process_Buffer call). Two kinds of operations can be
performed (using the Nr_Operation parameter) :
a) generating a token that includes either an evidence only, or
an evidence request only, or both an evidence and an evidence
request.
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b) generating a return token for some recipients that includes an
evidence generated as a response to a request. In that case the
received token will be passed into the subsequent
IDUP_EV_Process_Buffer calls. The boolean include_data_in_token
is ignored as the output will always be contained in a single
token. The Request_Features are ignored in that case at this
time in order to keep things simple and to avoid the piggy-
backing that is theoretically possible.
It is possible to request the generation of complete evidence. This
may succeed or fail; if it fails, a subsequent call to
Form_Complete_PIDU can be made.
2.3.3.7. IDUP_EV_MultiBuffer_EndGenerate call
Inputs:
o env_handle ENVIRONMENT HANDLE
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o final_pidu OCTET STRING,
o token OCTET STRING,
o evidence_check OCTET STRING
-- present only if an evidence is requested.
Description:
Using the security environment referenced by env_handle, provide the
requested token or the final P-IDU. A token will be generated if
encapsulation was not requested; otherwise, the final P-IDU is
provided.
2.3.3.8. IDUP_EV_MultiBuffer_StartVerify call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o token OCTET STRING,
o evidence_check OCTET STRING,
-- present only if an evidence has been previously requested.
Outputs:
o major_status INTEGER,
o minor_status INTEGER
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Description:
Using the security environment referenced by env_handle, initialize
the data structures required to begin the process of verifying the
token. The P-IDU will be supplied in multiple buffers to the
IDUP_EV_Process_Buffer call.
2.3.3.9. IDUP_EV_MultiBuffer_EndVerify call
Input:
o env_handle ENVIRONMENT HANDLE
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o Nr_Options PARAMETER BUNDLE,
o Originator_Information PARAMETER BUNDLE,
o Request_Features PARAMETER BUNDLE,
o trusted_time_stamping_time INTEGER OPTIONAL,
o complete_evidence_before INTEGER OPTIONAL,
o complete_evidence_after INTEGER OPTIONAL,
o idu_buffer OCTET STRING
-- if the IDU was present within the token
o additional_unprotection BOOLEAN -- (see Section 2.3.2.5)
Description:
Using the security environment referenced by env_handle, complete the
verification processing on the data and provide verified output
parameters to the caller when the major status code is either:
o GSS_S_COMPLETE or
o IDUP_S_INCOMPLETE
2.3.3.10. IDUP_EV_Process_Buffer call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o input_buffer OCTET STRING
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o output_buffer OCTET STRING
-- may be zero length (depends on underlying mechanism and
-- corresponding Generate () call and options
-- (e.g., data_included_in_token)
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Description:
Using the security environment referenced by env_handle, continue the
processing on the data in input_buffer and, if it is available, put
any resulting output data in output_buffer. The application calls
this routine over and over again with new buffers of data until it
has processed all the data buffers of the IDU/PIDU. It then calls the
appropriate End() call to complete the processing.
2.3.4. The "GP" Calls
The "GP" group of calls provides a powerful interface to flexible and
sophisticated combinations of protection and unprotection services.
This power and flexibility, however, necessitates a more complex
interface than either the SE or the EV calls. Furthermore, such
combinations of services are not needed in many of the security
mechanisms in common use today (although this is likely to change as
time goes on). The GP calls are therefore specified to be OPTIONAL
and need not be supported by IDUP-conformant implementations. Note,
however, that the structure of IDUP tokens should be such that the
SE/EV and GP calls may be used interchangably by the receiver.
2.3.4.1. Parameter Bundles
The concept of "parameter bundles" is used in the calls presented in
the following subsections in order to simplify their presentation and
clarify their intended purpose and use (note that specific language
bindings may or may not use parameter bundles for its actual calling
conventions). A parameter bundle is simply a set of closely-related
parameters of a call which are either all used by / available to the
calling application or all not used by / unavailable to the calling
application. These parameters may be all input parameters, all
output parameters, or any combination of the two.
An example use envisioned for parameter bundles in a language such as
C would be as a structure, where individual parameters in the bundle
are structure members. The calling application wishing to use a
particular bundle would then allocate the appropriate structure
variable, assign the desired input values to the appropriate members,
and pass the address of the structure as the bundle "parameter". On
output, the values of the appropriate output members may be read. An
application not wishing to use a particular bundle (or one which is
satisfied with default values for all input parameters of the bundle
and which doesn't care about output values), can pass NULL as the
bundle "parameter". From the mechanism implementor's perspective, if
a parameter bundle is not supported (for example, if it represents a
security service which is not supported by the implementation), then
any non-NULL value passed as the bundle parameter will generate an
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error status return code.
[Note that the parameter bundles given below, except where explicitly
referenced by the SE and EV calls, are specific to the (optional) GP
calls. Thus, these bundles need not be supported by IDUP-conformant
implementations if the GP calls are not supported.]
The following parameter bundles are used in the subsequent protection
and unprotection sets of calls. A parameter preceded by "(I)" is an
input parameter; one preceded by "(O)" is an output parameter; one
preceded by neither is an input if the bundle itself is an input and
is an output if the bundle itself is an output; one preceded by "(X)"
is the opposite: an output if the bundle itself is an input and an
input if the bundle itself is an output.
o Mech_Specific_Info PARAMETER BUNDLE
-- actual parameters included in this bundle are defined by (and
-- specific to) the underlying mechanism
o Sensitivity PARAMETER BUNDLE,
-- actual parameters included in this bundle are defined by (and
-- specific to) the underlying mechanism, but may include
-- codified values for "Unclassified", "Secret", "Top Secret",
-- and so on
o Service_Creation_Info PARAMETER BUNDLE
-- actual parameters included in this bundle are defined by (and
-- specific to) the underlying mechanism, but it is mandatory
-- that they include at least service_id and Quality
o Service_Verification_Info PARAMETER BUNDLE
-- actual parameters included in this bundle are defined by (and
-- specific to) the underlying mechanism, but it is mandatory
-- that they include at least service_id and Quality
o Quality PARAMETER BUNDLE
o qop_algs UNSIGNED INTEGER,
o qop_algID AlgorithmIdentifier, --overrides qop_algs
o validity UNSIGNED INTEGER,
-- protection guaranteed to be valid until time specified
o policy_id OBJECT IDENTIFIER,
-- security policy under which protection is/was carried out
o allow_policy_mapping BOOLEAN,
-- determines whether mapping between policy IDs is allowed
o actual_policy_time INTEGER
-- time at which the above policy rules came into effect
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o Idu_Information PARAMETER BUNDLE,
o idu_type_oid OBJECT IDENTIFIER,
o idu_type_string OCTET STRING,
o idu_title OCTET STRING,
o idu_sensitivity Sensitivity,
o pidu_type_oid OBJECT IDENTIFIER,
o pidu_type_string OCTET STRING,
o pidu_title OCTET STRING,
o pidu_sensitivity Sensitivity,
o Prot_Information PARAMETER BUNDLE,
o originator_name INTERNAL NAME,
o originator_role Originator_Role,
o idu_information Idu_Information,
o protection_time INTEGER,
o Originator_Role PARAMETER BUNDLE, -- role in organization
o domain_name INTERNAL NAME OPTIONAL,
o role PRINTABLE STRING,
o role_info_is_authenticated BOOLEAN
-- TRUE if info. is authenticated (e.g., inside a cert.)
o Special_Conditions PARAMETER BUNDLE,
o prot_oper_id INTEGER,
o form_complete_pidu BOOLEAN,
-- input to protection operations for evidence generation
o pidu_in_solic_service BOOLEAN,
-- in protection operations, used as input for service
-- solicitation to request that receiver include the
-- received PIDU when generating the response. In unprot.
-- operations, used as output to inform receiver that PIDU
-- should be included when generating the response.
o use_trusted_time BOOLEAN,
o use_untrusted_time BOOLEAN,
o mech_indep_encap_req BOOLEAN -- (see Appendix A)
o Bad_Target_Name PARAMETER BUNDLE,
o (O) bad_targ_name INTERNAL NAME,
o (O) bad_targ_status INTEGER,
-- a status flag giving the reason for rejection of
-- the name in bad_targ_name. Specified reasons include:
-- SYNTAX_INVALID (0)
-- the syntax of the name is invalid;
-- NAME_UNRECOGNIZED (1)
-- the name is not recognized;
-- NAME_AMBIGUOUS (2)
-- the name cannot be resolved;
-- ACCESS_DENIED (3)
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-- access to this target is denied;
-- CERTIFICATE_NOT_FOUND (4)
-- the encryption certificate of the target could
-- not be found.
o Target_Info PARAMETER BUNDLE,
o targ_names SET OF INTERNAL NAME,
o (O) bad_targ_count INTEGER,
o (O) bad_target_names SET OF Bad_Target_Name,
o General_Service_Data PARAMETER BUNDLE,
o target_info Target_Info,
o (X) unencapsulated_token OCTET STRING,
-- zero length if encapsulation_request is TRUE
o (O) minor_status INTEGER,
Three types of protection services are defined in IDUP. These are:
1. perform unsolicited service (i.e., act on a locally-generated
service request),
2. perform solicited service (i.e., act on a remotely-generated
service request), and
3. perform service solicitation (i.e., send a service request to
the remote end).
As an originator, applying data confidentiality with data integrity,
or data origin authentication with data integrity, or proof of origin
evidence is an example of service type 1. As a target, creating a
proof of delivery (i.e., receipt) evidence token as the result of a
request received from the originator is an example of service type 2.
Finally, as an originator, submitting a request that one or more
targets return a receipt for the data sent is an example of service
type 3.
The first four parameters in the Prot_Service parameter bundle
pertain to all service types; the fifth parameter is used if and only
if service type 2 is desired; parameters 6-8 are used if and only if
service type 3 is desired.
o Prot_Service PARAMETER BUNDLE
o (I) prot_service_type INTEGER,
o (I) service_id OBJECT IDENTIFIER,
o (I) quality Quality, -- NULL specifies default Quality
o (I) general_service_data General_Service_Data,
o (I) service_creation_info Service_Creation_Info,
o (I) service_to SET OF INTERNAL NAME,
o (O) service_verification_info Service_Verification_Info,
o (O) service_verification_info_id INTEGER,
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Also, three types of unprotection services are defined. These are:
1. receive unsolicited service (i.e., process unrequested
remotely-generated service),
2. receive solicited service (i.e., process remotely-generated
response to locally-generated request), and
3. receive service solicitation (i.e., process req. from rem. end)
As a target, unprotecting an encrypted message, or verifying the
originator's proof of origin is an example of service type 1. As an
originator, verifying a proof of delivery which you requested from a
target is an example of service type 2. Finally, as a target,
receiving a request from an originator for a proof of delivery is an
example of service type 3.
The first four parameters in the Unprot_Service parameter bundle
pertain to all service types; parameters 5-6 are used if and only if
service type 2 is required; parameters 7-8 are used only if service
type 3 is required.
o Unprot_Service PARAMETER BUNDLE
o (O) unprot_service_type INTEGER,
o (O) service_id OBJECT IDENTIFIER,
o (O) quality Quality,
-- actual Quality specified (never NULL)
o (O) general_service_data General_Service_Data,
o (O) service_verification_info_id INTEGER,
o (I) service_verification_info Service_Verification_Info,
o (O) service_to SET OF INTERNAL NAME,
o (O) service_creation_info Service_Creation_Info,
2.3.4.2. IDUP_Start_Protect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o Mech_Specific_Info PARAMETER BUNDLE,
-- NULL selects the mechanism-defined default values
o Idu_Information PARAMETER BUNDLE,
o Special_Conditions PARAMETER BUNDLE,
o encapsulation_request BOOLEAN,
o single_idu_buffer OCTET STRING,
-- non-zero length for this buffer means that Protect/End_Protect
-- won't be called (i.e., entire IDU is contained in this buffer)
o idu_size INTEGER,
-- size (in bytes) of the IDU to be protected;
-- may be "-1" signifying "UNKNOWN" (note that some mechanisms
-- may not support encapsulation in such a case)
o Target_Info PARAMETER BUNDLE,
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o Services_to_Perform SET OF Prot_Service,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o midu_buffer OCTET STRING,
-- zero length if encapsulation_request is TRUE;
-- may be zero length otherwise (depends on underlying mechanism)
o pidu_buffer OCTET STRING,
-- zero length if encapsulation_request is FALSE;
-- may be zero length otherwise (depends on underlying mechanism)
Return major_status codes:
o GSS_S_COMPLETE
-- the protection process can begin (or has completed, if
-- single_idu_buffer has non-zero length).
o IDUP_S_MORE_OUTBUFFER_NEEDED
o GSS_S_CREDENTIALS_EXPIRED
o IDUP_S_NO_ENV
o IDUP_S_ENCAPSULATION_UNAVAIL
o IDUP_S_SERVICE_UNAVAIL
o IDUP_S_REQ_TIME_SERVICE_UNAVAIL
o IDUP_S_UNKNOWN_OPER_ID
o GSS_S_BAD_QOP
o IDUP_S_BAD_TARG_INFO
o GSS_S_FAILURE
Using the security environment referenced by env_handle, initialize
the data structures required to begin the process of protecting the
IDU buffers. The caller requests specific protection services by
supplying the appropriate Prot_Service parameter bundles in
Services_to_Perform. Each service is able to return a minor status
code to the calling application, if necessary.
The calling application, knowing the size of the IDU it wishes to
protect and the buffer size which it has available to it, can choose
to input the entire IDU in a single buffer and omit the subsequent
IDUP_Protect() and IDUP_End_Protect() calls. Furthermore, the
application can request that the resulting M-IDU be encapsulated in
the token -- so that the token contains the entire P-IDU -- rather
than having it be returned separately in midu_buffer. Encapsulation,
however, may not be supported by all underlying mechanisms or
implementations; if this is the case, the
IDUP_S_ENCAPSULATION_UNAVAIL major status code will be returned and
M-IDU will be returned in midu_buffer.
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For those mechanisms which allow or require multiple stages of
processing, each producing a different aspect of protection for the
IDU, the operation identifier prot_oper_id is used to specify which
stage is currently being requested by the application. An example
where this would be useful is a mechanism which implements the signed
Message Security Protocol [MSP]. As another example, a mechanism may
choose to do a digital signature in two stages: one for the hashing
of the message and another for the signature on the hash. The
calling application would therefore use the protection set of calls
on the IDU in stage 1 and then use the protection set of calls on the
token (from stage 1) in stage 2.
Note that prot_oper_id is simply an integer (1, 2, 3, ..., n, where
"n" is the number of stages as defined by the mechanism (typically 1
or 2)). The calling application uses this parameter to indicate to
the underlying mechanism whether it wishes to do stage 1 of
protection / unprotection processing, or stage 2, and so on. Portable
applications may pass "0" to let the mechanism choose the stage (note
that mechanism implementers may still iterate when prot_oper_id = 0
(e.g., use output as next input, et cetera).
If one or more of the targets in targ_names cannot be used as a valid
recipient of the P-IDU, these names will be returned in
bad_targ_names (with associated status codes in bad_targ_status). As
long as at least one of the targets can be used, this does not cause
this call to fail; it is the caller's choice to discontinue IDU
protection if the target set which can be used is unsuitable for the
caller's purposes. Note that each Prot_Service parameter bundle can
also input a list of targ_names; this is used if a separate list is
to be used for that service only (the general list of targets is to
be used for all services unless overridden in this way).
2.3.4.3. IDUP_Protect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o input_buffer OCTET STRING,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o output_buffer OCTET STRING
-- may be zero length if encapsulation_request was set to TRUE in
-- IDUP_Start_Protect() (depends on underlying mechanism)
Return major_status codes:
o GSS_S_COMPLETE
o IDUP_S_NO_ENV
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o GSS_S_FAILURE
Using the security environment referenced by env_handle, continue the
protection processing on the data in input_buffer and, if the
underlying mechanism defines this, put any resulting P-IDU/M-IDU data
in output_buffer. The application calls this routine over and over
again with new buffers of data until it has protected all the data
buffers of the IDU. It then calls IDUP_End_Protect() to complete the
protection processing.
2.3.4.4. IDUP_End_Protect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o Services_to_Perform SET OF Prot_Service,
o final_midu_buffer OCTET STRING,
-- zero length if encapsulation_request was set to TRUE in
-- IDUP_Start_Protect(), in which case pidu is used
o final_pidu_buffer OCTET STRING,
-- zero length if encapsulation_request was set to FALSE in
-- IDUP_Start_Protect(), in which case token and midu are used
Return major_status codes:
o GSS_S_COMPLETE
-- protection has successfully completed and the resulting P-IDU
-- is ready for transfer. If defined by the underlying mechanism,
-- final_midu_buffer will contain any residual M-IDU data.
o IDUP_S_MORE_OUTBUFFER_NEEDED
o IDUP_S_NO_ENV
o GSS_S_FAILURE
Using the security environment referenced by env_handle, complete the
protection processing on the data and place the computed output in
final_pidu_buffer (or final_midu_buffer and the unencapsulated_token
parameter for each Prot_Service). If a service was requested from
one or more targets in Start_Protect() - and if this is supported by
the underlying mechanism - Service_Verification_Info will hold
whatever data is necessary for the mechanism to verify a service
returned by a target (unprotector) of the P-IDU. Successful
application of IDUP_End_Protect() does not guarantee that the
corresponding unprotection set of calls can necessarily be performed
successfully when the P-IDU arrives at the target (for example, it
may be damaged in transit).
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2.3.4.5. IDUP_Start_Unprotect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o Mech_Specific_Info PARAMETER BUNDLE,
-- NULL selects the mechanism-defined default values
o single_pidu_buffer OCTET STRING,
-- non-zero length for this buffer means that IDUP_Unprotect() and
-- IDUP_End_Unprotect() will not be called (i.e., the entire P-IDU
-- (if encapsulation is used) or M-IDU (if encap. is not used)
-- is contained in this buffer)
o partial_pidu_buffer OCTET STRING,
-- may be an arbitrary-sized piece of the full pidu (if the
-- application's buffer isn't large enough to hold entire pidu).
-- Used if pidu_buffer will be input a buffer at a time (except
-- that the final buffer must be passed in final_pidu_buffer
-- rather than partial_pidu_buffer). Only one of
-- single_pidu_buffer and partial(final)_pidu_buffer can have
-- nonzero length.
o final_pidu_buffer OCTET STRING,
o Special_Conditions PARAMETER BUNDLE,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o Services_to_Receive SET OF Unprot_Service,
o Prot_Information PARAMETER BUNDLE,
o single_idu_buffer OCTET STRING,
-- if this buffer has non-zero length, then service processing has
-- been completed on the data in single_pidu_buffer
o initial_idu_buffer OCTET STRING,
-- holds any data from partial(final)_pidu_buffer which has been
-- unprotected; remaining data will be returned by Unprotect and
-- End_Unprotect as they are called with successive buffers of
-- pidu
o Service_Verification_Info PARAMETER BUNDLE,
-- used only if target is on "service_to" list in Unprot_Service
o service_verification_info_id INTEGER,
-- used only if target is on "service_to" list in Unprot_Service
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Return major_status codes:
o GSS_S_COMPLETE
-- unprotection processing can begin (or has completed, if
-- single_idu_buffer has non-zero length).
o IDUP_S_INCOMPLETE
-- used only if single_idu_buffer has non-zero length.
o IDUP_S_MORE_OUTBUFFER_NEEDED
o IDUP_S_MORE_PIDU_NEEDED
o GSS_S_DEFECTIVE_TOKEN
o IDUP_S_INAPPROPRIATE_CRED
o IDUP_S_INCONSISTENT_PARAMS
o IDUP_S_DEFECTIVE_VERIF
o IDUP_S_NO_MATCH
o IDUP_S_SERVICE_UNAVAIL
o IDUP_S_REQ_TIME_SERVICE_UNAVAIL
o IDUP_S_SERV_VERIF_INFO_NEEDED
o GSS_S_CREDENTIALS_EXPIRED
o IDUP_S_NO_ENV
o IDUP_S_UNKNOWN_OPER_ID
o GSS_S_BAD_QOP
-- the qop_algs value specified in P-IDU for at least one of the
-- services is unavailable in the local mechanism, so processing
-- cannot continue.
o GSS_S_BAD_MIC
o IDUP_S_BAD_DOA_KEY
o IDUP_S_BAD_KE_KEY
o IDUP_S_BAD_ENC_IDU
o GSS_S_FAILURE
Using the security environment referenced by env_handle, initialize
the data structures required to begin the process of unprotecting a
P-IDU. The caller will be alerted as to which services were applied
to the P-IDU in the returned Services_to_Receive set of parameters.
If encapsulation was not used by the originator, it is the receiving
application's responsibility to separate the received P-IDU into a
M-IDU and one or more unencapsulated_token buffers (the latter being
input in separate Unprot_Service bundles in the Services_to_Receive
parameter). These unencapsulated_token buffers should be input
before the M-IDU (i.e., in IDUP_Start_Unprotect) or after the M-IDU
(i.e., in IDUP_End_Unprotect) as appropriate; this order may be
dictated, for example, by their placement in the in-coming message.
If unprotection will be applied more than once to a given P-IDU, it
is the responsibility of the calling application to remember if a
service solicitation has been responded to previously (i.e., if the
requested service has already been generated / sent for that P-IDU)
and thus ignore subsequent solicitations on unprotect.
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The time flags indicate whether to consult trusted, untrusted, or no
time (if both flags are FALSE) during the unprotection operation. If
the current time is not to be checked, then unprotection may be
successful even if the protector's key has expired since the P-IDU
was generated (that is, if the Validity period -- as specified in the
Quality parameter bundle -- has expired).
If the underlying mechanism supports it and if this information is
contained in the P-IDU, information regarding the originator (that
is, the entity which used the protection set of calls to generate
this P-IDU) is returned in the Prot_Information parameter bundle.
2.3.4.6. IDUP_Unprotect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o input_buffer OCTET STRING
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o output_buffer OCTET STRING
Return major_status codes:
o GSS_S_COMPLETE
o IDUP_S_NO_ENV
o GSS_S_FAILURE
Using the security environment referenced by env_handle, continue the
unprotection processing on the data in input_buffer, putting any
resulting IDU data in output_buffer (if required).
2.3.4.7. IDUP_End_Unprotect call
Inputs:
o env_handle ENVIRONMENT HANDLE,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o Prot_Information PARAMETER BUNDLE,
o Services_to_Receive SET OF Unprot_Service,
o final_idu_buffer OCTET STRING,
o Service_Verification_Info PARAMETER BUNDLE,
-- used only if target is on "service_to" list in Unprot_Service
o service_verification_info_id INTEGER,
-- used only if target is on "service_to" list in Unprot_Service
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Return major_status codes:
o GSS_S_COMPLETE
-- residual IDU data will be returned in final_idu_buffer.
o IDUP_S_INCOMPLETE
o IDUP_S_MORE_OUTBUFFER_NEEDED
o GSS_S_BAD_MIC
o IDUP_S_BAD_DOA_KEY
o IDUP_S_BAD_KE_KEY
o IDUP_S_BAD_ENC_IDU
o IDUP_S_NO_ENV
o GSS_S_FAILURE
Using the security environment referenced by env_handle, complete the
unprotection processing on the data and return the appropriate status
code. If there is any residual IDU data it will be returned in
final_idu_buffer.
If the IDUP_S_INCOMPLETE major status value is returned, all output
parameters are conditionally valid; the unprotection set of functions
will have to be called again (perhaps with a complete P-IDU, as
produced by IDUP_Form_Complete_PIDU) in order to get valid values for
all parameters. "Conditional validity" may arise, for example, if
all relevant certificates verify correctly, but it is not yet past
the time up to which the current policy allows the authorities
involved to repudiate their keys.
If the underlying mechanism supports it and if this information is
contained in the token, information regarding the originator (that
is, the entity which used the protection set of calls to generate
this token) is returned in the Prot_Information parameter bundle.
This information may or may not be omitted if it was returned by the
IDUP_Start_Unprotect() call.
Note that, unlike GSS-API, IDUP-GSS-API does not incorporate the
concept of error tokens transferred between sender and recipient
since the protection and unprotection of an IDU may be separated by
an indefinite amount of time and may or may not be performed by the
same entity.
2.4. Special-Purpose Calls
2.4.1. Relationship to GSS-API
The special-purpose call described in this section has no analog in
GSS-API RFC-2078">[RFC-2078]. This call is used to complete a P-IDU (that is,
to generate a P-IDU which can be unprotected successfully with no
additional data at any time during its validity period). This call
may not be supported by all underlying IDUP mechanisms or
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implementations.
2.4.2. IDUP_Form_Complete_PIDU call
Inputs:
o env_handle ENVIRONMENT HANDLE,
o single_pidu_buffer OCTET STRING,
o partial_pidu_buffer OCTET STRING,
-- an arbitrary-sized piece of the full pidu token. Used if pidu
-- will be input a buffer at a time (except that the final buffer
-- must be passed in final_pidu_buffer rather than
-- partial_pidu_buffer). Only one of single_pidu_buffer and
-- partial(final)_pidu_buffer can have nonzero length.
o final_pidu_buffer OCTET STRING,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o pidu_token_out OCTET STRING -- the augmented PIDU; may be complete
o call_again_before INTEGER,
o call_again_after INTEGER,
o trusted_time_stamping_time INTEGER -- for information only
Return major_status codes:
o GSS_S_COMPLETE
o IDUP_S_MORE_OUTBUFFER_NEEDED
o IDUP_S_INCOMPLETE
-- generation of the P-IDU is not yet complete. The application
-- should call this function again before the time given in
-- call_again_before (if not NULL), or after the time given in
-- call_again_after (if not NULL), or both (if neither are NULL).
o IDUP_S_INCONSISTENT_PARAMS
o IDUP_S_SERVICE_UNAVAIL
o GSS_S_DEFECTIVE_TOKEN
o GSS_S_FAILURE
Form_Complete_PIDU is used primarily by the evidence services; in
particular, when the evidence token itself does not contain all the
data required for its verification and it is anticipated that some of
the data not stored in the token may become unavailable during the
interval between generation of the evidence token and verification
unless it is stored in the token. The Form_Complete_PIDU operation
gathers the missing information and includes it in the token so that
verification can be guaranteed to be possible at any future time.
This call generates a PIDU which can be unprotected successfully with
no additional data at any time during its validity period. [For
background information on the notion of "complete" evidence, see
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"CORBA Security Service v1.2 Draft D02", 18 June 1997.]
Using the security environment referenced by env_handle, complete the
generation of a P-IDU token and return the appropriate status value
along with the completed token (if available). Such a call may be
used, for example, for the purpose of batch evidence generation on an
"evidence server". A local machine may be able to use the protection
set of calls to fill out most of an evidence token and then send a
number of these to a batch processor which forms the complete
evidence tokens (perhaps by adding a certification path, or a
timestamp and signature from a timestamping authority). As another
example, on the receiving end an application may make such a call in
order to collect all the information necessary to unprotect a P-IDU
(such as all relevant certificates and Certificate Revocation Lists);
this will ensure that the calls to the unprotection set of operations
will be entirely local (i.e., can be performed off-line) and fast.
Note that the complete P-IDU generated will be formed using trusted
time if this is available in the environment referenced by env_handle
and will use untrusted time or no time otherwise (depending on what
is available).
2.5. Support calls
2.5.1. Relationship to GSS-API
Support calls in IDUP-GSS-API are to be understood and used as
described in GSS-API RFC-2078">[RFC-2078]. The calls described in Section 2.4
of GSS-API (including all associated parameters) are unchanged. The
following additional calls are specified for IDUP-GSS-API.
2.5.2: IDUP_Acquire_cred_with_auth call
Inputs:
o desired_name INTERNAL NAME,
-- NULL requests locally-determined default
o authenticator OCTET STRING
-- string which authenticates the caller claiming to be
-- desired_name
o lifetime_req INTEGER,
-- in seconds; 0 requests default
o desired_mechs SET OF OBJECT IDENTIFIER,
-- empty set requests system-selected default
o cred_usage BIT STRING
-- actual values which can be used currently correspond to those
-- given in Section 2.1.1 (i.e.,
-- ENCRYPT_ONLY 8
-- DECRYPT_ONLY 16
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-- SIGN_ONLY 32
-- VERIFY_ONLY 64
-- with the values logically OR'ed together in any desired
-- combination to restrict credential usage; OR'ing all values
-- results in NO_RESTRICTION).
-- Future possible values for this parameter are for further
-- study (note that the type of this parameter is BIT STRING
-- (rather than INTEGER as in GSS_Acquire_cred) to facilitate
-- such future expansion).
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o output_cred_handle CREDENTIAL HANDLE,
o actual_mechs SET OF OBJECT IDENTIFIER,
o actual_cred_usage BIT STRING,
o lifetime_rec INTEGER
-- in seconds, or reserved value for INDEFINITE
This call (which need not be supported by all underlying mechanisms
or implementations) is identical to the GSS_Acquire_cred call, with
the exception of the added input parameter "authenticator" and the
added output parameter "actual_cred_usage". The authenticator
(typically a password, pass-phrase, or PIN) is used to authenticate
the caller claiming to be desired_name to the underlying GSS (or
mechanism) code. The actual_cred_usage specifies the actual uses
available for these credentials; it is up to the caller to determine
if this is sufficient for its purposes.
Implementations that are able to authenticate the caller in some
other way are encouraged to use the GSS_Acquire_cred call; those
having no other means available to them, or wishing to explicitly
authenticate the caller at the time of credential acquisition, should
use the IDUP_Acquire_cred_with_auth call (if supported).
Note that the return major status codes for this call are identical
to those given for the GSS_Acquire_cred call. If the authentication
fails (e.g., the wrong authenticator is supplied for the given
desired_name), the major status GSS_S_FAILURE is returned (along with
an appropriate minor status code).
2.5.3. IDUP_Get_token_details call
Inputs:
o token OCTET STRING,
-- all the data to be returned shall be within the first 4 KB of
-- the token; hence, a single call is needed. It is not necessary
-- to provide the entire token when the token includes the IDU.
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o mech_type SET OF OBJECT IDENTIFIER
-- input if known (typically SET will contain a single member)
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o actual_mech_type OBJECT IDENTIFIER,
o data_included_in_token BOOLEAN,
-- true if the data is encapsulated
o idu_size INTEGER,
o has_SE_protection BOOLEAN,
o has_EV_protection BOOLEAN,
o PIDU_Information PARAMETER BUNDLE,
o nr_policy OBJECT IDENTIFIER,
-- this and subsequent parameters pertain only to evidence tokens
o Nr_Options PARAMETER BUNDLE,
o Originator_Information PARAMETER BUNDLE,
o time_stamping_time INTEGER OPTIONAL
o Request_Features PARAMETER BUNDLE,
-- describes the included request, if any.
o requested_evidence_back BOOLEAN,
-- true if this is an evidence generated in response to a
-- previously-sent request
o evidence_check OCTET STRING,
-- meaningful if the boolean above is true
Return major_status codes:
o GSS_S_COMPLETE
-- input_token could be parsed for all relevant fields.
o GSS_S_CREDENTIALS_EXPIRED
o GSS_S_DEFECTIVE_TOKEN
-- the mechanism type could be parsed, but either the other fields
-- could not be determined from the input_token, or their values
-- did not correspond to valid values for that mechanism.
o GSS_S_FAILURE
-- the mechanism type was missing or corrupted.
IDUP_Get_token_details() is used to return to an application the
attributes that correspond to a given input token. Since IDUP-GSS-
API tokens are meant to be opaque to the calling application, this
function allows the application to determine information about the
token without having to violate the opaqueness intention of IDUP. Of
primary importance is the mechanism type, which the application can
then use as input to the IDUP_Establish_Env() call in order to
establish the correct environment in which to have the token
processed.
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If all tokens are framed as suggested in Section 3.1 of RFC-2078">[RFC-2078]
(mandated in the Kerberos V5 GSS mechanism RFC 1964">[RFC 1964] and in the SPKM
GSS Mechanism RFC 2025">[RFC 2025]), then any mechanism implementation should
be able to return the mech_type parameter for any uncorrupted input
token. If the mechanism implementation whose IDUP_Get_token_details()
function is being called does recognize the token, it can return any
further relevant information in the other token attributes, as
specified. In particular, this function can set has_SE_protection if
the SE calls may be used to unprotect it, or has_EV_protection if the
EV calls may be used to unprotect it, or both if both kinds of
protection have been applied (so that SE or EV calls may be used in
any order for unprotection) [note that GP calls, when supported,
should be usable for unprotection of any IDUP token].
IDUP_Get_token_details (which need not be supported by all underlying
mechanisms or implementations) gives only a hint about the content of
the token, there is no integrity check of any kind performed.
Regardless of the token type, it is possible to check that this
information is correct only by doing a proper unprotection of the
token. It is recommended that IDUP callers supply a token buffer at
least 4 KB in length in order to ensure that the desired data can
easily flow across this interface.
The OID of the mechanism and whether the token contains the
associated data is returned. In addition the size of the associated
data, whether inside or outside the token, is included if known.
[Note: data size will typically be unknown if the data was protected
using multibuffer calls. A value of "-1" may be used to indicate
"UNKNOWN".]
When the input token contains only an evidence generated
spontaneously, the following is returned:
- the evidence type;
- the Non-Repudiation policy under which the evidence was generated;
- the name of the generator of the evidence;
- the date and time when the evidence was generated (if available);
- the date and time when it was time stamped (if available).
When the input token contains only an evidence generated in response
to a request from another entity, the following additional
information is returned:
- an indicator to state that this evidence relates to a request;
- a string significant for the requester that will allow him to
check whether the answer corresponds to the requested evidence.
When the input token only contains a request, the following is
returned:
- the name of the requestor of the evidence,
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- the date and time when the request was made,
- the evidence type to send back,
- the non-repudiation policy under which the evidence to send back
should be generated,
- the names of the recipients which should generate and distribute
the requested evidence,
- the names of the recipients to whom the requested evidence should
be sent after it has been generated.
When the input token contains both evidence and a request, an
indicator is returned describing whether the new evidence should be
generated using only the data in the input token, or using both the
data and the evidence in the input token.
When the input token contains only CONF and DOA services, the
PIDU_Information bundle is returned. Other relevant parameters (such
as idu_size and time_stamping_time) may also be returned if this data
is available.
2.5.4. IDUP_Get_policy_info call
Inputs:
o policy_id OBJECT IDENTIFIER
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
o policy_version INTEGER,
o policy_effective_time INTEGER,
o policy_expiry_time INTEGER,
o supported_services SET OF Service_Descriptor,
-- services supported by this particular policy_id (equal to the
-- intersection of the services supported by the mechanisms
-- listed in supported_mechanisms)
o supported_mechanisms SET OF Mechanism_Descriptor
-- mechanisms supported by this particular policy_id
Return major_status codes:
o GSS_S_COMPLETE
-- policy_id recognized; all relevant fields have been returned.
o GSS_S_FAILURE
-- the policy_id was not recognized.
This call (which need not be supported by all underlying mechanisms
or implementations) allows the application to retrieve information
pertaining to a given policy_id. Policies define the following:
- rules for the protection of IDUs, such as trusted third
parties which may be involved in P-IDU generation, the roles in
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which they may be involved, and the duration for which the
generated P-IDU is valid;
- rules for the unprotection of P-IDUs, such as the interval
during which a trusted third party may legitimately declare its
key to have been compromised or revoked; and
- rules for adjudication, such as which authorities may be used
to adjudicate disputes.
The policy itself may be used by an adjudicator when resolving a
dispute. For example, the adjudicator might refer to the policy to
determine whether the rules for generation of the P-IDU have been
followed.
The following parameter bundles are associated with this call.
o Service_Descriptor PARAMETER BUNDLE,
o service_type OBJECT IDENTIFIER,
o service_validity_duration INTEGER,
o must_use_trusted_time BOOLEAN
o Mechanism_Descriptor PARAMETER BUNDLE,
o mechanism_type OBJECT IDENTIFIER,
o Authority_List PARAMETER BUNDLE,
o maximum_time_skew INTEGER
-- maximum permissible difference between P-IDU generation
-- time and the time of countersignature from a time
-- service (if required). This parameter is unused if
-- trusted time is not required.
o Authority_List PARAMETER BUNDLE,
o authority_name INTERNAL NAME,
o authority_role OCTET STRING,
o last_revocation_check_offset INTEGER
-- may be 0, greater than 0, or less than 0. The value of
-- this parameter is added to P-IDU generation time to
-- get latest time at which the mechanism will check to
-- see if this authority's key has been revoked.
An example of the use of the last parameter in Authority_List is as
follows. If an authority has a defined last_revocation_check_offset
of negative one hour, then all revocations taking effect earlier than
one hour before the generation of a P-IDU will render that P-IDU
invalid; no revocation taking place later than one hour before the
generation of the P-IDU will affect the P-IDU's validity.
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Note that both the maximum_time_skew and the
last_revocation_check_offset values are given in minutes.
2.5.5. IDUP_Cancel_multibuffer_op call
Inputs:
o env_handle ENVIRONMENT HANDLE,
Outputs:
o major_status INTEGER,
o minor_status INTEGER,
Return major_status codes:
o GSS_S_COMPLETE
-- operation cancelled; state purged.
o GSS_S_FAILURE
-- unable to cancel operation; state retained.
This call (which need not be supported by all underlying mechanisms
or implementations) allows the application to cancel a multibuffer
operation prior to normal completion (e.g., subsequent to calling
Start_operation and zero or more Process_operation, but prior to
calling End_operation). When successful, this call purges any
internal state information which would have been used to continue
processing for the full set of multibuffer calls.
3. Related Activities
In order to implement the IDUP-GSS-API atop existing, emerging, and
future security mechanisms, the following is necessary:
- object identifiers must be assigned to candidate IDUP-GSS-API
mechanisms and the name types which they support; and
- concrete data element (i.e., token and parameter bundle) formats
must be defined for candidate mechanisms.
Calling applications must implement formatting conventions which will
enable them to distinguish IDUP-GSS-API P-IDUs from other IDUs in
their environment.
Concrete language bindings are required for the programming
environments in which the IDUP-GSS-API is to be employed.
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4. Acknowledgments
Many thanks are due to Tim Moses and Dhanya Thakkar of Entrust
Technologies, Denis Pinkas of Bull, and David Kurn of Tandem
Computers for a number of helpful comments and contributions.
5. Security Considerations
Security issues are discussed throughout this memo.
6. REFERENCES
[MSP] U.S. National Security Agency, "Message Security
Protocol", Secure Data Network System SDN.701, March
1994.
RFC-1421">[RFC-1421] Linn, J., "Privacy Enhancement for Internet Electronic
Mail: Part I: Message Encryption and Authentication
Procedures", RFC 1421, February 1993.
RFC-2078">[RFC-2078] Linn, J., "Generic Security Service Application Program
Interface, Version 2", RFC 2078, January 1997..
RFC 1964">[RFC 1964] Linn, J, "The Kerberos Version 5 GSS-API Mechanism", RFC
1964, June 1996.
RFC 2025">[RFC 2025] Adams, C., "The Simple Public-Key GSS-API Mechanism
(SPKM)", RFC 2025, October 1996.
[ISO/IEC] 2nd ISO/IEC CD 13888-1, "Information technology -
Security techniques - Non-repudiation - Part 1: General
Model", ISO/IEC JTC 1/SC 27, May 30, 1995
7. Author's Address
Carlisle Adams
Entrust Technologies
750 Heron Road, Suite E08,
Ottawa, Ontario, CANADA K1V 1A7
Phone: +1 613.247.3180
EMail: cadams@entrust.com
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APPENDIX A: MECHANISM-INDEPENDENT TOKEN FORMAT
This appendix specifies the use, for IDUP-GSS-API tokens, of the
mechanism-independent level of encapsulating representation for
tokens given in Section 3.1 of GSS-API RFC-2078">[RFC-2078]. The
representation given there incorporates an identifier of the
mechanism type to be used when processing the associated tokens. Use
of that octet format is recommended to the designers of IDUP-GSS-API
implementations based on various mechanisms so that tokens can be
interpreted unambiguously at IDUP-GSS-API peers. It is recognized,
however, that for interoperability purposes with peers not using IDUP
for specific IDU protection/unprotection protocols, the encapsulating
representation may need to be omitted. (In such a case it is
necessary that the underlying mechanism provides some sort of
internal or external identification that allows it to recognize its
own tokens.) When the mechanism-independent level of encapsulating
representation is not desired, callers SHOULD set
mech_indep_encap_req to FALSE (note that some underlying mechanisms
may default this parameter to FALSE).
For purely descriptive purposes, the following simple ASN.1 structure
is used to illustrate the structural relationships among token and
tag objects. For interoperability purposes, token and tag encoding
shall be performed using the concrete encoding procedures described
in Section 3.1 of GSS-API RFC-2078">[RFC-2078].
-- top-level token definition to frame different mechanisms
IDUP-GSS-API DEFINITIONS ::=
BEGIN
MechType ::= OBJECT IDENTIFIER
Token ::= [APPLICATION 0] IMPLICIT SEQUENCE {
thisMech MechType,
token ANY DEFINED BY thisMech
-- contents mechanism-specific
}
END
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APPENDIX B: EXAMPLES OF IDUP USE
This appendix provides examples of the use of IDUP to do IDU
protection and unprotection. It should not be regarded as
constrictive to implementations or as defining the only means through
which IDUP-GSS-API functions can be realized with particular
underlying technology, and does not demonstrate all IDUP-GSS-API
features.
Most of the examples below only illustrate the use of CONF/DOA
protection services. Note that when both CONF/DOA and Evidence
services are required, calling applications may use a series of SE
and EV calls, or may use the GP calls (when these are supported).
Using the former approach implies multiple calls (e.g., the SE calls
are used to protect some data and the resulting token is then input
to the EV calls to add evidence information), but some callers may
find this to be more attractive than coding to the GP calls because
of the simpler SE/EV interface. Depending upon the underlying
mechanism, the series of SE/EV calls may result in a single token
that can be unprotected using the SE and EV calls in any order (for
example, because it is a single ASN.1 SEQUENCE that incorporates all
the specified protection services at one level), or the series may
result in a token that can only be unprotected in the reverse order
of protection (for example, because each SE/EV output token was
effectively embedded in the token of the subsequent call). The
IDUP_Get_token_details call can assist callers in determining how to
unprotect any received token.
B.1. Simple Mechanism, Single Buffer
To illustrate the simplest possible case, consider an underlying IDUP
mechanism which does straightforward encryption/decryption and
signing/verification only using public-key techniques; none of the
other possible services, such as creation of proof-of-origin
evidence, requests for proof-of-delivery evidence, or use of trusted
time, are supported. PEMRFC-1421">[RFC-1421] is one example of a mechanism
which fits this description. Furthermore (again for simplicity),
assume that encapsulation is chosen by the calling application during
IDU protection.
Such a mechanism would likely use the "SE" set of IDUP-GSS-API calls.
The following parameter bundle uses and defaults would therefore be
specified in the relevant IDUP mechanism document.
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SENDER:
Set
env_handle = environment handle in use;
idu_buffer = data buffer;
Target_Info.targ_names = receiver names;
Protect_Options = as necessary;
Call
IDUP_SE_SingleBuffer_Protect() with above input parameters
Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
Target_Info.Bad_Targ_Name,
(as required) for more detailed information.
Send
Output parameter pidu_buffer to receiver.
RECEIVER (any parameters not listed below are given the value NULL):
Set
env_handle = environment handle in use;
pidu_buffer = received data buffer;
Call
IDUP_SE_SingleBuffer_Unprotect() with above input parameters
Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
(as required) for more detailed information
Utilize
PIDU_Information.Protect_Options.Protect_Operation,
(to determine which services were applied by the originator)
PIDU_Information.Protect_Options.sign_qop_alg / enc_qop_alg,
(to determine the corresponding qualities of the services)
Prot_Information.originator_name,
(to determine the name of the originator)
Prot_Information.protection_time,
(to determine when the IDU was protected)
idu_buffer
(to retrieve the unprotected data).
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B.2. Simple Mechanism, Single Buffer (Again)
To illustrate a slight variation on the simplest possible case,
assume that everything is as in the previous scenario except that the
"GP" calls are used.
The following parameter bundle uses and defaults would therefore be
specified in the relevant IDUP mechanism document.
Mech_Specific_Info
- NOT USED (the only acceptable input, therefore, is NULL)
Idu_Sensitivity
- NOT USED (the only acceptable input, therefore, is NULL)
Service_Creation_Info
- NOT USED (the only acceptable input, therefore, is NULL)
Service_Verification_Info
- NOT USED (the only acceptable input, therefore, is NULL)
Quality
- the qop_algs parameter must be supported, with a suitable
DEFAULT value specified;
- suitable DEFAULT values for validity, policy_id, and
allow_policy_mapping must be specified (it may be an
implementation option as to whether these parameters are
explicitly modifiable by the calling application, or whether
NULLs are the only acceptable input)
Idu_Information
- the idu_type parameter must have a value representing a suitable
IDU type (for example, in PEM a value representing the string
"RFC822" or some other valid "Content-Domain" would be used),
with a suitable DEFAULT value specified;
- the idu_title parameter is NOT USED (the only acceptable input,
therefore, is NULL)
Prot_Information
- the originator_name and idu_type (in Idu_Information) parameters
are read from the encapsulating information and output by
IDUP_Start_Unprotect;
- all other parameters are NOT USED (and therefore NULL)
Special_Conditions
- NOT USED (the only acceptable input, therefore, is NULL)
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Target_Info
- this bundle is used as described in IDUP; no DEFAULT values are
specified
General_Service_Data
- the unencapsulated_token parameter is used if
encapsulation_request is FALSE;
- the minor_status parameter is used to return minor status values
as specified by the mechanism document
Prot_Service
- the prot_service_type parameter may have a value of "1"
("perform unsolicited service") or NULL (which specifies the
DEFAULT value of "1");
- the service_id parameter must have a value representing
"PER_CONF" or "PER_DOA";
- the parameters Service_Creation_Info, service_to,
Service_Verification_Info, and service_verification_info_id are
NOT USED (and therefore NULL)
Unprot_Service
- the unprot_service_type parameter will always have a value of
"1" ("receive unsolicited service");
- the service_id parameter will have a value representing
"REC_CONF" or "REC_DOA";
- the parameters service_verification_info_id,
Service_Verification_Info, service_to, and
Service_Creation_Info, are NOT USED (and therefore NULL)
Assuming that the calling application has only a single buffer of
data to protect/unprotect, the following sequence of operations must
be performed by the sender and receivers (subsequent to environment
establishment).
SENDER (any parameters not listed below are given the value NULL):
Set
env_handle = environment handle in use;
encapsulation_request = TRUE;
single_idu_buffer = data buffer;
Target_Info.targ_names = receiver names;
P_Services.Prot_Service_1.service_id = PER_CONF;
P_Services.Prot_Service_2.service_id = PER_DOA;
Call
IDUP_Start_Protect() with above input parameters
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Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
Target_Info.bad_targ_names / Target_Info.bad_targ_status,
P_Services.Prot_Service_1.General_Service_Data.minor_status,
P_Services.Prot_Service_2.General_Service_Data.minor_status
(as required) for more detailed information.
Send
Output parameter pidu_buffer to receiver.
RECEIVER (any parameters not listed below are given the value NULL):
Set
env_handle = environment handle in use;
single_pidu_buffer = received data buffer;
Call
IDUP_Start_Unprotect() with above input parameters
Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
R_Services.Unprot_Service_1.General_Service_Data.minor_status,
R_Services.Unprot_Service_2.General_Service_Data.minor_status
(as required) for more detailed information
Utilize
R_Services.Unprot_Service_1/2.service_id,
(to determine which services were applied by the originator)
R_Services.Unprot_Service_1/2.Quality,
(to determine the corresponding qualities of the services)
Prot_Information.originator_name,
(to determine the name of the originator)
single_idu_buffer
(to retrieve the unprotected data).
B.3. Simple Mechanism, Multiple Buffers
To illustrate the next step up in complexity, consider the use of the
simple IDUP mechanism described in B.2 above with multiple data
buffers. In particular, consider the case in which a large data file
is to be signed. For this example, assume that the calling
application does not wish to use encapsulation.
Note that the parameter bundle uses and defaults are as specified in
B.2. above.
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SENDER (any parameters not listed below are given the value NULL):
Set
env_handle = environment handle in use;
encapsulation_request = FALSE;
P_Services.Prot_Service.service_id = PER_DOA;
Call
IDUP_Start_Protect() with above input parameters
Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
P_Services.Prot_Service.General_Service_Data.minor_status
(as required) for more detailed information.
For each buffer of input data:
Set
input_buffer = buffer
Call
IDUP_Protect() with above input parameter
Check
major_status. If not GSS_S_COMPLETE, check
minor_status
Call
IDUP_End_Protect()
Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
P_Services.Prot_Service.General_Service_Data.minor_status
(as required) for more detailed information.
Send
P_Services.Prot_Service.General_Service_Data.unencapsulated_token,
and the file for which the signature was calculated (if required),
to receiver.
RECEIVER (any parameters not listed below are given the value NULL):
Set
env_handle = environment handle in use;
R_Services.Unprot_Service_1.General_Service_Data.
unencapsulated_token = received unencapsulated token;
Call
IDUP_Start_Unprotect() with above input parameters
Check
major_status. If not GSS_S_COMPLETE, check
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RFC 2479 IDUP-GSS-API December 1998
minor_status,
R_Services.Unprot_Service_1.General_Service_Data.minor_status,
(as required) for more detailed information
For each buffer of input data:
Set
input_buffer = buffer
Call
IDUP_Unprotect() with above input parameter
Check
major_status. If not GSS_S_COMPLETE, check
minor_status
Call
IDUP_End_Unprotect()
Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
R_Services.Unprot_Service_1.General_Service_Data.minor_status,
(as required) for more detailed information.
Utilize
R_Services.Unprot_Service_1.service_id,
(to determine which service was applied by the originator; note
that Unprot_Service_2 will have NULL in unprot_service_type
to indicate that it is not used)
R_Services.Unprot_Service_1.Quality,
(to determine the corresponding quality of the service)
Prot_Information.originator_name, (from IDUP_Start_Unprotect)
(to determine the name of the signer)
major_status (from IDUP_End_Unprotect)
(to determine pass/fail status of signature verification).
B.4. More Sophisticated Mechanism, Small Application Buffers
To illustrate a higher level of complexity, consider the use of a
more sophisticated IDUP mechanism and a calling application with
small data buffers. In particular, consider the case in which a very
small e-mail message is to be encrypted for a relatively large
receiver list (R), some subset of whom (r) will be asked to send
proofs of receipt of the message to some other subset (L) (which
includes the originator). So that the example is not unnecessarily
complicated, assume again that the originating application uses
encapsulation.
The uses and defaults for the various parameter bundles for this
mechanism would be specified in the relevant IDUP mechanism document
as follows.
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Mech_Specific_Info
- NOT USED (the only acceptable input, therefore, is NULL)
Idu_Sensitivity
- NOT USED (the only acceptable input, therefore, is NULL)
Service_Creation_Info
- used to create "proof of delivery" evidence (but actual
structure is opaque to calling application)
Service_Verification_Info
- used to verify "proof of delivery" evidence (but actual
structure is opaque to calling application)
Quality
- the qop_algs parameter must be supported, with a suitable
DEFAULT value specified;
- suitable DEFAULT values for validity, policy_id, and
allow_policy_mapping must be specified (it may be an
implementation option as to whether these parameters are
explicitly modifiable by the calling application, or whether
NULLs are the only acceptable input)
Idu_Information
- the idu_type parameter must have a value representing a suitable
IDU type, with a suitable DEFAULT value specified;
- the idu_title parameter must have a value representing a
suitable IDU title, with a suitable DEFAULT value specified
Prot_Information
- the originator_name, protection_time, and idu_type / idu_title
(in Idu_Information) parameters are read from the contained
header information and output by IDUP_Start_Unprotect;
Special_Conditions
- the parameter prot_oper_id is NOT USED (the only acceptable
input, therefore, is NULL);
- trusted or untrusted time may be selected by the calling
application, with a suitable DEFAULT value specified
Target_Info
- this bundle is used as described in IDUP; no DEFAULT values are
specified
General_Service_Data
- the unencapsulated_token parameter is used if
encapsulation_request is FALSE;
- the minor_status parameter is used to return minor status values
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as specified by the mechanism document
Prot_Service
- the prot_service_type parameter may have a value of "1"
("perform unsolicited service"), "2" ("perform solicited
service"), "3" (perform service solicitation), or NULL (which
specifies the DEFAULT value of "1");
- the service_id parameter must have a value representing
"PER_CONF", "PER_DOA", "PER_POO", or "PER_POD";
- the parameters Service_Creation_Info, service_to,
Service_Verification_Info, and service_verification_info_id are
used when required by the IDUP operation
Unprot_Service
- the unprot_service_type parameter may have a value of "1"
("receive unsolicited service"), "2" ("receive solicited
service"), or "3" (receive service solicitation);
- the service_id parameter will have a value representing
"REC_CONF", "REC_DOA", "REC_POO", or "REC_POD";
- the parameters service_verification_info_id,
Service_Verification_Info, service_to, and
Service_Creation_Info, are used when required by the IDUP
operation
SENDER (any parameters not listed below are given the value NULL):
Set
env_handle = environment handle in use;
Idu_Information.idu_type = value for "e-mail document";
Idu_Information.idu_title = "Contract 1234";
Special_Conditions.use_trusted_time = TRUE;
encapsulation_request = TRUE;
single_idu_buffer = very small e-mail message;
Target_Info.targ_names = receiver names (R);
Prot_Service_1.prot_service_type = "1";
Prot_Service_1.service_id = PER_CONF;
Prot_Service_2.prot_service_type = "3";
Prot_Service_2.service_id = PER_POD;
Prot_Service_2.General_Service_Data.Target_Info.targ_names
= "receipts from" list (r);
Prot_Service_2.service_to = "receipts to" list (L);
P_Services.Prot_Service_1 = Prot_Service_1;
P_Services.Prot_Service_2 = Prot_Service_2;
Call
IDUP_Start_Protect() with above input parameters
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RFC 2479 IDUP-GSS-API December 1998
Check
major_status. If not GSS_S_COMPLETE,
while major_status == IDUP_S_MORE_OUTBUFFER_NEEDED
Save
pidu_buffer,
Call
IDUP_Start_Protect() (to get next portion of pidu_buffer)
Check
major_status,
minor_status,
Target_Info.bad_targ_names / Target_Info.bad_targ_status,
P_Services.Prot_Service_1.General_Service_Data.minor_status,
P_Services.Prot_Service_2.General_Service_Data.minor_status
(as required) for more detailed information.
Save
Prot_Service_2.Service_Verification_Info,
Prot_Service_2.service_verification_info_id
Send
All saved buffers of pidu_buffer to receiver list (R).
RECEIVER (ON RECEIVER LIST (R)):
(any parameters not listed below are given the value NULL)
Set
env_handle = environment handle in use;
partial_pidu_buffer = initial buffer of received p-idu;
Call
IDUP_Start_Unprotect() with above input parameters
While major_status == IDUP_S_MORE_PIDU_NEEDED,
Set
partial_pidu_buffer = next buffer of p-idu
Call
IDUP_Start_Unprotect()
Check
major_status,
minor_status,
R_Services.Unprot_Service_1.General_Service_Data.minor_status,
R_Services.Unprot_Service_2.General_Service_Data.minor_status,
(as required) for more detailed information
Save
initial_idu_buffer (if non-empty)
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Set
input_buffer = remaining p-idu buffer
Call
IDUP_Unprotect() with above input parameter
Check
major_status. If not GSS_S_COMPLETE, check
minor_status
Save
output_buffer
Call
IDUP_End_Unprotect()
Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
R_Services.Unprot_Service_1.General_Service_Data.minor_status,
R_Services.Unprot_Service_2.General_Service_Data.minor_status,
(as required) for more detailed information.
Utilize
R_Services.Unprot_Service_1/2.service_id,
(to determine which services were applied by the originator)
R_Services.Unprot_Service_1/2.Quality,
(to determine the corresponding qualities of the service)
Prot_Information.originator_name/protection_time and
Prot_Information.Idu_Information.idu_type/idu_title,
(from IDUP_Start_Unprotect) (to determine originator info.)
R_Services.Unprot_Service_2.General_Service_Data.Target_Info.
targ.names, (to determine if rec. is in "receipts from" (r))
Service_Verification_Info/service_verification_info_id
(to determine if receiver is in "receipts to" list (L))
If receiver is in "receipts from" list (r)
Save
R_Services.Unprot_Service_2.service_to,
R_Services.Unprot_Service_2.Service_Creation_Info
If receiver is in "receipts to" list (L)
Save
Service_Verification_Info,
service_verification_info_id
RECEIVER (ON "RECEIPTS FROM" LIST (r)):
(procedure to generate receipt)
Set
env_handle = environment handle in use;
Target_Info.targ_names = service_to
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Prot_Service_1.prot_service_type = "2";
Prot_Service_1.service_id = "PER_POD";
Prot_Service_1.Service_Creation_Info = Service_Creation_Info;
P_Services.Prot_Service_1 = Prot_Service_1
Call
IDUP_Start_Protect() with above input parameters
Check
major_status. If not GSS_S_COMPLETE, check
minor_status,
P_Services.Prot_Service_1.General_Service_Data.minor_status
(as required) for more detailed information.
Send
pidu_buffer to "receipts to" list (L)
RECEIVER (ON "RECEIPTS TO" LIST (L)):
(procedure to process received receipt)
Set
env_handle = environment handle in use;
single_pidu_buffer = received p-idu buffer (if it fits in a single
buffer; otherwise use partial_pidu_buffer and make multiple
calls, as above)
Call
IDUP_Start_Unprotect() with above input parameters
If major_status == IDUP_S_SERV_VERIF_INFO_NEEDED
Utilize
R_Services.Unprot_Service_1.service_verification_info.id
(to assist in locating necessary Service_Verification_Info)
Set
R_Services.Unprot_Service_1.Service_Verification_Info
= Service_Verification_Info
Call
IDUP_Start_Unprotect() with above input parameters
Check
major_status,
minor_status,
R_Services.Unprot_Service_1.General_Service_Data.minor_status
(as required) for more detailed information.
Utilize
R_Services.Unprot_Service_1.service_id,
(to determine that this is a "proof of delivery" evidence)
R_Services.Unprot_Service_1.Quality,
Prot_Information.originator_name, (for evidence generator info.)
major_status (to determine pass/fail status of evi. verif.).
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Full Copyright Statement
Copyright (C) The Internet Society (1998). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS 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.
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