GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools

Problem, Formatting or Query -  Send Feedback

Was this page helpful?-10+1


rfc:rfc5653

Network Working Group M. Upadhyay Request for Comments: 5653 Google Obsoletes: 2853 S. Malkani Category: Standards Track ActivIdentity

                                                           August 2009
    Generic Security Service API Version 2: Java Bindings Update

Abstract

 The Generic Security Services Application Program Interface (GSS-API)
 offers application programmers uniform access to security services
 atop a variety of underlying cryptographic mechanisms.  This document
 updates the Java bindings for the GSS-API that are specified in
 "Generic Security Service API Version 2 : Java Bindings" (RFC 2853).
 This document obsoletes RFC 2853 by making specific and incremental
 clarifications and corrections to it in response to identification of
 transcription errors and implementation experience.
 The GSS-API is described at a language-independent conceptual level
 in "Generic Security Service Application Program Interface Version 2,
 Update 1" (RFC 2743).  The GSS-API allows a caller application to
 authenticate a principal identity, to delegate rights to a peer, and
 to apply security services such as confidentiality and integrity on a
 per-message basis.  Examples of security mechanisms defined for GSS-
 API are "The Simple Public-Key GSS-API Mechanism" (RFC 2025) and "The
 Kerberos Version 5 Generic Security Service Application Program
 Interface (GSS-API) Mechanism: Version 2" (RFC 4121).

Status of This Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (c) 2009 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents in effect on the date of
 publication of this document (http://trustee.ietf.org/license-info).
 Please review these documents carefully, as they describe your rights
 and restrictions with respect to this document.

Upadhyay & Malkani Standards Track [Page 1] RFC 5653 Java GSS-API Update August 2009

 This document may contain material from IETF Documents or IETF
 Contributions published or made publicly available before November
 10, 2008.  The person(s) controlling the copyright in some of this
 material may not have granted the IETF Trust the right to allow
 modifications of such material outside the IETF Standards Process.
 Without obtaining an adequate license from the person(s) controlling
 the copyright in such materials, this document may not be modified
 outside the IETF Standards Process, and derivative works of it may
 not be created outside the IETF Standards Process, except to format
 it for publication as an RFC or to translate it into languages other
 than English.

Table of Contents

 1. Introduction ....................................................6
 2. Conventions and Licenses ........................................7
 3. GSS-API Operational Paradigm ....................................8
 4. Additional Controls .............................................9
    4.1. Delegation ................................................10
    4.2. Mutual Authentication .....................................11
    4.3. Replay and Out-of-Sequence Detection ......................11
    4.4. Anonymous Authentication ..................................12
    4.5. Confidentiality ...........................................13
    4.6. Inter-process Context Transfer ............................13
    4.7. The Use of Incomplete Contexts ............................14
 5. Calling Conventions ............................................15
    5.1. Package Name ..............................................15
    5.2. Provider Framework ........................................15
    5.3. Integer Types .............................................16
    5.4. Opaque Data Types .........................................16
    5.5. Strings ...................................................16
    5.6. Object Identifiers ........................................16
    5.7. Object Identifier Sets ....................................17
    5.8. Credentials ...............................................17
    5.9. Contexts ..................................................19
    5.10. Authentication Tokens ....................................19
    5.11. Inter-Process Tokens .....................................20
    5.12. Error Reporting ..........................................20
         5.12.1. GSS Status Codes ..................................21
         5.12.2. Mechanism-Specific Status Codes ...................23
         5.12.3. Supplementary Status Codes ........................23
    5.13. Names ....................................................24
    5.14. Channel Bindings .........................................26
    5.15. Stream Objects ...........................................27
    5.16. Optional Parameters ......................................28
 6. Introduction to GSS-API Classes and Interfaces .................28
    6.1. GSSManager Class ..........................................28
    6.2. GSSName Interface .........................................29

Upadhyay & Malkani Standards Track [Page 2] RFC 5653 Java GSS-API Update August 2009

    6.3. GSSCredential Interface ...................................30
    6.4. GSSContext Interface ......................................30
    6.5. MessageProp Class .........................................31
    6.6. GSSException Class ........................................32
    6.7. Oid Class .................................................32
    6.8. ChannelBinding Class ......................................32
 7. Detailed GSS-API Class Description .............................33
    7.1. public abstract class GSSManager ..........................33
         7.1.1. Example Code .......................................34
         7.1.2. getInstance ........................................34
         7.1.3. getMechs ...........................................35
         7.1.4. getNamesForMech ....................................35
         7.1.5. getMechsForName ....................................35
         7.1.6. createName .........................................35
         7.1.7. createName .........................................36
         7.1.8. createName .........................................36
         7.1.9. createName .........................................37
         7.1.10. createCredential ..................................38
         7.1.11. createCredential ..................................38
         7.1.12. createCredential ..................................39
         7.1.13. createContext .....................................39
         7.1.14. createContext .....................................40
         7.1.15. createContext .....................................40
         7.1.16. addProviderAtFront ................................41
         7.1.17. Example Code ......................................41
         7.1.18. addProviderAtEnd ..................................42
         7.1.19. Example Code ......................................43
    7.2. public interface GSSName ..................................44
         7.2.1. Example Code .......................................44
         7.2.2. Static Constants ...................................45
         7.2.3. equals .............................................46
         7.2.4. equals .............................................46
         7.2.5. canonicalize .......................................46
         7.2.6. export .............................................47
         7.2.7. toString ...........................................47
         7.2.8. getStringNameType ..................................47
         7.2.9. isAnonymous ........................................47
         7.2.10. isMN ..............................................47
    7.3. public interface GSSCredential implements Cloneable .......47
         7.3.1. Example Code .......................................49
         7.3.2. Static Constants ...................................49
         7.3.3. dispose ............................................50
         7.3.4. getName ............................................50
         7.3.5. getName ............................................50
         7.3.6. getRemainingLifetime ...............................50
         7.3.7. getRemainingInitLifetime ...........................51
         7.3.8. getRemainingAcceptLifetime .........................51
         7.3.9. getUsage ...........................................51

Upadhyay & Malkani Standards Track [Page 3] RFC 5653 Java GSS-API Update August 2009

         7.3.10. getUsage ..........................................51
         7.3.11. getMechs ..........................................52
         7.3.12. add ...............................................52
         7.3.13. equals ............................................53
    7.4. public interface GSSContext ...............................53
         7.4.1. Example Code .......................................54
         7.4.2. Static Constants ...................................56
         7.4.3. initSecContext .....................................56
         7.4.4. Example Code .......................................57
         7.4.5. initSecContext .....................................58
         7.4.6. Example Code .......................................58
         7.4.7. acceptSecContext ...................................59
         7.4.8. Example Code .......................................60
         7.4.9. acceptSecContext ...................................61
         7.4.10. Example Code ......................................61
         7.4.11. isEstablished .....................................62
         7.4.12. dispose ...........................................62
         7.4.13. getWrapSizeLimit ..................................63
         7.4.14. wrap ..............................................63
         7.4.15. wrap ..............................................64
         7.4.16. unwrap ............................................65
         7.4.17. unwrap ............................................66
         7.4.18. getMIC ............................................67
         7.4.19. getMIC ............................................68
         7.4.20. verifyMIC .........................................68
         7.4.21. verifyMIC .........................................69
         7.4.22. export ............................................70
         7.4.23. requestMutualAuth .................................71
         7.4.24. requestReplayDet ..................................71
         7.4.25. requestSequenceDet ................................71
         7.4.26. requestCredDeleg ..................................71
         7.4.27. requestAnonymity ..................................72
         7.4.28. requestConf .......................................72
         7.4.29. requestInteg ......................................72
         7.4.30. requestLifetime ...................................73
         7.4.31. setChannelBinding .................................73
         7.4.32. getCredDelegState .................................73
         7.4.33. getMutualAuthState ................................73
         7.4.34. getReplayDetState .................................74
         7.4.35. getSequenceDetState ...............................74
         7.4.36. getAnonymityState .................................74
         7.4.37. isTransferable ....................................74
         7.4.38. isProtReady .......................................74
         7.4.39. getConfState ......................................75
         7.4.40. getIntegState .....................................75
         7.4.41. getLifetime .......................................75
         7.4.42. getSrcName ........................................75
         7.4.43. getTargName .......................................75

Upadhyay & Malkani Standards Track [Page 4] RFC 5653 Java GSS-API Update August 2009

         7.4.44. getMech ...........................................76
         7.4.45. getDelegCred ......................................76
         7.4.46. isInitiator .......................................76
    7.5. public class MessageProp ..................................76
         7.5.1. Constructors .......................................77
         7.5.2. getQOP .............................................77
         7.5.3. getPrivacy .........................................77
         7.5.4. getMinorStatus .....................................77
         7.5.5. getMinorString .....................................77
         7.5.6. setQOP .............................................78
         7.5.7. setPrivacy .........................................78
         7.5.8. isDuplicateToken ...................................78
         7.5.9. isOldToken .........................................78
         7.5.10. isUnseqToken ......................................78
         7.5.11. isGapToken ........................................78
         7.5.12. setSupplementaryStates ............................79
    7.6. public class ChannelBinding ...............................79
         7.6.1. Constructors .......................................80
         7.6.2. getInitiatorAddress ................................80
         7.6.3. getAcceptorAddress .................................80
         7.6.4. getApplicationData .................................81
         7.6.5. equals .............................................81
    7.7. public class Oid ..........................................81
         7.7.1. Constructors .......................................81
         7.7.2. toString ...........................................82
         7.7.3. equals .............................................82
         7.7.4. getDER .............................................82
         7.7.5. containedIn ........................................83
    7.8. public class GSSException extends Exception ...............83
         7.8.1. Static Constants ...................................83
         7.8.2. Constructors .......................................86
         7.8.3. getMajor ...........................................86
         7.8.4. getMinor ...........................................86
         7.8.5. getMajorString .....................................87
         7.8.6. getMinorString .....................................87
         7.8.7. setMinor ...........................................87
         7.8.8. toString ...........................................87
         7.8.9. getMessage .........................................87
 8. Sample Applications ............................................88
    8.1. Simple GSS Context Initiator ..............................88
    8.2. Simple GSS Context Acceptor ...............................92
 9. Security Considerations ........................................96
 10. Acknowledgments ...............................................96
 11. Changes since RFC 2853 ........................................97
 12. References ....................................................98
    12.1. Normative References .....................................98
    12.2. Informative References ...................................98

Upadhyay & Malkani Standards Track [Page 5] RFC 5653 Java GSS-API Update August 2009

1. Introduction

 This document specifies Java language bindings for the Generic
 Security Services Application Programming Interface version 2 (GSS-
 API).  GSS-API version 2 is described in a language-independent
 format in RFC 2743 [GSSAPIv2-UPDATE].  The GSS-API allows a caller
 application to authenticate a principal identity, to delegate rights
 to a peer, and to apply security services such as confidentiality and
 integrity on a per-message basis.
 This document and its predecessor, RFC 2853 [RFC2853], leverage the
 work done by the working group (WG) in the area of RFC 2743
 [GSSAPIv2-UPDATE] and the C-bindings of RFC 2744 [GSSAPI-Cbind].
 Whenever appropriate, text has been used from the C-bindings document
 (RFC 2744) to explain generic concepts and provide direction to the
 implementors.
 The design goals of this API have been to satisfy all the
 functionality defined in RFC 2743 [GSSAPIv2-UPDATE] and to provide
 these services in an object-oriented method.  The specification also
 aims to satisfy the needs of both types of Java application
 developers, those who would like access to a "system-wide" GSS-API
 implementation, as well as those who would want to provide their own
 "custom" implementation.
 A system-wide implementation is one that is available to all
 applications in the form of a library package.  It may be the
 standard package in the Java runtime environment (JRE) being used or
 it may be additionally installed and accessible to any application
 via the CLASSPATH.
 A custom implementation of the GSS-API, on the other hand, is one
 that would, in most cases, be bundled with the application during
 distribution.  It is expected that such an implementation would be
 meant to provide for some particular need of the application, such as
 support for some specific mechanism.
 The design of this API also aims to provide a flexible framework to
 add and manage GSS-API mechanisms.  GSS-API leverages the Java
 Cryptography Architecture (JCA) provider model to support the
 plugability of mechanisms.  Mechanisms can be added on a system-wide
 basis, where all users of the framework will have them available.
 The specification also allows for the addition of mechanisms per-
 instance of the GSS-API.
 Lastly, this specification presents an API that will naturally fit
 within the operation environment of the Java platform.  Readers are
 assumed to be familiar with both the GSS-API and the Java platform.

Upadhyay & Malkani Standards Track [Page 6] RFC 5653 Java GSS-API Update August 2009

2. Conventions and Licenses

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
 document are to be interpreted as described in [RFC2119].
 The following license applies to all code segments included in this
 specification.  If code is extracted from this specification, please
 include the following text in the code:

/* – Copyright © 2009 IETF Trust and the persons identified as – authors of the code. All rights reserved. – – Redistribution and use in source and binary forms, with or without – modification, are permitted provided that the following conditions – are met: – – - Redistributions of source code must retain the above copyright – notice, this list of conditions and the following disclaimer. – – - Redistributions in binary form must reproduce the above copyright – notice, this list of conditions and the following disclaimer in – the documentation and/or other materials provided with the – distribution. – – - Neither the name of Internet Society, IETF or IETF Trust, nor the – names of specific contributors, may be used to endorse or promote – products derived from this software without specific prior – written permission. – – THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND – CONTRIBUTORS 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, – INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF – MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE – DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS – BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, – EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED – TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, – DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON – ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, – OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY – OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE – POSSIBILITY OF SUCH DAMAGE. – – This code is part of RFC 5653; see the RFC itself for full legal – notices. */

Upadhyay & Malkani Standards Track [Page 7] RFC 5653 Java GSS-API Update August 2009

3. GSS-API Operational Paradigm

 "Generic Security Service Application Programming Interface, Version
 2" [GSSAPIv2-UPDATE] defines a generic security API to calling
 applications.  It allows a communicating application to authenticate
 the user associated with another application, to delegate rights to
 another application, and to apply security services such as
 confidentiality and integrity on a per-message basis.
 There are four stages to using GSS-API:
 1) The application acquires a set of credentials with which it may
    prove its identity to other processes.  The application's
    credentials vouch for its global identity, which may or may not be
    related to any local username under which it may be running.
 2) A pair of communicating applications establish a joint security
    context using their credentials.  The security context
    encapsulates shared state information, which is required in order
    that per-message security services may be provided.  Examples of
    state information that might be shared between applications as
    part of a security context are cryptographic keys and message
    sequence numbers.  As part of the establishment of a security
    context, the context initiator is authenticated to the responder,
    and may require that the responder is authenticated back to the
    initiator.  The initiator may optionally give the responder the
    right to initiate further security contexts, acting as an agent or
    delegate of the initiator.  This transfer of rights is termed
    "delegation", and is achieved by creating a set of credentials,
    similar to those used by the initiating application, but which may
    be used by the responder.
    A GSSContext object is used to establish and maintain the shared
    information that makes up the security context.  Certain
    GSSContext methods will generate a token, which applications treat
    as cryptographically protected, opaque data.  The caller of such a
    GSSContext method is responsible for transferring the token to the
    peer application, encapsulated if necessary in an application-to-
    application protocol.  On receipt of such a token, the peer
    application should pass it to a corresponding GSSContext method
    which will decode the token and extract the information, updating
    the security context state information accordingly.

Upadhyay & Malkani Standards Track [Page 8] RFC 5653 Java GSS-API Update August 2009

 3) Per-message services are invoked on a GSSContext object to apply
    either:
    integrity and data origin authentication, or
    confidentiality, integrity and data origin authentication
    to application data, which are treated by GSS-API as arbitrary
    octet-strings.  An application transmitting a message that it
    wishes to protect will call the appropriate GSSContext method
    (getMIC or wrap) to apply protection, and send the resulting token
    to the receiving application.  The receiver will pass the received
    token (and, in the case of data protected by getMIC, the
    accompanying message-data) to the corresponding decoding method of
    the GSSContext interface (verifyMIC or unwrap) to remove the
    protection and validate the data.
 4) At the completion of a communications session (which may extend
    across several transport connections), each application uses a
    GSSContext method to invalidate the security context and release
    any system or cryptographic resources held.  Multiple contexts may
    also be used (either successively or simultaneously) within a
    single communications association, at the discretion of the
    applications.

4. Additional Controls

 This section discusses the optional services that a context initiator
 may request of the GSS-API before the context establishment.  Each of
 these services is requested by calling the appropriate mutator method
 in the GSSContext object before the first call to init is performed.
 Only the context initiator can request context flags.
 The optional services defined are:
    Delegation: The (usually temporary) transfer of rights from
    initiator to acceptor, enabling the acceptor to authenticate
    itself as an agent of the initiator.
    Mutual Authentication: In addition to the initiator authenticating
    its identity to the context acceptor, the context acceptor should
    also authenticate itself to the initiator.
    Replay Detection: In addition to providing message integrity
    services, GSSContext per-message operations of getMIC and wrap
    should include message numbering information to enable verifyMIC
    and unwrap to detect if a message has been duplicated.

Upadhyay & Malkani Standards Track [Page 9] RFC 5653 Java GSS-API Update August 2009

    Out-of-Sequence Detection: In addition to providing message
    integrity services, GSSContext per-message operations (getMIC and
    wrap) should include message sequencing information to enable
    verifyMIC and unwrap to detect if a message has been received out
    of sequence.
    Anonymous Authentication: The establishment of the security
    context should not reveal the initiator's identity to the context
    acceptor.
 Some mechanisms may not support all optional services, and some
 mechanisms may only support some services in conjunction with others.
 The GSSContext interface offers query methods to allow the
 verification by the calling application of which services will be
 available from the context when the establishment phase is complete.
 In general, if the security mechanism is capable of providing a
 requested service, it should do so even if additional services must
 be enabled in order to provide the requested service.  If the
 mechanism is incapable of providing a requested service, it should
 proceed without the service leaving the application to abort the
 context establishment process if it considers the requested service
 to be mandatory.
 Some mechanisms may specify that support for some services is
 optional, and that implementors of the mechanism need not provide it.
 This is most commonly true of the confidentiality service, often
 because of legal restrictions on the use of data-encryption, but may
 apply to any of the services.  Such mechanisms are required to send
 at least one token from acceptor to initiator during context
 establishment when the initiator indicates a desire to use such a
 service, so that the initiating GSS-API can correctly indicate
 whether the service is supported by the acceptor's GSS-API.

4.1. Delegation

 The GSS-API allows delegation to be controlled by the initiating
 application via the requestCredDeleg method before the first call to
 init has been issued.  Some mechanisms do not support delegation, and
 for such mechanisms, attempts by an application to enable delegation
 are ignored.
 The acceptor of a security context, for which the initiator enabled
 delegation, can check if delegation was enabled by using the
 getCredDelegState method of the GSSContext interface.  In cases when
 it is enabled, the delegated credential object can be obtained by
 calling the getDelegCred method.  The obtained GSSCredential object
 may then be used to initiate subsequent GSS-API security contexts as
 an agent or delegate of the initiator.  If the original initiator's

Upadhyay & Malkani Standards Track [Page 10] RFC 5653 Java GSS-API Update August 2009

 identity is "A" and the delegate's identity is "B", then, depending
 on the underlying mechanism, the identity embodied by the delegated
 credential may be either "A" or "B acting for A".
 For many mechanisms that support delegation, a simple boolean does
 not provide enough control.  Examples of additional aspects of
 delegation control that a mechanism might provide to an application
 are duration of delegation, network addresses from which delegation
 is valid, and constraints on the tasks that may be performed by a
 delegate.  Such controls are presently outside the scope of the GSS-
 API.  GSS-API implementations supporting mechanisms offering
 additional controls should provide extension routines that allow
 these controls to be exercised (perhaps by modifying the initiator's
 GSS-API credential object prior to its use in establishing a
 context).  However, the simple delegation control provided by GSS-API
 should always be able to override other mechanism-specific delegation
 controls.  If the application instructs the GSSContext object that
 delegation is not desired, then the implementation must not permit
 delegation to occur.  This is an exception to the general rule that a
 mechanism may enable services even if they are not requested --
 delegation may only be provided at the explicit request of the
 application.

4.2. Mutual Authentication

 Usually, a context acceptor will require that a context initiator
 authenticate itself so that the acceptor may make an access-control
 decision prior to performing a service for the initiator.  In some
 cases, the initiator may also request that the acceptor authenticate
 itself.  GSS-API allows the initiating application to request this
 mutual authentication service by calling the requestMutualAuth method
 of the GSSContext interface with a "true" parameter before making the
 first call to init.  The initiating application is informed as to
 whether or not the context acceptor has authenticated itself.  Note
 that some mechanisms may not support mutual authentication, and other
 mechanisms may always perform mutual authentication, whether or not
 the initiating application requests it.  In particular, mutual
 authentication may be required by some mechanisms in order to support
 replay or out-of-sequence message detection, and for such mechanisms,
 a request for either of these services will automatically enable
 mutual authentication.

4.3. Replay and Out-of-Sequence Detection

 The GSS-API may provide detection of mis-ordered messages once a
 security context has been established.  Protection may be applied to
 messages by either application, by calling either getMIC or wrap

Upadhyay & Malkani Standards Track [Page 11] RFC 5653 Java GSS-API Update August 2009

 methods of the GSSContext interface, and verified by the peer
 application by calling verifyMIC or unwrap for the peer's GSSContext
 object.
 The getMIC method calculates a cryptographic checksum of an
 application message, and returns that checksum in a token.  The
 application should pass both the token and the message to the peer
 application, which presents them to the verifyMIC method of the
 peer's GSSContext object.
 The wrap method calculates a cryptographic checksum of an application
 message, and places both the checksum and the message inside a single
 token.  The application should pass the token to the peer
 application, which presents it to the unwrap method of the peer's
 GSSContext object to extract the message and verify the checksum.
 Either pair of routines may be capable of detecting out-of-sequence
 message delivery or the duplication of messages.  Details of such
 mis-ordered messages are indicated through supplementary query
 methods of the MessageProp object that is filled in by each of these
 routines.
 A mechanism need not maintain a list of all tokens that have been
 processed in order to support these status codes.  A typical
 mechanism might retain information about only the most recent "N"
 tokens processed, allowing it to distinguish duplicates and missing
 tokens within the most recent "N" messages; the receipt of a token
 older than the most recent "N" would result in the isOldToken method
 of the instance of MessageProp to return "true".

4.4. Anonymous Authentication

 In certain situations, an application may wish to initiate the
 authentication process to authenticate a peer, without revealing its
 own identity.  As an example, consider an application providing
 access to a database containing medical information and offering
 unrestricted access to the service.  A client of such a service might
 wish to authenticate the service (in order to establish trust in any
 information retrieved from it), but might not wish the service to be
 able to obtain the client's identity (perhaps due to privacy concerns
 about the specific inquiries, or perhaps simply to avoid being placed
 on mailing-lists).
 In normal use of the GSS-API, the initiator's identity is made
 available to the acceptor as a result of the context establishment
 process.  However, context initiators may request that their identity
 not be revealed to the context acceptor.  Many mechanisms do not
 support anonymous authentication, and for such mechanisms, the

Upadhyay & Malkani Standards Track [Page 12] RFC 5653 Java GSS-API Update August 2009

 request will not be honored.  An authentication token will still be
 generated, but the application is always informed if a requested
 service is unavailable, and has the option to abort context
 establishment if anonymity is valued above the other security
 services that would require a context to be established.
 In addition to informing the application that a context is
 established anonymously (via the isAnonymous method of the GSSContext
 class), the getSrcName method of the acceptor's GSSContext object
 will, for such contexts, return a reserved internal-form name,
 defined by the implementation.
 The toString method for a GSSName object representing an anonymous
 entity will return a printable name.  The returned value will be
 syntactically distinguishable from any valid principal name supported
 by the implementation.  The associated name-type object identifier
 will be an oid representing the value of NT_ANONYMOUS.  This name-
 type oid will be defined as a public, static Oid object of the
 GSSName class.  The printable form of an anonymous name should be
 chosen such that it implies anonymity, since this name may appear in,
 for example, audit logs.  For example, the string "<anonymous>" might
 be a good choice, if no valid printable names supported by the
 implementation can begin with "<" and end with ">".
 When using the equal method of the GSSName interface, and one of the
 operands is a GSSName instance representing an anonymous entity, the
 method must return "false".

4.5. Confidentiality

 If a GSSContext supports the confidentiality service, wrap method may
 be used to encrypt application messages.  Messages are selectively
 encrypted, under the control of the setPrivacy method of the
 MessageProp object used in the wrap method.

4.6. Inter-process Context Transfer

 GSS-APIv2 provides functionality that allows a security context to be
 transferred between processes on a single machine.  These are
 implemented using the export method of GSSContext and a byte array
 constructor of the same class.  The most common use for such a
 feature is a client-server design where the server is implemented as
 a single process that accepts incoming security contexts, which then
 launches child processes to deal with the data on these contexts.  In
 such a design, the child processes must have access to the security
 context object created within the parent so that they can use per-
 message protection services and delete the security context when the
 communication session ends.

Upadhyay & Malkani Standards Track [Page 13] RFC 5653 Java GSS-API Update August 2009

 Since the security context data structure is expected to contain
 sequencing information, it is impractical in general to share a
 context between processes.  Thus, the GSSContext interface provides
 an export method that the process, which currently owns the context,
 can call to declare that it has no intention to use the context
 subsequently, and to create an inter-process token containing
 information needed by the adopting process to successfully recreate
 the context.  After successful completion of export, the original
 security context is made inaccessible to the calling process by GSS-
 API, and any further usage of this object will result in failures.
 The originating process transfers the inter-process token to the
 adopting process, which creates a new GSSContext object using the
 byte array constructor.  The properties of the context are equivalent
 to that of the original context.
 The inter-process token may contain sensitive data from the original
 security context (including cryptographic keys).  Applications using
 inter-process tokens to transfer security contexts must take
 appropriate steps to protect these tokens in transit.
 Implementations are not required to support the inter-process
 transfer of security contexts.  Calling the isTransferable method of
 the GSSContext interface will indicate if the context object is
 transferable.

4.7. The Use of Incomplete Contexts

 Some mechanisms may allow the per-message services to be used before
 the context establishment process is complete.  For example, a
 mechanism may include sufficient information in its initial context-
 level tokens for the context acceptor to immediately decode messages
 protected with wrap or getMIC.  For such a mechanism, the initiating
 application need not wait until subsequent context-level tokens have
 been sent and received before invoking the per-message protection
 services.
 An application can invoke the isProtReady method of the GSSContext
 class to determine if the per-message services are available in
 advance of complete context establishment.  Applications wishing to
 use per-message protection services on partially established contexts
 should query this method before attempting to invoke wrap or getMIC.

Upadhyay & Malkani Standards Track [Page 14] RFC 5653 Java GSS-API Update August 2009

5. Calling Conventions

 Java provides the implementors with not just a syntax for the
 language, but also an operational environment.  For example, memory
 is automatically managed and does not require application
 intervention.  These language features have allowed for a simpler API
 and have led to the elimination of certain GSS-API functions.
 Moreover, the JCA defines a provider model that allows for
 implementation-independent access to security services.  Using this
 model, applications can seamlessly switch between different
 implementations and dynamically add new services.  The GSS-API
 specification leverages these concepts by the usage of providers for
 the mechanism implementations.

5.1. Package Name

 The classes and interfaces defined in this document reside in the
 package called "org.ietf.jgss".  Applications that wish to make use
 of this API should import this package name as shown in section 8.

5.2. Provider Framework

 The Java security API's use a provider architecture that allows
 applications to be implementation independent and security API
 implementations to be modular and extensible.  The
 java.security.Provider class is an abstract class that a vendor
 extends.  This class maps various properties that represent different
 security services that are available to the names of the actual
 vendor classes that implement those services.  When requesting a
 service, an application simply specifies the desired provider and the
 API delegates the request to service classes available from that
 provider.
 Using the Java security provider model insulates applications from
 implementation details of the services they wish to use.
 Applications can switch between providers easily and new providers
 can be added as needed, even at runtime.
 The GSS-API may use providers to find components for specific
 underlying security mechanisms.  For instance, a particular provider
 might contain components that will allow the GSS-API to support the
 Kerberos v5 mechanism [RFC4121] and another might contain components
 to support the Simple Public-Key GSS-API Mechanism (SPKM) [RFC2025].
 By delegating mechanism-specific functionality to the components
 obtained from providers, the GSS-API can be extended to support an
 arbitrary list of mechanism.

Upadhyay & Malkani Standards Track [Page 15] RFC 5653 Java GSS-API Update August 2009

 How the GSS-API locates and queries these providers is beyond the
 scope of this document and is being deferred to a Service Provider
 Interface (SPI) specification.  The availability of such an SPI
 specification is not mandatory for the adoption of this API
 specification nor is it mandatory to use providers in the
 implementation of a GSS-API framework.  However, by using the
 provider framework together with an SPI specification, one can create
 an extensible and implementation-independent GSS-API framework.

5.3. Integer Types

 All numeric values are declared as "int" primitive Java type.  The
 Java specification guarantees that this will be a 32-bit two's
 complement signed number.
 Throughout this API, the "boolean" primitive Java type is used
 wherever a boolean value is required or returned.

5.4. Opaque Data Types

 Java byte arrays are used to represent opaque data types that are
 consumed and produced by the GSS-API in the form of tokens.  Java
 arrays contain a length field that enables the users to easily
 determine their size.  The language has automatic garbage collection
 that alleviates the need by developers to release memory and
 simplifies buffer ownership issues.

5.5. Strings

 The String object will be used to represent all textual data.  The
 Java String object transparently treats all characters as two-byte
 Unicode characters, which allows support for many locals.  All
 routines returning or accepting textual data will use the String
 object.

5.6. Object Identifiers

 An Oid object will be used to represent Universal Object Identifiers
 (Oids).  Oids are ISO-defined, hierarchically globally interpretable
 identifiers used within the GSS-API framework to identify security
 mechanisms and name formats.  The Oid object can be created from a
 string representation of its dot notation (e.g., "1.3.6.1.5.6.2") as
 well as from its ASN.1 DER encoding.  Methods are also provided to
 test equality and provide the DER representation for the object.

Upadhyay & Malkani Standards Track [Page 16] RFC 5653 Java GSS-API Update August 2009

 An important feature of the Oid class is that its instances are
 immutable -- i.e., there are no methods defined that allow one to
 change the contents of an Oid.  This property allows one to treat
 these objects as "statics" without the need to perform copies.
 Certain routines allow the usage of a default oid.  A "null" value
 can be used in those cases.

5.7. Object Identifier Sets

 The Java bindings represent object identifier sets as arrays of Oid
 objects.  All Java arrays contain a length field, which allows for
 easy manipulation and reference.
 In order to support the full functionality of RFC 2743 [GSSAPIv2-
 UPDATE], the Oid class includes a method that checks for existence of
 an Oid object within a specified array.  This is equivalent in
 functionality to gss_test_oid_set_member.  The use of Java arrays and
 Java's automatic garbage collection has eliminated the need for the
 following routines: gss_create_empty_oid_set, gss_release_oid_set,
 and gss_add_oid_set_member.  Java GSS-API implementations will not
 contain them.  Java's automatic garbage collection and the immutable
 property of the Oid object eliminates the memory management issues of
 the C counterpart.
 Whenever a default value for an Object Identifier Set is required, a
 "null" value can be used.  Please consult the detailed method
 description for details.

5.8. Credentials

 GSS-API credentials are represented by the GSSCredential interface.
 The interface contains several constructs to allow for the creation
 of most common credential objects for the initiator and the acceptor.
 Comparisons are performed using the interface's "equals" method.  The
 following general description of GSS-API credentials is included from
 the C-bindings specification:
    GSS-API credentials can contain mechanism-specific principal
    authentication data for multiple mechanisms.  A GSS-API credential
    is composed of a set of credential-elements, each of which is
    applicable to a single mechanism.  A credential may contain at
    most one credential-element for each supported mechanism.  A
    credential-element identifies the data needed by a single
    mechanism to authenticate a single principal, and conceptually
    contains two credential-references that describe the actual
    mechanism-specific authentication data, one to be used by GSS-API
    for initiating contexts, and one to be used for accepting

Upadhyay & Malkani Standards Track [Page 17] RFC 5653 Java GSS-API Update August 2009

    contexts.  For mechanisms that do not distinguish between acceptor
    and initiator credentials, both references would point to the same
    underlying mechanism-specific authentication data.
 Credentials describe a set of mechanism-specific principals, and give
 their holder the ability to act as any of those principals.  All
 principal identities asserted by a single GSS-API credential should
 belong to the same entity, although enforcement of this property is
 an implementation-specific matter.  A single GSSCredential object
 represents all the credential elements that have been acquired.
 The creation of an GSSContext object allows the value of "null" to be
 specified as the GSSCredential input parameter.  This will indicate a
 desire by the application to act as a default principal.  While
 individual GSS-API implementations are free to determine such default
 behavior as appropriate to the mechanism, the following default
 behavior by these routines is recommended for portability:
 For the initiator side of the context:
 1) If there is only a single principal capable of initiating security
    contexts for the chosen mechanism that the application is
    authorized to act on behalf of, then that principal shall be used;
    otherwise,
 2) If the platform maintains a concept of a default network-identity
    for the chosen mechanism, and if the application is authorized to
    act on behalf of that identity for the purpose of initiating
    security contexts, then the principal corresponding to that
    identity shall be used; otherwise,
 3) If the platform maintains a concept of a default local identity,
    and provides a means to map local identities into network-
    identities for the chosen mechanism, and if the application is
    authorized to act on behalf of the network-identity image of the
    default local identity for the purpose of initiating security
    contexts using the chosen mechanism, then the principal
    corresponding to that identity shall be used; otherwise,
 4) A user-configurable default identity should be used.
 For the acceptor side of the context:
 1) If there is only a single authorized principal identity capable of
    accepting security contexts for the chosen mechanism, then that
    principal shall be used; otherwise,

Upadhyay & Malkani Standards Track [Page 18] RFC 5653 Java GSS-API Update August 2009

 2) If the mechanism can determine the identity of the target
    principal by examining the context-establishment token processed
    during the accept method, and if the accepting application is
    authorized to act as that principal for the purpose of accepting
    security contexts using the chosen mechanism, then that principal
    identity shall be used; otherwise,
 3) If the mechanism supports context acceptance by any principal, and
    if mutual authentication was not requested, any principal that the
    application is authorized to accept security contexts under using
    the chosen mechanism may be used; otherwise,
 4) A user-configurable default identity shall be used.
 The purpose of the above rules is to allow security contexts to be
 established by both initiator and acceptor using the default behavior
 whenever possible.  Applications requesting default behavior are
 likely to be more portable across mechanisms and implementations than
 ones that instantiate an GSSCredential object representing a specific
 identity.

5.9. Contexts

 The GSSContext interface is used to represent one end of a GSS-API
 security context, storing state information appropriate to that end
 of the peer communication, including cryptographic state information.
 The instantiation of the context object is done differently by the
 initiator and the acceptor.  After the context has been instantiated,
 the initiator may choose to set various context options that will
 determine the characteristics of the desired security context.  When
 all the application-desired characteristics have been set, the
 initiator will call the initSecContext method, which will produce a
 token for consumption by the peer's acceptSecContext method.  It is
 the responsibility of the application to deliver the authentication
 token(s) between the peer applications for processing.  Upon
 completion of the context-establishment phase, context attributes can
 be retrieved, by both the initiator and acceptor, using the accessor
 methods.  These will reflect the actual attributes of the established
 context.  At this point, the context can be used by the application
 to apply cryptographic services to its data.

5.10. Authentication Tokens

 A token is a caller-opaque type that GSS-API uses to maintain
 synchronization between each end of the GSS-API security context.
 The token is a cryptographically protected octet-string, generated by

Upadhyay & Malkani Standards Track [Page 19] RFC 5653 Java GSS-API Update August 2009

 the underlying mechanism at one end of a GSS-API security context for
 use by the peer mechanism at the other end.  Encapsulation (if
 required) within the application protocol and transfer of the token
 are the responsibility of the peer applications.
 Java GSS-API uses byte arrays to represent authentication tokens.
 Overloaded methods exist that allow the caller to supply input and
 output streams that will be used for the reading and writing of the
 token data.

5.11. Inter-Process Tokens

 Certain GSS-API routines are intended to transfer data between
 processes in multi-process programs.  These routines use a caller-
 opaque octet-string, generated by the GSS-API in one process for use
 by the GSS-API in another process.  The calling application is
 responsible for transferring such tokens between processes.  Note
 that, while GSS-API implementors are encouraged to avoid placing
 sensitive information within inter-process tokens, or to
 cryptographically protect them, many implementations will be unable
 to avoid placing key material or other sensitive data within them.
 It is the application's responsibility to ensure that inter-process
 tokens are protected in transit, and transferred only to processes
 that are trustworthy.  An inter-process token is represented using a
 byte array emitted from the export method of the GSSContext
 interface.  The receiver of the inter-process token would initialize
 an GSSContext object with this token to create a new context.  Once a
 context has been exported, the GSSContext object is invalidated and
 is no longer available.

5.12. Error Reporting

 RFC 2743 [GSSAPIv2-UPDATE] defined the usage of major and minor
 status values for the signaling of GSS-API errors.  The major code,
 also called GSS status code, is used to signal errors at the GSS-API
 level, independent of the underlying mechanism(s).  The minor status
 value or Mechanism status code, is a mechanism-defined error value
 indicating a mechanism-specific error code.
 Java GSS-API uses exceptions implemented by the GSSException class to
 signal both minor and major error values.  Both mechanism-specific
 errors and GSS-API level errors are signaled through instances of
 this class.  The usage of exceptions replaces the need for major and
 minor codes to be used within the API calls.  The GSSException class
 also contains methods to obtain textual representations for both the
 major and minor values, which is equivalent to the functionality of
 gss_display_status.

Upadhyay & Malkani Standards Track [Page 20] RFC 5653 Java GSS-API Update August 2009

5.12.1. GSS Status Codes

 GSS status codes indicate errors that are independent of the
 underlying mechanism(s) used to provide the security service.  The
 errors that can be indicated via a GSS status code are generic API
 routine errors (errors that are defined in the GSS-API
 specification).  These bindings take advantage of the Java exceptions
 mechanism, thus, eliminating the need for calling errors.
 A GSS status code indicates a single fatal generic API error from the
 routine that has thrown the GSSException.  Using exceptions announces
 that a fatal error has occurred during the execution of the method.
 The GSS-API operational model also allows for the signaling of
 supplementary status information from the per-message calls.  These
 need to be handled as return values since using exceptions is not
 appropriate for informatory or warning-like information.  The methods
 that are capable of producing supplementary information are the two
 per-message methods GSSContext.verifyMIC() and GSSContext.unwrap().
 These methods fill the supplementary status codes in the MessageProp
 object that was passed in.
 A GSSException object, along with providing the functionality for
 setting of the various error codes and translating them into textual
 representation, also contains the definitions of all the numeric
 error values.  The following table lists the definitions of error
 codes:
    Table: GSS Status Codes
    Name                   Value   Meaning
    BAD_BINDINGS             1     Incorrect channel bindings were
                                   supplied.
    BAD_MECH                 2     An unsupported mechanism
                                   was requested.
    BAD_NAME                 3     An invalid name was supplied.
    BAD_NAMETYPE             4     A supplied name was of an
                                   unsupported type.
    BAD_STATUS               5     An invalid status code was
                                   supplied.
    BAD_MIC                  6     A token had an invalid MIC.
    CONTEXT_EXPIRED          7     The context has expired.

Upadhyay & Malkani Standards Track [Page 21] RFC 5653 Java GSS-API Update August 2009

    CREDENTIALS_EXPIRED      8     The referenced credentials
                                   have expired.
    DEFECTIVE_CREDENTIAL     9     A supplied credential was
                                   invalid.
    DEFECTIVE_TOKEN         10     A supplied token was invalid.
    FAILURE                 11     Miscellaneous failure,
                                   unspecified at the GSS-API
                                   level.
    NO_CONTEXT              12     Invalid context has been
                                   supplied.
    NO_CRED                 13     No credentials were supplied, or
                                   the credentials were unavailable
                                   or inaccessible.
    BAD_QOP                 14     The quality-of-protection (QOP)
                                   requested could not be provided.
    UNAUTHORIZED            15     The operation is forbidden by
                                   the local security policy.
    UNAVAILABLE             16     The operation or option is
                                   unavailable.
    DUPLICATE_ELEMENT       17     The requested credential
                                   element already exists.
    NAME_NOT_MN             18     The provided name was not a
                                   mechanism name.
    The following four status codes (DUPLICATE_TOKEN, OLD_TOKEN,
    UNSEQ_TOKEN, and GAP_TOKEN) are contained in a GSSException
    only if detected during context establishment, in which case it
    is a fatal error. (During per-message calls, these values are
    indicated as supplementary information contained in the
    MessageProp object.) They are:
    DUPLICATE_TOKEN         19     The token was a duplicate of an
                                   earlier version.
    OLD_TOKEN               20     The token's validity period has
                                   expired.

Upadhyay & Malkani Standards Track [Page 22] RFC 5653 Java GSS-API Update August 2009

    UNSEQ_TOKEN             21     A later token has already been
                                   processed.
    GAP_TOKEN               22     The expected token was not
                                   received.
 The GSS major status code of FAILURE is used to indicate that the
 underlying mechanism detected an error for which no specific GSS
 status code is defined.  The mechanism-specific status code can
 provide more details about the error.
 The different major status codes that can be contained in the
 GSSException object thrown by the methods in this specification are
 the same as the major status codes returned by the corresponding
 calls in RFC 2743 [GSSAPIv2-UPDATE].

5.12.2. Mechanism-Specific Status Codes

 Mechanism-specific status codes are communicated in two ways, they
 are part of any GSSException thrown from the mechanism-specific layer
 to signal a fatal error, or they are part of the MessageProp object
 that the per-message calls use to signal non-fatal errors.
 A default value of 0 in either the GSSException object or the
 MessageProp object will be used to represent the absence of any
 mechanism-specific status code.

5.12.3. Supplementary Status Codes

 Supplementary status codes are confined to the per-message methods of
 the GSSContext interface.  Because of the informative nature of these
 errors it is not appropriate to use exceptions to signal them.
 Instead, the per-message operations of the GSSContext interface
 return these values in a MessageProp object.
 The MessageProp class defines query methods that return boolean
 values indicating the following supplementary states:
    Table: Supplementary Status Methods
    Method Name        Meaning when "true" is returned
    isDuplicateToken   The token was a duplicate of an
                       earlier token.
    isOldToken         The token's validity period has
                       expired.

Upadhyay & Malkani Standards Track [Page 23] RFC 5653 Java GSS-API Update August 2009

    isUnseqToken       A later token has already been
                       processed.
    isGapToken         An expected per-message token was
                       not received.
 A "true" return value for any of the above methods indicates that the
 token exhibited the specified property.  The application must
 determine the appropriate course of action for these supplementary
 values.  They are not treated as errors by the GSS-API.

5.13. Names

 A name is used to identify a person or entity.  GSS-API authenticates
 the relationship between a name and the entity claiming the name.
 Since different authentication mechanisms may employ different
 namespaces for identifying their principals, GSS-API's naming support
 is necessarily complex in multi-mechanism environments (or even in
 some single-mechanism environments where the underlying mechanism
 supports multiple namespaces).
 Two distinct conceptual representations are defined for names:
 1) A GSS-API form represented by implementations of the GSSName
    interface: A single GSSName object may contain multiple names from
    different namespaces, but all names should refer to the same
    entity.  An example of such an internal name would be the name
    returned from a call to the getName method of the GSSCredential
    interface, when applied to a credential containing credential
    elements for multiple authentication mechanisms employing
    different namespaces.  This GSSName object will contain a distinct
    name for the entity for each authentication mechanism.
    For GSS-API implementations supporting multiple namespaces,
    GSSName implementations must contain sufficient information to
    determine the namespace to which each primitive name belongs.
 2) Mechanism-specific contiguous byte array and string forms:
    Different GSSName initialization methods are provided to handle
    both byte array and string formats and to accommodate various
    calling applications and name types.  These formats are capable of
    containing only a single name (from a single namespace).
    Contiguous string names are always accompanied by an object
    identifier specifying the namespace to which the name belongs, and
    their format is dependent on the authentication mechanism that
    employs that name.  The string name forms are assumed to be
    printable, and may therefore be used by GSS-API applications for

Upadhyay & Malkani Standards Track [Page 24] RFC 5653 Java GSS-API Update August 2009

    communication with their users.  The byte array name formats are
    assumed to be in non-printable formats (e.g., the byte array
    returned from the export method of the GSSName interface).
 A GSSName object can be converted to a contiguous representation by
 using the toString method.  This will guarantee that the name will be
 converted to a printable format.  Different initialization methods in
 the GSSName interface are defined allowing support for multiple
 syntaxes for each supported namespace, and allowing users the freedom
 to choose a preferred name representation.  The toString method
 should use an implementation-chosen printable syntax for each
 supported name type.  To obtain the printable name type,
 getStringNameType method can be used.
 There is no guarantee that calling the toString method on the GSSName
 interface will produce the same string form as the original imported
 string name.  Furthermore, it is possible that the name was not even
 constructed from a string representation.  The same applies to
 namespace identifiers, which may not necessarily survive unchanged
 after a journey through the internal name form.  An example of this
 might be a mechanism that authenticates X.500 names, but provides an
 algorithmic mapping of Internet DNS names into X.500.  That
 mechanism's implementation of GSSName might, when presented with a
 DNS name, generate an internal name that contained both the original
 DNS name and the equivalent X.500 name.  Alternatively, it might only
 store the X.500 name.  In the latter case, the toString method of
 GSSName would most likely generate a printable X.500 name, rather
 than the original DNS name.
 The context acceptor can obtain a GSSName object representing the
 entity performing the context initiation (through the usage of
 getSrcName method).  Since this name has been authenticated by a
 single mechanism, it contains only a single name (even if the
 internal name presented by the context initiator to the GSSContext
 object had multiple components).  Such names are termed internal-
 mechanism names (or MNs), and the names emitted by GSSContext
 interface in the getSrcName and getTargName are always of this type.
 Since some applications may require MNs without wanting to incur the
 overhead of an authentication operation, creation methods are
 provided that take not only the name buffer and name type, but also
 the mechanism oid for which this name should be created.  When
 dealing with an existing GSSName object, the canonicalize method may
 be invoked to convert a general internal name into an MN.
 GSSName objects can be compared using their equal method, which
 returns "true" if the two names being compared refer to the same
 entity.  This is the preferred way to perform name comparisons
 instead of using the printable names that a given GSS-API

Upadhyay & Malkani Standards Track [Page 25] RFC 5653 Java GSS-API Update August 2009

 implementation may support.  Since GSS-API assumes that all primitive
 names contained within a given internal name refer to the same
 entity, equal can return "true" if the two names have at least one
 primitive name in common.  If the implementation embodies knowledge
 of equivalence relationships between names taken from different
 namespaces, this knowledge may also allow successful comparisons of
 internal names containing no overlapping primitive elements.
 When used in large access control lists, the overhead of creating a
 GSSName object on each name and invoking the equal method on each
 name from the Access Control List (ACL) may be prohibitive.  As an
 alternative way of supporting this case, GSS-API defines a special
 form of the contiguous byte array name, which may be compared
 directly (byte by byte).  Contiguous names suitable for comparison
 are generated by the export method.  Exported names may be re-
 imported by using the byte array constructor and specifying the
 NT_EXPORT_NAME as the name type object identifier.  The resulting
 GSSName name will also be a MN.
 The GSSName interface defines public static Oid objects representing
 the standard name types.  Structurally, an exported name object
 consists of a header containing an OID identifying the mechanism that
 authenticated the name, and a trailer containing the name itself,
 where the syntax of the trailer is defined by the individual
 mechanism specification.  Detailed description of the format is
 specified in the language-independent GSS-API specification
 [GSSAPIv2-UPDATE].
 Note that the results obtained by using the equals method will in
 general be different from those obtained by invoking canonicalize and
 export, and then comparing the byte array output.  The first series
 of operation determines whether two (unauthenticated) names identify
 the same principal; the second whether a particular mechanism would
 authenticate them as the same principal.  These two operations will
 in general give the same results only for MNs.
 It is important to note that the above are guidelines as to how
 GSSName implementations should behave, and are not intended to be
 specific requirements of how name objects must be implemented.  The
 mechanism designers are free to decide on the details of their
 implementations of the GSSName interface as long as the behavior
 satisfies the above guidelines.

5.14. Channel Bindings

 GSS-API supports the use of user-specified tags to identify a given
 context to the peer application.  These tags are intended to be used
 to identify the particular communications channel that carries the

Upadhyay & Malkani Standards Track [Page 26] RFC 5653 Java GSS-API Update August 2009

 context.  Channel bindings are communicated to the GSS-API using the
 ChannelBinding object.  The application may use byte arrays to
 specify the application data to be used in the channel binding as
 well as using instances of the InetAddress.  The InetAddress for the
 initiator and/or acceptor can be used within an instance of a
 ChannelBinding.  ChannelBinding can be set for the GSSContext object
 using the setChannelBinding method before the first call to init or
 accept has been performed.  Unless the setChannelBinding method has
 been used to set the ChannelBinding for a GSSContext object, "null"
 ChannelBinding will be assumed.  InetAddress is currently the only
 address type defined within the Java platform and as such, it is the
 only one supported within the ChannelBinding class.  Applications
 that use other types of addresses can include them as part of the
 application-specific data.
 Conceptually, the GSS-API concatenates the initiator and acceptor
 address information, and the application-supplied byte array to form
 an octet-string.  The mechanism calculates a Message Integrity Code
 (MIC) over this octet-string and binds the MIC to the context
 establishment token emitted by the init method of the GSSContext
 interface.  The same bindings are set by the context acceptor for its
 GSSContext object and during processing of the accept method, a MIC
 is calculated in the same way.  The calculated MIC is compared with
 that found in the token, and if the MICs differ, accept will throw a
 GSSException with the major code set to BAD_BINDINGS, and the context
 will not be established.  Some mechanisms may include the actual
 channel binding data in the token (rather than just a MIC);
 applications should therefore not use confidential data as channel-
 binding components.
 Individual mechanisms may impose additional constraints on addresses
 that may appear in channel bindings.  For example, a mechanism may
 verify that the initiator address field of the channel binding
 contains the correct network address of the host system.  Portable
 applications should therefore ensure that they either provide correct
 information for the address fields, or omit the setting of the
 addressing information.

5.15. Stream Objects

 The context object provides overloaded methods that use input and
 output streams as the means to convey authentication and per-message
 GSS-API tokens.  It is important to note that the streams are
 expected to contain the usual GSS-API tokens, which would otherwise
 be handled through the usage of byte arrays.  The tokens are expected
 to have a definite start and an end.  The callers are responsible for

Upadhyay & Malkani Standards Track [Page 27] RFC 5653 Java GSS-API Update August 2009

 ensuring that the supplied streams will not block, or expect to block
 until a full token is processed by the GSS-API method.  Only a single
 GSS-API token will be processed per invocation of the stream-based
 method.
 The usage of streams allows the callers to have control and
 management of the supplied buffers.  Because streams are non-
 primitive objects, the callers can make the streams as complicated or
 as simple as desired simply by using the streams defined in the
 java.io package or creating their own through the use of inheritance.
 This will allow for the application's greatest flexibility.

5.16. Optional Parameters

 Whenever the application wishes to omit an optional parameter the
 "null" value shall be used.  The detailed method descriptions
 indicate which parameters are optional.  Method overloading has also
 been used as a technique to indicate default parameters.

6. Introduction to GSS-API Classes and Interfaces

 This section presents a brief description of the classes and
 interfaces that constitute the GSS-API.  The implementations of these
 are obtained from the CLASSPATH defined by the application.  If Java
 GSS becomes part of the standard Java APIs, then these classes will
 be available by default on all systems as part of the JRE's system
 classes.
 This section also shows the corresponding RFC 2743 [GSSAPIv2-UPDATE]
 functionality implemented by each of the classes.  Detailed
 description of these classes and their methods is presented in
 section 7.

6.1. GSSManager Class

 This abstract class serves as a factory to instantiate
 implementations of the GSS-API interfaces and also provides methods
 to make queries about underlying security mechanisms.
 A default implementation can be obtained using the static method
 getInstance().  Applications that desire to provide their own
 implementation of the GSSManager class can simply extend the abstract
 class themselves.
 This class contains equivalents of the following RFC 2743 [GSSAPIv2-
 UPDATE] routines:

Upadhyay & Malkani Standards Track [Page 28] RFC 5653 Java GSS-API Update August 2009

    RFC 2743 Routine             Function                   Section(s)
    gss_import_name              Create an internal name from  7.1.6-
                                 the supplied information.     7.1.9
    gss_acquire_cred             Acquire credential            7.1.10-
                                 for use.                      7.1.12
    gss_import_sec_context       Create a previously exported  7.1.15
                                 context.
    gss_indicate_mechs           List the mechanisms           7.1.3
                                 supported by this GSS-API
                                 implementation.
    gss_inquire_mechs_for_name   List the mechanisms           7.1.5
                                 supporting the
                                 specified name type.
    gss_inquire_names_for_mech   List the name types           7.1.4
                                 supported by the
                                 specified mechanism.

6.2. GSSName Interface

 GSS-API names are represented in the Java bindings through the
 GSSName interface.  Different name formats and their definitions are
 identified with Universal Object Identifiers (oids).  The format of
 the names can be derived based on the unique oid of each name type.
 The following GSS-API routines are provided by the GSSName interface:
    RFC 2743 Routine        Function                       Section(s)
    gss_display_name        Covert internal name             7.2.7
                            representation to text format.
    gss_compare_name        Compare two internal names.      7.2.3,
                                                             7.2.4
    gss_release_name        Release resources associated     N/A
                            with the internal name.
    gss_canonicalize_name   Convert an internal name to a    7.2.5
                            mechanism name.
    gss_export_name         Convert a mechanism name to      7.2.6
                            export format.

Upadhyay & Malkani Standards Track [Page 29] RFC 5653 Java GSS-API Update August 2009

    gss_duplicate_name      Create a copy of the internal    N/A
                            name.
 The gss_release_name call is not provided as Java does its own
 garbage collection.  The gss_duplicate_name call is also redundant;
 the GSSName interface has no mutator methods that can change the
 state of the object so it is safe for sharing across threads.

6.3. GSSCredential Interface

 The GSSCredential interface is responsible for the encapsulation of
 GSS-API credentials.  Credentials identify a single entity and
 provide the necessary cryptographic information to enable the
 creation of a context on behalf of that entity.  A single credential
 may contain multiple mechanism-specific credentials, each referred to
 as a credential element.  The GSSCredential interface provides the
 functionality of the following GSS-API routines:
    RFC 2743 Routine           Function                    Section(s)
    gss_add_cred               Constructs credentials        7.3.12
                               incrementally.
    gss_inquire_cred           Obtain information about      7.3.4-
                               credential.                   7.3.11
    gss_inquire_cred_by_mech   Obtain per-mechanism          7.3.5-
                               information about             7.3.10
                               a credential.
    gss_release_cred           Dispose of credentials        7.3.3
                               after use.

6.4. GSSContext Interface

 This interface encapsulates the functionality of context-level calls
 required for security context establishment and management between
 peers as well as the per-message services offered to applications.  A
 context is established between a pair of peers and allows the usage
 of security services on a per-message basis on application data.  It
 is created over a single security mechanism.  The GSSContext
 interface provides the functionality of the following GSS-API
 routines:
    RFC 2743 Routine         Function                       Section(s)
    gss_init_sec_context     Initiate the creation of a       7.4.3-
                             security context with a peer.    7.4.6

Upadhyay & Malkani Standards Track [Page 30] RFC 5653 Java GSS-API Update August 2009

    gss_accept_sec_context   Accept a security context        7.4.7-
                             initiated by a peer.             7.4.10
    gss_delete_sec_context   Destroy a security context.      7.4.12
    gss_context_time         Obtain remaining context         7.4.41
                             time.
    gss_inquire_context      Obtain context                   7.4.32-
                             characteristics.                 7.4.46
    gss_wrap_size_limit      Determine token-size limit       7.4.13
                             for gss_wrap.
    gss_export_sec_context   Transfer security context        7.4.22
                             to another process.
    gss_get_mic              Calculate a cryptographic        7.4.18,
                             Message Integrity Code (MIC)     7.4.19
                             for a message.
    gss_verify_mic           Verify integrity on a received   7.4.20,
                             message.                         7.4.21
    gss_wrap                 Attach a MIC to a message and    7.4.14,
                             optionally encrypt the message   7.4.15
                             content.
    gss_unwrap               Obtain a previously wrapped      7.4.16,
                             application message verifying    7.4.17
                             its integrity and optionally
                             decrypting it.
 The functionality offered by the gss_process_context_token routine
 has not been included in the Java bindings specification.  The
 corresponding functionality of gss_delete_sec_context has also been
 modified to not return any peer tokens.  This has been proposed in
 accordance to the recommendations stated in RFC 2743 [GSSAPIv2-
 UPDATE].  GSSContext does offer the functionality of destroying the
 locally stored context information.

6.5. MessageProp Class

 This helper class is used in the per-message operations on the
 context.  An instance of this class is created by the application and
 then passed into the per-message calls.  In some cases, the
 application conveys information to the GSS-API implementation through

Upadhyay & Malkani Standards Track [Page 31] RFC 5653 Java GSS-API Update August 2009

 this object and in other cases the GSS-API returns information to the
 application by setting it in this object.  See the description of the
 per-message operations wrap, unwrap, getMIC, and verifyMIC in the
 GSSContext interfaces for details.

6.6. GSSException Class

 Exceptions are used in the Java bindings to signal fatal errors to
 the calling applications.  This replaces the major and minor codes
 used in the C-bindings specification as a method of signaling
 failures.  The GSSException class handles both minor and major codes,
 as well as their translation into textual representation.  All GSS-
 API methods are declared as throwing this exception.
    RFC 2743 Routine     Function                  Section
    gss_display_status   Retrieve textual          7.8.5, 7.8.6,
                         representation of error   7.8.8, 7.8.9
                         codes.

6.7. Oid Class

 This utility class is used to represent Universal Object Identifiers
 and their associated operations.  GSS-API uses object identifiers to
 distinguish between security mechanisms and name types.  This class,
 aside from being used whenever an object identifier is needed,
 implements the following GSS-API functionality:
    RFC 2743 Routine          Function                         Section
    gss_test_oid_set_member   Determine if the specified oid   7.7.5
                              is part of a set of oids.

6.8. ChannelBinding Class

 An instance of this class is used to specify channel binding
 information to the GSSContext object before the start of a security
 context establishment.  The application may use a byte array to
 specify application data to be used in the channel binding as well as
 to use instances of the InetAddress.  InetAddress is currently the
 only address type defined within the Java platform and as such, it is
 the only one supported within the ChannelBinding class.  Applications
 that use other types of addresses can include them as part of the
 application data.

Upadhyay & Malkani Standards Track [Page 32] RFC 5653 Java GSS-API Update August 2009

7. Detailed GSS-API Class Description

 This section lists a detailed description of all the public methods
 that each of the GSS-API classes and interfaces must provide.

7.1. public abstract class GSSManager

 The GSSManager class is an abstract class that serves as a factory
 for three GSS interfaces: GSSName, GSSCredential, and GSSContext.  It
 also provides methods for applications to determine what mechanisms
 are available from the GSS implementation and what name types these
 mechanisms support.  An instance of the default GSSManager subclass
 may be obtained through the static method getInstance(), but
 applications are free to instantiate other subclasses of GSSManager.
 All but one method in this class are declared abstract.  This means
 that subclasses have to provide the complete implementation for those
 methods.  The only exception to this is the static method
 getInstance(), which will have platform-specific code to return an
 instance of the default subclass.
 Platform providers of GSS are required not to add any constructors to
 this class, private, public, or protected.  This will ensure that all
 subclasses invoke only the default constructor provided to the base
 class by the compiler.
 A subclass extending the GSSManager abstract class may be implemented
 as a modular provider-based layer that utilizes some well-known
 service provider specification.  The GSSManager API provides the
 application with methods to set provider preferences on such an
 implementation.  These methods also allow the implementation to throw
 a well-defined exception in case provider-based configuration is not
 supported.  Applications that expect to be portable should be aware
 of this and recover cleanly by catching the exception.
 It is envisioned that there will be three most common ways in which
 providers will be used:
 1) The application does not care about what provider is used (the
    default case).
 2) The application wants a particular provider to be used
    preferentially, either for a particular mechanism or all the time,
    irrespective of the mechanism.
 3) The application wants to use the locally configured providers as
    far as possible, but if support is missing for one or more
    mechanisms, then it wants to fall back on its own provider.

Upadhyay & Malkani Standards Track [Page 33] RFC 5653 Java GSS-API Update August 2009

 The GSSManager class has two methods that enable these modes of
 usage: addProviderAtFront() and addProviderAtEnd().  These methods
 have the effect of creating an ordered list of <provider, oid> pairs
 where each pair indicates a preference of provider for a given oid.
 The use of these methods does not require any knowledge of whatever
 service provider specification the GSSManager subclass follows.  It
 is hoped that these methods will serve the needs of most
 applications.  Additional methods may be added to an extended
 GSSManager that could be part of a service provider specification
 that is standardized later.

7.1.1. Example Code

    GSSManager mgr = GSSManager.getInstance();
    // What mechs are available to us?
    Oid[] supportedMechs = mgr.getMechs();
    // Set a preference for the provider to be used when support
    // is needed for the mechanisms:
    //  "1.2.840.113554.1.2.2" and "1.3.6.1.5.5.1.1".
    Oid krb = new Oid("1.2.840.113554.1.2.2");
    Oid spkm1 = new Oid("1.3.6.1.5.5.1.1");
    Provider p = (Provider) (new com.foo.security.Provider());
    mgr.addProviderAtFront(p, krb);
    mgr.addProviderAtFront(p, spkm1);
    // What name types does this spkm implementation support?
    Oid[] nameTypes = mgr.getNamesForMech(spkm1);

7.1.2. getInstance

 public static GSSManager getInstance()
 Returns the default GSSManager implementation.

Upadhyay & Malkani Standards Track [Page 34] RFC 5653 Java GSS-API Update August 2009

7.1.3. getMechs

 public abstract Oid[] getMechs()
 Returns an array of Oid objects indicating the mechanisms available
 to GSS-API callers.  A "null" value is returned when no mechanism are
 available (an example of this would be when mechanism are dynamically
 configured, and currently no mechanisms are installed).

7.1.4. getNamesForMech

 public abstract Oid[] getNamesForMech(Oid mech)
                       throws GSSException
 Returns name type Oid's supported by the specified mechanism.
 Parameters:
    mech:         The Oid object for the mechanism to query.

7.1.5. getMechsForName

 public abstract Oid[] getMechsForName(Oid nameType)
 Returns an array of Oid objects corresponding to the mechanisms that
 support the specific name type. "null" is returned when no mechanisms
 are found to support the specified name type.
 Parameters:
    nameType:     The Oid object for the name type.

7.1.6. createName

 public abstract GSSName createName(String nameStr, Oid nameType)
                 throws GSSException
 Factory method to convert a contiguous string name from the specified
 namespace to a GSSName object.  In general, the GSSName object
 created will not be an MN; two examples that are exceptions to this
 are when the namespace type parameter indicates NT_EXPORT_NAME or
 when the GSS-API implementation is not multi-mechanism.
 Parameters:
    nameStr:      The string representing a printable form of the name
                  to create.

Upadhyay & Malkani Standards Track [Page 35] RFC 5653 Java GSS-API Update August 2009

    nameType:     The Oid specifying the namespace of the printable
                  name is supplied.  Note that nameType serves to
                  describe and qualify the interpretation of the input
                  nameStr, it does not necessarily imply a type for
                  the output GSSName implementation.  The "null" value
                  can be used to specify that a mechanism-specific
                  default printable syntax should be assumed by each
                  mechanism that examines nameStr.

7.1.7. createName

 public abstract GSSName createName(byte[] name, Oid nameType)
                 throws GSSException
 Factory method to convert a contiguous byte array containing a name
 from the specified namespace to a GSSName object.  In general, the
 GSSName object created will not be an MN; two examples that are
 exceptions to this are when the namespace type parameter indicates
 NT_EXPORT_NAME or when the GSS-API implementation is not multi-
 mechanism.
 Parameters:
    name:         The byte array containing the name to create.
    nameType:     The Oid specifying the namespace of the name
                  supplied in the byte array.  Note that nameType
                  serves to describe and qualify the interpretation of
                  the input name byte array; it does not necessarily
                  imply a type for the output GSSName implementation.
                  The "null" value can be used to specify that a
                  mechanism-specific default syntax should be assumed
                  by each mechanism that examines the byte array.

7.1.8. createName

 public abstract GSSName createName(String nameStr, Oid nameType,
                 Oid mech) throws GSSException
 Factory method to convert a contiguous string name from the specified
 namespace to a GSSName object that is a mechanism name (MN).  In
 other words, this method is a utility that does the equivalent of two
 steps: the createName described in section 7.1.6, and then also the
 GSSName.canonicalize() described in section 7.2.5.

Upadhyay & Malkani Standards Track [Page 36] RFC 5653 Java GSS-API Update August 2009

 Parameters:
    nameStr:      The string representing a printable form of the name
                  to create.
    nameType:     The Oid specifying the namespace of the printable
                  name supplied.  Note that nameType serves to
                  describe and qualify the interpretation of the input
                  nameStr; it does not necessarily imply a type for
                  the output GSSName implementation.  The "null" value
                  can be used to specify that a mechanism-specific
                  default printable syntax should be assumed when the
                  mechanism examines nameStr.
    mech:         Oid specifying the mechanism for which this name
                  should be created.

7.1.9. createName

 public abstract GSSName createName(byte[] name, Oid nameType,
                 Oid mech) throws GSSException
 Factory method to convert a contiguous byte array containing a name
 from the specified namespace to a GSSName object that is an MN.  In
 other words, this method is a utility that does the equivalent of two
 steps: the createName described in section 7.1.7, and then also the
 GSSName.canonicalize() described in section 7.2.5.
 Parameters:
    name:         The byte array representing the name to create.
    nameType:     The Oid specifying the namespace of the name
                  supplied in the byte array.  Note that nameType
                  serves to describe and qualify the interpretation of
                  the input name byte array, it does not necessarily
                  imply a type for the output GSSName implementation.
                  The "null" value can be used to specify that a
                  mechanism-specific default syntax should be assumed
                  by each mechanism that examines the byte array.
    mech:         Oid specifying the mechanism for which this name
                  should be created.

Upadhyay & Malkani Standards Track [Page 37] RFC 5653 Java GSS-API Update August 2009

7.1.10. createCredential

 public abstract GSSCredential createCredential(int usage)
                 throws GSSException
 Factory method for acquiring default credentials.  This will cause
 the GSS-API to use system-specific defaults for the set of
 mechanisms, name, and a DEFAULT lifetime.
 Parameters:
    usage:        The intended usage for this credential object.  The
                  value of this parameter must be one of:
                  GSSCredential.INITIATE_AND_ACCEPT(0),
                  GSSCredential.INITIATE_ONLY(1), or
                  GSSCredential.ACCEPT_ONLY(2)

7.1.11. createCredential

 public abstract GSSCredential createCredential(GSSName aName,
                 int lifetime, Oid mech, int usage)
                 throws GSSException
 Factory method for acquiring a single mechanism credential.
 Parameters:
    aName:        Name of the principal for whom this credential is to
                  be acquired.  Use "null" to specify the default
                  principal.
    lifetime:     The number of seconds that credentials should remain
                  valid.  Use GSSCredential.INDEFINITE_LIFETIME to
                  request that the credentials have the maximum
                  permitted lifetime.  Use
                  GSSCredential.DEFAULT_LIFETIME to request default
                  credential lifetime.
    mech:         The oid of the desired mechanism.  Use "(Oid) null"
                  to request the default mechanism(s).

Upadhyay & Malkani Standards Track [Page 38] RFC 5653 Java GSS-API Update August 2009

    usage:        The intended usage for this credential object.  The
                  value of this parameter must be one of:
                  GSSCredential.INITIATE_AND_ACCEPT(0),
                  GSSCredential.INITIATE_ONLY(1), or
                  GSSCredential.ACCEPT_ONLY(2)

7.1.12. createCredential

 public abstract GSSCredential createCredential(GSSName aName,
                 int lifetime, Oid[] mechs, int usage)
                 throws GSSException
 Factory method for acquiring credentials over a set of mechanisms.
 Acquires credentials for each of the mechanisms specified in the
 array called mechs.  To determine the list of mechanisms' for which
 the acquisition of credentials succeeded, the caller should use the
 GSSCredential.getMechs() method.
 Parameters:
    aName:        Name of the principal for whom this credential is to
                  be acquired.  Use "null" to specify the default
                  principal.
    lifetime:     The number of seconds that credentials should remain
                  valid.  Use GSSCredential.INDEFINITE_LIFETIME to
                  request that the credentials have the maximum
                  permitted lifetime.  Use
                  GSSCredential.DEFAULT_LIFETIME to request default
                  credential lifetime.
    mechs:        The array of mechanisms over which the credential is
                  to be acquired.  Use "(Oid[]) null" for requesting a
                  system-specific default set of mechanisms.
    usage:        The intended usage for this credential object.  The
                  value of this parameter must be one of:
                  GSSCredential.INITIATE_AND_ACCEPT(0),
                  GSSCredential.INITIATE_ONLY(1), or
                  GSSCredential.ACCEPT_ONLY(2)

7.1.13. createContext

 public abstract GSSContext createContext(GSSName peer, Oid mech,
                 GSSCredential myCred, int lifetime)
                 throws GSSException

Upadhyay & Malkani Standards Track [Page 39] RFC 5653 Java GSS-API Update August 2009

 Factory method for creating a context on the initiator's side.
 Context flags may be modified through the mutator methods prior to
 calling GSSContext.initSecContext().
 Parameters:
    peer:         Name of the target peer.
    mech:         Oid of the desired mechanism.  Use "(Oid) null" to
                  request the default mechanism.
    myCred:       Credentials of the initiator.  Use "null" to act as
                  a default initiator principal.
    lifetime:     The request lifetime, in seconds, for the context.
                  Use GSSContext.INDEFINITE_LIFETIME and
                  GSSContext.DEFAULT_LIFETIME to request indefinite or
                  default context lifetime.

7.1.14. createContext

 public abstract GSSContext createContext(GSSCredential myCred)
                 throws GSSException
 Factory method for creating a context on the acceptor' side.  The
 context's properties will be determined from the input token supplied
 to the accept method.
 Parameters:
    myCred:       Credentials for the acceptor.  Use "null" to act as
                  a default acceptor principal.

7.1.15. createContext

 public abstract GSSContext createContext(byte[] interProcessToken)
                 throws GSSException
 Factory method for creating a previously exported context.  The
 context properties will be determined from the input token and can't
 be modified through the set methods.
 Parameters:
    interProcessToken: The token previously emitted from the export
                       method.

Upadhyay & Malkani Standards Track [Page 40] RFC 5653 Java GSS-API Update August 2009

7.1.16. addProviderAtFront

 public abstract void addProviderAtFront(Provider p, Oid mech)
                 throws GSSException
 This method is used to indicate to the GSSManager that the
 application would like a particular provider to be used ahead of all
 others when support is desired for the given mechanism.  When a value
 of "null" is used instead of an Oid for the mechanism, the GSSManager
 must use the indicated provider ahead of all others no matter what
 the mechanism is.  Only when the indicated provider does not support
 the needed mechanism should the GSSManager move on to a different
 provider.
 Calling this method repeatedly preserves the older settings but
 lowers them in preference thus forming an ordered list of provider
 and Oid pairs that grows at the top.
 Calling addProviderAtFront with a null Oid will remove all previous
 preferences that were set for this provider in the GSSManager
 instance.  Calling addProviderAtFront with a non-null Oid will remove
 any previous preference that was set using this mechanism and this
 provider together.
 If the GSSManager implementation does not support an SPI with a
 pluggable provider architecture, it should throw a GSSException with
 the status code GSSException.UNAVAILABLE to indicate that the
 operation is unavailable.
 Parameters:
    p:            The provider instance that should be used whenever
                  support is needed for mech.
    mech:         The mechanism for which the provider is being set.

7.1.17. Example Code

 Suppose an application desired that the provider A always be checked
 first when any mechanism is needed, it would call:
    GSSManager mgr = GSSManager.getInstance();
    // mgr may at this point have its own pre-configured list
    // of provider preferences.  The following will prepend to
    // any such list:
    mgr.addProviderAtFront(A, null);

Upadhyay & Malkani Standards Track [Page 41] RFC 5653 Java GSS-API Update August 2009

 Now if it also desired that the mechanism of Oid m1 always be
 obtained from the provider B before the previously set A was checked,
 it would call:
    mgr.addProviderAtFront(B, m1);
 The GSSManager would then first check with B if m1 was needed.  In
 case B did not provide support for m1, the GSSManager would continue
 on to check with A.  If any mechanism m2 is needed where m2 is
 different from m1, then the GSSManager would skip B and check with A
 directly.
 Suppose, at a later time, the following call is made to the same
 GSSManager instance:
    mgr.addProviderAtFront(B, null)
 then the previous setting with the pair (B, m1) is subsumed by this
 and should be removed.  Effectively, the list of preferences now
 becomes {(B, null), (A, null), ... //followed by the pre-configured
 list.
 Please note, however, that the following call:
    mgr.addProviderAtFront(A, m3)
 does not subsume the previous setting of (A, null), and the list will
 effectively become {(A, m3), (B, null), (A, null), ...}

7.1.18. addProviderAtEnd

 public abstract void addProviderAtEnd(Provider p, Oid mech)
                 throws GSSException
 This method is used to indicate to the GSSManager that the
 application would like a particular provider to be used if no other
 provider can be found that supports the given mechanism.  When a
 value of "null" is used instead of an Oid for the mechanism, the
 GSSManager must use the indicated provider for any mechanism.
 Calling this method repeatedly preserves the older settings, but
 raises them above newer ones in preference thus forming an ordered
 list of providers and Oid pairs that grows at the bottom.  Thus, the
 older provider settings will be utilized first before this one is.
 If there are any previously existing preferences that conflict with
 the preference being set here, then the GSSManager should ignore this
 request.

Upadhyay & Malkani Standards Track [Page 42] RFC 5653 Java GSS-API Update August 2009

 If the GSSManager implementation does not support an SPI with a
 pluggable provider architecture, it should throw a GSSException with
 the status code GSSException.UNAVAILABLE to indicate that the
 operation is unavailable.
 Parameters:
    p:            The provider instance that should be used whenever
                  support is needed for mech.
    mech:         The mechanism for which the provider is being set.

7.1.19. Example Code

 Suppose an application desired that when a mechanism of Oid m1 is
 needed, the system default providers always be checked first, and
 only when they do not support m1 should a provider A be checked.  It
 would then make the call:
    GSSManager mgr = GSSManager.getInstance();
    mgr.addProviderAtEnd(A, m1);
 Now, if it also desired that for all mechanisms the provider B be
 checked after all configured providers have been checked, it would
 then call:
    mgr.addProviderAtEnd(B, null);
 Effectively, the list of preferences now becomes {..., (A, m1), (B,
 null)}.
 Suppose, at a later time, the following call is made to the same
 GSSManager instance:
    mgr.addProviderAtEnd(B, m2)
 then the previous setting with the pair (B, null) subsumes this;
 therefore, this request should be ignored.  The same would happen if
 a request is made for the already existing pairs of (A, m1) or (B,
 null).
 Please note, however, that the following call:
    mgr.addProviderAtEnd(A, null)
 is not subsumed by the previous setting of (A, m1) and the list will
 effectively become {..., (A, m1), (B, null), (A, null)}.

Upadhyay & Malkani Standards Track [Page 43] RFC 5653 Java GSS-API Update August 2009

7.2. public interface GSSName

 This interface encapsulates a single GSS-API principal entity.
 Different name formats and their definitions are identified with
 Universal Object Identifiers (Oids).  The format of the names can be
 derived based on the unique oid of its namespace type.

7.2.1. Example Code

 Included below are code examples utilizing the GSSName interface.
 The code below creates a GSSName, converts it to a mechanism name
 (MN), performs a comparison, obtains a printable representation of
 the name, exports it and then re-imports to obtain a new GSSName.
    GSSManager mgr = GSSManager.getInstance();
    // create a host-based service name
    GSSName name = mgr.createName("service@host",
                    GSSName.NT_HOSTBASED_SERVICE);
    Oid krb5 = new Oid("1.2.840.113554.1.2.2");
    GSSName mechName = name.canonicalize(krb5);
    // the above two steps are equivalent to the following
    GSSName mechName = mgr.createName("service@host",
                    GSSName.NT_HOSTBASED_SERVICE, krb5);
    // perform name comparison
    if (name.equals(mechName))
            print("Names are equals.");
    // obtain textual representation of name and its printable
    // name type
    print(mechName.toString() +
          mechName.getStringNameType().toString());
    // export and re-import the name
    byte[] exportName = mechName.export();
    // create a new name object from the exported buffer
    GSSName newName = mgr.createName(exportName,
                      GSSName.NT_EXPORT_NAME);

Upadhyay & Malkani Standards Track [Page 44] RFC 5653 Java GSS-API Update August 2009

7.2.2. Static Constants

 public static final Oid NT_HOSTBASED_SERVICE
 Oid indicating a host-based service name form.  It is used to
 represent services associated with host computers.  This name form is
 constructed using two elements, "service" and "hostname", as follows:
    service@hostname
 Values for the "service" element are registered with the IANA.  It
 represents the following value: { iso(1) member-body(2) Unites
 States(840) mit(113554) infosys(1) gssapi(2) generic(1)
 service_name(4) }
 public static final Oid NT_USER_NAME
 Name type to indicate a named user on a local system.  It represents
 the following value: { iso(1) member-body(2) United States(840)
 mit(113554) infosys(1) gssapi(2) generic(1) user_name(1) }
 public static final Oid NT_MACHINE_UID_NAME
 Name type to indicate a numeric user identifier corresponding to a
 user on a local system (e.g., Uid).  It represents the following
 value: { iso(1) member-body(2) United States(840) mit(113554)
 infosys(1) gssapi(2) generic(1) machine_uid_name(2) }
 public static final Oid NT_STRING_UID_NAME
 Name type to indicate a string of digits representing the numeric
 user identifier of a user on a local system.  It represents the
 following value: { iso(1) member-body(2) United States(840)
 mit(113554) infosys(1) gssapi(2) generic(1) string_uid_name(3) }
 public static final Oid NT_ANONYMOUS
 Name type for representing an anonymous entity.  It represents the
 following value: { iso(1), org(3), dod(6), internet(1), security(5),
 nametypes(6), gss-anonymous-name(3) }
 public static final Oid NT_EXPORT_NAME
 Name type used to indicate an exported name produced by the export
 method.  It represents the following value: { iso(1), org(3), dod(6),
 internet(1), security(5), nametypes(6), gss-api-exported-name(4) }

Upadhyay & Malkani Standards Track [Page 45] RFC 5653 Java GSS-API Update August 2009

7.2.3. equals

 public boolean equals(GSSName another) throws GSSException
 Compares two GSSName objects to determine whether they refer to the
 same entity.  This method may throw a GSSException when the names
 cannot be compared.  If either of the names represents an anonymous
 entity, the method will return "false".
 Parameters:
    another:      GSSName object with which to compare.

7.2.4. equals

    public boolean equals(Object another)
    A variation of the equals method, described in section 7.2.3, that
    is provided to override the Object.equals() method that the
    implementing class will inherit.  The behavior is exactly the same
    as that in section 7.2.3 except that no GSSException is thrown;
    instead, "false" will be returned in the situation where an error
    occurs.  (Note that the Java language specification requires that
    two objects that are equal according to the equals(Object) method
    must return the same integer result when the hashCode() method is
    called on them.)
    Parameters:
    another:      GSSName object with which to compare.

7.2.5. canonicalize

    public GSSName canonicalize(Oid mech) throws GSSException
    Creates a mechanism name (MN) from an arbitrary internal name.
    This is equivalent to using the factory methods described in
    sections 7.1.8 or 7.1.9 that take the mechanism name as one of
    their parameters.
    Parameters:
    mech:         The oid for the mechanism for which the canonical
                  form of the name is requested.

Upadhyay & Malkani Standards Track [Page 46] RFC 5653 Java GSS-API Update August 2009

7.2.6. export

 public byte[] export() throws GSSException
 Returns a canonical contiguous byte representation of a mechanism
 name (MN), suitable for direct, byte-by-byte comparison by
 authorization functions.  If the name is not an MN, implementations
 may throw a GSSException with the NAME_NOT_MN status code.  If an
 implementation chooses not to throw an exception, it should use some
 system-specific default mechanism to canonicalize the name and then
 export it.  The format of the header of the output buffer is
 specified in RFC 2743 [GSSAPIv2-UPDATE].

7.2.7. toString

 public String toString()
 Returns a textual representation of the GSSName object.  To retrieve
 the printed name format, which determines the syntax of the returned
 string, the getStringNameType method can be used.

7.2.8. getStringNameType

 public Oid getStringNameType() throws GSSException
 Returns the oid representing the type of name returned through the
 toString method.  Using this oid, the syntax of the printable name
 can be determined.

7.2.9. isAnonymous

 public boolean isAnonymous()
 Tests if this name object represents an anonymous entity.  Returns
 "true" if this is an anonymous name.

7.2.10. isMN

 public boolean isMN()
 Tests if this name object contains only one mechanism element and is
 thus a mechanism name as defined by RFC 2743 [GSSAPIv2-UPDATE].

7.3. public interface GSSCredential implements Cloneable

 This interface encapsulates the GSS-API credentials for an entity.  A
 credential contains all the necessary cryptographic information to
 enable the creation of a context on behalf of the entity that it

Upadhyay & Malkani Standards Track [Page 47] RFC 5653 Java GSS-API Update August 2009

 represents.  It may contain multiple, distinct, mechanism-specific
 credential elements, each containing information for a specific
 security mechanism, but all referring to the same entity.
 A credential may be used to perform context initiation, acceptance,
 or both.
 GSS-API implementations must impose a local access-control policy on
 callers to prevent unauthorized callers from acquiring credentials to
 which they are not entitled.  GSS-API credential creation is not
 intended to provide a "login to the network" function, as such a
 function would involve the creation of new credentials rather than
 merely acquiring a handle to existing credentials.  Such functions,
 if required, should be defined in implementation-specific extensions
 to the API.
 If credential acquisition is time-consuming for a mechanism, the
 mechanism may choose to delay the actual acquisition until the
 credential is required (e.g., by GSSContext).  Such mechanism-
 specific implementation decisions should be invisible to the calling
 application; thus, the query methods immediately following the
 creation of a credential object must return valid credential data,
 and may therefore incur the overhead of a deferred credential
 acquisition.
 Applications will create a credential object passing the desired
 parameters.  The application can then use the query methods to obtain
 specific information about the instantiated credential object
 (equivalent to the gss_inquire routines).  When the credential is no
 longer needed, the application should call the dispose (equivalent to
 gss_release_cred) method to release any resources held by the
 credential object and to destroy any cryptographically sensitive
 information.
 Classes implementing this interface also implement the Cloneable
 interface.  This indicates that the class will support the clone()
 method that will allow the creation of duplicate credentials.  This
 is useful when called just before the add() call to retain a copy of
 the original credential.

Upadhyay & Malkani Standards Track [Page 48] RFC 5653 Java GSS-API Update August 2009

7.3.1. Example Code

 This example code demonstrates the creation of a GSSCredential
 implementation for a specific entity, querying of its fields, and its
 release when it is no longer needed.
    GSSManager mgr = GSSManager.getInstance();
    // start by creating a name object for the entity
    GSSName name = mgr.createName("userName", GSSName.NT_USER_NAME);
    // now acquire credentials for the entity
    GSSCredential cred = mgr.createCredential(name,
                         GSSCredential.ACCEPT_ONLY);
    // display credential information - name, remaining lifetime,
    // and the mechanisms it has been acquired over
    print(cred.getName().toString());
    print(cred.getRemainingLifetime());
    Oid[] mechs = cred.getMechs();
    if (mechs != null) {
       for (int i = 0; i < mechs.length; i++)
           print(mechs[i].toString());
    }
    // release system resources held by the credential
    cred.dispose();

7.3.2. Static Constants

 public static final int INITIATE_AND_ACCEPT
 Credential usage flag requesting that it be able to be used for both
 context initiation and acceptance.  The value of this constant is 0.
 public static final int INITIATE_ONLY
 Credential usage flag requesting that it be able to be used for
 context initiation only.  The value of this constant is 1.
 public static final int ACCEPT_ONLY
 Credential usage flag requesting that it be able to be used for
 context acceptance only.  The value of this constant is 2.
 public static final int DEFAULT_LIFETIME
 A lifetime constant representing the default credential lifetime.

Upadhyay & Malkani Standards Track [Page 49] RFC 5653 Java GSS-API Update August 2009

 The value of this constant is 0.
 public static final int INDEFINITE_LIFETIME
 A lifetime constant representing indefinite credential lifetime.  The
 value of this constant is the maximum integer value in Java -
 Integer.MAX_VALUE.

7.3.3. dispose

 public void dispose() throws GSSException
 Releases any sensitive information that the GSSCredential object may
 be containing.  Applications should call this method as soon as the
 credential is no longer needed to minimize the time any sensitive
 information is maintained.

7.3.4. getName

 public GSSName getName() throws GSSException
 Retrieves the name of the entity that the credential asserts.

7.3.5. getName

 public GSSName getName(Oid mechOID) throws GSSException
 Retrieves a mechanism name of the entity that the credential asserts.
 Equivalent to calling canonicalize() on the name returned by section
 7.3.4.
 Parameters:
    mechOID:      The mechanism for which information should be
                  returned.

7.3.6. getRemainingLifetime

 public int getRemainingLifetime() throws GSSException
 Returns the remaining lifetime in seconds for a credential.  The
 remaining lifetime is the minimum lifetime for any of the underlying
 credential mechanisms.  A return value of
 GSSCredential.INDEFINITE_LIFETIME indicates that the credential does
 not expire.  A return value of 0 indicates that the credential is
 already expired.

Upadhyay & Malkani Standards Track [Page 50] RFC 5653 Java GSS-API Update August 2009

7.3.7. getRemainingInitLifetime

 public int getRemainingInitLifetime(Oid mech) throws GSSException
 Returns the remaining lifetime in seconds for the credential to
 remain capable of initiating security contexts under the specified
 mechanism.  A return value of GSSCredential.INDEFINITE_LIFETIME
 indicates that the credential does not expire for context initiation.
 A return value of 0 indicates that the credential is already expired.
 Parameters:
    mechOID:      The mechanism for which information should be
                  returned.

7.3.8. getRemainingAcceptLifetime

 public int getRemainingAcceptLifetime(Oid mech) throws GSSException
 Returns the remaining lifetime in seconds for the credential to
 remain capable of accepting security contexts under the specified
 mechanism.  A return value of GSSCredential.INDEFINITE_LIFETIME
 indicates that the credential does not expire for context acceptance.
 A return value of 0 indicates that the credential is already expired.
 Parameters:
    mechOID:      The mechanism for which information should be
                  returned.

7.3.9. getUsage

 public int getUsage() throws GSSException
 Returns the credential usage flag as a union over all mechanisms.
 The return value will be one of GSSCredential.INITIATE_AND_ACCEPT(0),
 GSSCredential.INITIATE_ONLY(1), or GSSCredential.ACCEPT_ONLY(2).

7.3.10. getUsage

 public int getUsage(Oid mechOID) throws GSSException
 Returns the credential usage flag for the specified mechanism only.
 The return value will be one of GSSCredential.INITIATE_AND_ACCEPT(0),
 GSSCredential.INITIATE_ONLY(1), or GSSCredential.ACCEPT_ONLY(2).

Upadhyay & Malkani Standards Track [Page 51] RFC 5653 Java GSS-API Update August 2009

 Parameters:
    mechOID:      The mechanism for which information should be
                  returned.

7.3.11. getMechs

 public Oid[] getMechs() throws GSSException
 Returns an array of mechanisms supported by this credential.

7.3.12. add

 public void add(GSSName aName, int initLifetime, int acceptLifetime,
                 Oid mech, int usage) throws GSSException
 Adds a mechanism-specific credential-element to an existing
 credential.  This method allows the construction of credentials one
 mechanism at a time.
 This routine is envisioned to be used mainly by context acceptors
 during the creation of acceptance credentials, which are to be used
 with a variety of clients using different security mechanisms.
 This routine adds the new credential element "in-place".  To add the
 element in a new credential, first call clone() to obtain a copy of
 this credential, then call its add() method.
 Parameters:
    aName:             Name of the principal for whom this credential
                       is to be acquired.  Use "null" to specify the
                       default principal.
    initLifetime:      The number of seconds that credentials should
                       remain valid for initiating of security
                       contexts.  Use
                       GSSCredential.INDEFINITE_LIFETIME to request
                       that the credentials have the maximum permitted
                       lifetime.  Use GSSCredential.DEFAULT_LIFETIME
                       to request default credential lifetime.
    acceptLifetime:    The number of seconds that credentials should
                       remain valid for accepting of security
                       contexts.

Upadhyay & Malkani Standards Track [Page 52] RFC 5653 Java GSS-API Update August 2009

                       Use GSSCredential.INDEFINITE_LIFETIME to
                       request that the credentials have the maximum
                       permitted lifetime.  Use
                       GSSCredential.DEFAULT_LIFETIME to request
                       default credential lifetime.
    mech:              The mechanisms over which the credential is to
                       be acquired.
    usage:             The intended usage for this credential object.
                       The value of this parameter must be one of:
                       GSSCredential.INITIATE_AND_ACCEPT(0),
                       GSSCredential.INITIATE_ONLY(1), or
                       GSSCredential.ACCEPT_ONLY(2)

7.3.13. equals

 public boolean equals(Object another)
 Tests if this GSSCredential refers to the same entity as the supplied
 object.  The two credentials must be acquired over the same
 mechanisms and must refer to the same principal.  Returns "true" if
 the two GSSCredentials refer to the same entity; "false" otherwise.
 (Note that the Java language specification [JLS] requires that two
 objects that are equal according to the equals(Object) method must
 return the same integer result when the hashCode() method is called
 on them.)
 Parameters:
    another:      Another GSSCredential object for comparison.

7.4. public interface GSSContext

 This interface encapsulates the GSS-API security context and provides
 the security services (wrap, unwrap, getMIC, verifyMIC) that are
 available over the context.  Security contexts are established
 between peers using locally acquired credentials.  Multiple contexts
 may exist simultaneously between a pair of peers, using the same or
 different set of credentials.  GSS-API functions in a manner
 independent of the underlying transport protocol and depends on its
 calling application to transport its tokens between peers.

Upadhyay & Malkani Standards Track [Page 53] RFC 5653 Java GSS-API Update August 2009

 Before the context establishment phase is initiated, the context
 initiator may request specific characteristics desired of the
 established context.  These can be set using the set methods.  After
 the context is established, the caller can check the actual
 characteristic and services offered by the context using the query
 methods.
 The context establishment phase begins with the first call to the
 init method by the context initiator.  During this phase, the
 initSecContext and acceptSecContext methods will produce GSS-API
 authentication tokens, which the calling application needs to send to
 its peer.  If an error occurs at any point, an exception will get
 thrown and the code will start executing in a catch block.  If not,
 the normal flow of code continues and the application can make a call
 to the isEstablished() method.  If this method returns "false" it
 indicates that a token is needed from its peer in order to continue
 the context establishment phase.  A return value of "true" signals
 that the local end of the context is established.  This may still
 require that a token be sent to the peer, if one is produced by GSS-
 API.  During the context establishment phase, the isProtReady()
 method may be called to determine if the context can be used for the
 per-message operations.  This allows applications to use per-message
 operations on contexts that aren't fully established.
 After the context has been established or the isProtReady() method
 returns "true", the query routines can be invoked to determine the
 actual characteristics and services of the established context.  The
 application can also start using the per-message methods of wrap and
 getMIC to obtain cryptographic operations on application supplied
 data.
 When the context is no longer needed, the application should call
 dispose to release any system resources the context may be using.

7.4.1. Example Code

 The example code presented below demonstrates the usage of the
 GSSContext interface for the initiating peer.  Different operations
 on the GSSContext object are presented, including: object
 instantiation, setting of desired flags, context establishment, query
 of actual context flags, per-message operations on application data,
 and finally context deletion.
    GSSManager mgr = GSSManager.getInstance();
    // start by creating the name for a service entity
    GSSName targetName = mgr.createName("service@host",
                         GSSName.NT_HOSTBASED_SERVICE);

Upadhyay & Malkani Standards Track [Page 54] RFC 5653 Java GSS-API Update August 2009

    // create a context using default credentials for the above entity
    // and the implementation-specific default mechanism
    GSSContext context = mgr.createContext(targetName,
                    null,   /* default mechanism */
                    null,   /* default credentials */
                    GSSContext.INDEFINITE_LIFETIME);
    // set desired context options - all others are "false" by default
    context.requestConf(true);
    context.requestMutualAuth(true);
    context.requestReplayDet(true);
    context.requestSequenceDet(true);
    // establish a context between peers - using byte arrays
    byte[]inTok = new byte[0];
    try {
        do {
            byte[] outTok = context.initSecContext(inTok, 0,
                                                  inTok.length);
            // send the token if present
            if (outTok != null)
                sendToken(outTok);
            // check if we should expect more tokens
            if (context.isEstablished())
                break;
            // another token expected from peer
            inTok = readToken();
        } while (true);
    } catch (GSSException e) {
        print("GSSAPI error: " + e.getMessage());
    }
    // display context information
    print("Remaining lifetime in seconds = " + context.getLifetime());
    print("Context mechanism = " + context.getMech().toString());
    print("Initiator = " + context.getSrcName().toString());
    print("Acceptor = " + context.getTargName().toString());
    if (context.getConfState())
        print("Confidentiality security service available");
    if (context.getIntegState())

Upadhyay & Malkani Standards Track [Page 55] RFC 5653 Java GSS-API Update August 2009

        print("Integrity security service available");
    // perform wrap on an application-supplied message, appMsg,
    // using QOP = 0, and requesting privacy service
    byte[] appMsg ...
    MessageProp mProp = new MessageProp(0, true);
    byte[] tok = context.wrap(appMsg, 0, appMsg.length, mProp);
    if (mProp.getPrivacy())
        print("Message protected with privacy.");
    sendToken(tok);
    // release the local end of the context
    context.dispose();

7.4.2. Static Constants

 public static final int DEFAULT_LIFETIME
 A lifetime constant representing the default context lifetime.  The
 value of this constant is 0.
 public static final int INDEFINITE_LIFETIME
 A lifetime constant representing indefinite context lifetime.  The
 value of this constant is the maximum integer value in Java -
 Integer.MAX_VALUE.

7.4.3. initSecContext

 public byte[] initSecContext(byte[] inputBuf, int offset, int len)
               throws GSSException
 Called by the context initiator to start the context creation
 process.  This is equivalent to the stream-based method except that
 the token buffers are handled as byte arrays instead of using stream
 objects.  This method may return an output token that the application
 will need to send to the peer for processing by the accept call.
 Typically, the application would do so by calling the flush() method
 on an OutputStream that encapsulates the connection between the two
 peers.  The application can call isEstablished() to determine if the
 context establishment phase is complete for this peer.  A return
 value of "false" from isEstablished() indicates that more tokens are
 expected to be supplied to the initSecContext() method.  Note that it
 is possible that the initSecContext() method will return a token for

Upadhyay & Malkani Standards Track [Page 56] RFC 5653 Java GSS-API Update August 2009

 the peer and isEstablished() will return "true" also.  This indicates
 that the token needs to be sent to the peer, but the local end of the
 context is now fully established.
 Upon completion of the context establishment, the available context
 options may be queried through the get methods.
 Parameters:
    inputBuf:     Token generated by the peer.  This parameter is
                  ignored on the first call.
    offset:       The offset within the inputBuf where the token
                  begins.
    len:          The length of the token within the inputBuf
                  (starting at the offset).

7.4.4. Example Code

    // Create a new GSSContext implementation object.
    // GSSContext wrapper implements interface GSSContext.
    GSSContext context = mgr.createContext(...);
    byte[] inTok = new byte[0];
    try {
        do {
            byte[] outTok = context.initSecContext(inTok, 0,
                            inTok.length);
            // send the token if present
            if (outTok != null)
                sendToken(outTok);
            // check if we should expect more tokens
            if (context.isEstablished())
                break;
            // another token expected from peer
            inTok = readToken();
        } while (true);
    } catch (GSSException e) {
       print("GSSAPI error: " + e.getMessage());
    }

Upadhyay & Malkani Standards Track [Page 57] RFC 5653 Java GSS-API Update August 2009

7.4.5. initSecContext

 public int initSecContext(InputStream inStream,
            OutputStream outStream) throws GSSException
 Called by the context initiator to start the context creation
 process.  This is equivalent to the byte-array-based method.  This
 method may write an output token to the outStream, which the
 application will need to send to the peer for processing by the
 accept call.  Typically, the application would do so by calling the
 flush() method on an OutputStream that encapsulates the connection
 between the two peers.  The application can call isEstablished() to
 determine if the context establishment phase is complete for this
 peer.  A return value of "false" from isEstablished indicates that
 more tokens are expected to be supplied to the initSecContext method.
 Note that it is possible that the initSecContext() method will return
 a token for the peer and isEstablished() will return "true" also.
 This indicates that the token needs to be sent to the peer, but the
 local end of the context is now fully established.
 The GSS-API authentication tokens contain a definitive start and end.
 This method will attempt to read one of these tokens per invocation,
 and may block on the stream if only part of the token is available.
 Upon completion of the context establishment, the available context
 options may be queried through the get methods.
 Parameters:
    inStream:     Contains the token generated by the peer.  This
                  parameter is ignored on the first call.
    outStream:    Output stream where the output token will be
                  written.  During the final stage of context
                  establishment, there may be no bytes written.

7.4.6. Example Code

 This sample code merely demonstrates the token exchange during the
 context establishment phase.  It is expected that most Java
 applications will use custom implementations of the Input and Output
 streams that encapsulate the communication routines.  For instance, a
 simple read on the application InputStream, when called by the
 Context, might cause a token to be read from the peer, and a simple
 flush() on the application OutputStream might cause a previously
 written token to be transmitted to the peer.

Upadhyay & Malkani Standards Track [Page 58] RFC 5653 Java GSS-API Update August 2009

    // Create a new GSSContext implementation object.
    // GSSContext wrapper implements interface GSSContext.
    GSSContext context = mgr.createContext(...);
    // use standard java.io stream objects
    ByteArrayOutputStream os = new ByteArrayOutputStream();
    ByteArrayInputStream is = null;
    try {
        do {
            context.initSecContext(is, os);
            // send token if present
            if (os.size() > 0)
                sendToken(os);
            // check if we should expect more tokens
            if (context.isEstablished())
                break;
            // another token expected from peer
            is = recvToken();
        } while (true);
    } catch (GSSException e) {
        print("GSSAPI error: " + e.getMessage());
    }

7.4.7. acceptSecContext

 public byte[] acceptSecContext(byte[] inTok, int offset, int len)
            throws GSSException
 Called by the context acceptor upon receiving a token from the peer.
 This call is equivalent to the stream-based method except that the
 token buffers are handled as byte arrays instead of using stream
 objects.
 This method may return an output token that the application will need
 to send to the peer for further processing by the init call.
 The "null" return value indicates that no token needs to be sent to
 the peer.  The application can call isEstablished() to determine if
 the context establishment phase is complete for this peer.  A return
 value of "false" from isEstablished() indicates that more tokens are
 expected to be supplied to this method.

Upadhyay & Malkani Standards Track [Page 59] RFC 5653 Java GSS-API Update August 2009

 Note that it is possible that acceptSecContext() will return a token
 for the peer and isEstablished() will return "true" also.  This
 indicates that the token needs to be sent to the peer, but the local
 end of the context is now fully established.
 Upon completion of the context establishment, the available context
 options may be queried through the get methods.
 Parameters:
    inTok:        Token generated by the peer.
    offset:       The offset within the inTok where the token begins.
    len:          The length of the token within the inTok (starting
                  at the offset).

7.4.8. Example Code

    // acquire server credentials
    GSSCredential server = mgr.createCredential(...);
    // create acceptor GSS-API context from the default provider
    GSSContext context = mgr.createContext(server, null);
    try {
        do {
            byte[] inTok = readToken();
            byte[] outTok = context.acceptSecContext(inTok, 0,
                            inTok.length);
            // possibly send token to peer
            if (outTok != null)
                sendToken(outTok);
            // check if local context establishment is complete
            if (context.isEstablished())
                break;
        } while (true);
    } catch (GSSException e) {
       print("GSS-API error: " + e.getMessage());
    }

Upadhyay & Malkani Standards Track [Page 60] RFC 5653 Java GSS-API Update August 2009

7.4.9. acceptSecContext

 public void acceptSecContext(InputStream inStream,
                  OutputStream outStream) throws GSSException
 Called by the context acceptor upon receiving a token from the peer.
 This call is equivalent to the byte array method.  It may write an
 output token to the outStream, which the application will need to
 send to the peer for processing by its initSecContext method.
 Typically, the application would do so by calling the flush() method
 on an OutputStream that encapsulates the connection between the two
 peers.  The application can call isEstablished() to determine if the
 context establishment phase is complete for this peer.  A return
 value of "false" from isEstablished() indicates that more tokens are
 expected to be supplied to this method.
 Note that it is possible that acceptSecContext() will return a token
 for the peer and isEstablished() will return "true" also.  This
 indicates that the token needs to be sent to the peer, but the local
 end of the context is now fully established.
 The GSS-API authentication tokens contain a definitive start and end.
 This method will attempt to read one of these tokens per invocation,
 and may block on the stream if only part of the token is available.
 Upon completion of the context establishment, the available context
 options may be queried through the get methods.
 Parameters:
    inStream:     Contains the token generated by the peer.
    outStream:    Output stream where the output token will be
                  written.  During the final stage of context
                  establishment, there may be no bytes written.

7.4.10. Example Code

 This sample code merely demonstrates the token exchange during the
 context establishment phase.  It is expected that most Java
 applications will use custom implementations of the Input and Output
 streams that encapsulate the communication routines.  For instance, a
 simple read on the application InputStream, when called by the
 Context, might cause a token to be read from the peer, and a simple
 flush() on the application OutputStream might cause a previously
 written token to be transmitted to the peer.

Upadhyay & Malkani Standards Track [Page 61] RFC 5653 Java GSS-API Update August 2009

    // acquire server credentials
    GSSCredential server = mgr.createCredential(...);
    // create acceptor GSS-API context from the default provider
    GSSContext context = mgr.createContext(server, null);
    // use standard java.io stream objects
    ByteArrayOutputStream os = new ByteArrayOutputStream();
    ByteArrayInputStream is = null;
    try {
        do {
            is = recvToken();
            context.acceptSecContext(is, os);
            // possibly send token to peer
            if (os.size() > 0)
                sendToken(os);
            // check if local context establishment is complete
            if (context.isEstablished())
                break;
        } while (true);
    } catch (GSSException e) {
        print("GSS-API error: " + e.getMessage());
    }

7.4.11. isEstablished

 public boolean isEstablished()
 Used during context establishment to determine the state of the
 context.  Returns "true" if this is a fully established context on
 the caller's side and no more tokens are needed from the peer.
 Should be called after a call to initSecContext() or
 acceptSecContext() when no GSSException is thrown.

7.4.12. dispose

 public void dispose() throws GSSException
 Releases any system resources and cryptographic information stored in
 the context object.  This will invalidate the context.

Upadhyay & Malkani Standards Track [Page 62] RFC 5653 Java GSS-API Update August 2009

7.4.13. getWrapSizeLimit

 public int getWrapSizeLimit(int qop, boolean confReq,
            int maxTokenSize) throws GSSException
 Returns the maximum message size that, if presented to the wrap
 method with the same confReq and qop parameters, will result in an
 output token containing no more than the maxTokenSize bytes.
 This call is intended for use by applications that communicate over
 protocols that impose a maximum message size.  It enables the
 application to fragment messages prior to applying protection.
 GSS-API implementations are recommended but not required to detect
 invalid QOP values when getWrapSizeLimit is called.  This routine
 guarantees only a maximum message size, not the availability of
 specific QOP values for message protection.
 Successful completion of this call does not guarantee that wrap will
 be able to protect a message of the computed length, since this
 ability may depend on the availability of system resources at the
 time that wrap is called.  However, if the implementation itself
 imposes an upper limit on the length of messages that may be
 processed by wrap, the implementation should not return a value that
 is greater than this length.
 Parameters:
    qop:          Indicates the level of protection wrap will be asked
                  to provide.
    confReq:      Indicates if wrap will be asked to provide privacy
                  service.
    maxTokenSize: The desired maximum size of the token emitted by
                  wrap.

7.4.14. wrap

 public byte[] wrap(byte[] inBuf, int offset, int len,
                    MessageProp msgProp) throws GSSException
 Applies per-message security services over the established security
 context.  The method will return a token with a cryptographic MIC and
 may optionally encrypt the specified inBuf.  This method is
 equivalent in functionality to its stream counterpart.  The returned
 byte array will contain both the MIC and the message.

Upadhyay & Malkani Standards Track [Page 63] RFC 5653 Java GSS-API Update August 2009

 The MessageProp object is instantiated by the application and used to
 specify a QOP value that selects cryptographic algorithms, and a
 privacy service to optionally encrypt the message.  The underlying
 mechanism that is used in the call may not be able to provide the
 privacy service.  It sets the actual privacy service that it does
 provide in this MessageProp object, which the caller should then
 query upon return.  If the mechanism is not able to provide the
 requested QOP, it throws a GSSException with the BAD_QOP code.
 Since some application-level protocols may wish to use tokens emitted
 by wrap to provide "secure framing", implementations should support
 the wrapping of zero-length messages.
 The application will be responsible for sending the token to the
 peer.
 Parameters:
    inBuf:        Application data to be protected.
    offset:       The offset within the inBuf where the data begins.
    len:          The length of the data within the inBuf (starting at
                  the offset).
    msgProp:      Instance of MessageProp that is used by the
                  application to set the desired QOP and privacy
                  state.  Set the desired QOP to 0 to request the
                  default QOP.  Upon return from this method, this
                  object will contain the actual privacy state that
                  was applied to the message by the underlying
                  mechanism.

7.4.15. wrap

 public void wrap(InputStream inStream, OutputStream outStream,
                  MessageProp msgProp) throws GSSException
 Allows to apply per-message security services over the established
 security context.  The method will produce a token with a
 cryptographic MIC and may optionally encrypt the message in inStream.
 The outStream will contain both the MIC and the message.
 The MessageProp object is instantiated by the application and used to
 specify a QOP value that selects cryptographic algorithms, and a
 privacy service to optionally encrypt the message.  The underlying
 mechanism that is used in the call may not be able to provide the
 privacy service.  It sets the actual privacy service that it does

Upadhyay & Malkani Standards Track [Page 64] RFC 5653 Java GSS-API Update August 2009

 provide in this MessageProp object, which the caller should then
 query upon return.  If the mechanism is not able to provide the
 requested QOP, it throws a GSSException with the BAD_QOP code.
 Since some application-level protocols may wish to use tokens emitted
 by wrap to provide "secure framing", implementations should support
 the wrapping of zero-length messages.
 The application will be responsible for sending the token to the
 peer.
 Parameters:
    inStream:     Input stream containing the application data to be
                  protected.
    outStream:    The output stream to which to write the protected
                  message.  The application is responsible for sending
                  this to the other peer for processing in its unwrap
                  method.
    msgProp:      Instance of MessageProp that is used by the
                  application to set the desired QOP and privacy
                  state.  Set the desired QOP to 0 to request the
                  default QOP.  Upon return from this method, this
                  object will contain the actual privacy state that
                  was applied to the message by the underlying
                  mechanism.

7.4.16. unwrap

 public byte[] unwrap(byte[] inBuf, int offset, int len,
                      MessageProp msgProp) throws GSSException
 Used by the peer application to process tokens generated with the
 wrap call.  This call is equal in functionality to its stream
 counterpart.  The method will return the message supplied in the peer
 application to the wrap call, verifying the embedded MIC.
 The MessageProp object is instantiated by the application and is used
 by the underlying mechanism to return information to the caller such
 as the QOP, whether confidentiality was applied to the message, and
 other supplementary message state information.
 Since some application-level protocols may wish to use tokens emitted
 by wrap to provide "secure framing", implementations should support
 the wrapping and unwrapping of zero-length messages.

Upadhyay & Malkani Standards Track [Page 65] RFC 5653 Java GSS-API Update August 2009

 Parameters:
    inBuf:        GSS-API wrap token received from peer.
    offset:       The offset within the inBuf where the token begins.
    len:          The length of the token within the inBuf (starting
                  at the offset).
    msgProp:      Upon return from the method, this object will
                  contain the applied QOP, the privacy state of the
                  message, and supplementary information, described in
                  section 5.12.3, stating whether the token was a
                  duplicate, old, out of sequence, or arriving after a
                  gap.

7.4.17. unwrap

 public void unwrap(InputStream inStream, OutputStream outStream,
                    MessageProp msgProp) throws GSSException
 Used by the peer application to process tokens generated with the
 wrap call.  This call is equal in functionality to its byte array
 counterpart.  It will produce the message supplied in the peer
 application to the wrap call, verifying the embedded MIC.
 The MessageProp object is instantiated by the application and is used
 by the underlying mechanism to return information to the caller such
 as the QOP, whether confidentiality was applied to the message, and
 other supplementary message state information.
 Since some application-level protocols may wish to use tokens emitted
 by wrap to provide "secure framing", implementations should support
 the wrapping and unwrapping of zero-length messages.
 Parameters:
    inStream:     Input stream containing the GSS-API wrap token
                  received from the peer.
    outStream:    The output stream to which to write the application
                  message.

Upadhyay & Malkani Standards Track [Page 66] RFC 5653 Java GSS-API Update August 2009

    msgProp:      Upon return from the method, this object will
                  contain the applied QOP, the privacy state of the
                  message, and supplementary information, described in
                  section 5.12.3, stating whether the token was a
                  duplicate, old, out of sequence, or arriving after a
                  gap.

7.4.18. getMIC

 public byte[] getMIC(byte[] inMsg, int offset, int len,
                      MessageProp msgProp) throws GSSException
 Returns a token containing a cryptographic MIC for the supplied
 message for transfer to the peer application.  Unlike wrap, which
 encapsulates the user message in the returned token, only the message
 MIC is returned in the output token.  This method is identical in
 functionality to its stream counterpart.
 Note that privacy can only be applied through the wrap call.
 Since some application-level protocols may wish to use tokens emitted
 by getMIC to provide "secure framing", implementations should support
 derivation of MICs from zero-length messages.
 Parameters:
    inMsg:        Message over which to generate MIC.
    offset:       The offset within the inMsg where the token begins.
    len:          The length of the token within the inMsg (starting
                  at the offset).
    msgProp:      Instance of MessageProp that is used by the
                  application to set the desired QOP.  Set the desired
                  QOP to 0 in msgProp to request the default QOP.
                  Alternatively, pass in "null" for msgProp to request
                  default QOP.

Upadhyay & Malkani Standards Track [Page 67] RFC 5653 Java GSS-API Update August 2009

7.4.19. getMIC

 public void getMIC(InputStream inStream, OutputStream outStream,
                    MessageProp msgProp) throws GSSException
 Produces a token containing a cryptographic MIC for the supplied
 message, for transfer to the peer application.  Unlike wrap, which
 encapsulates the user message in the returned token, only the message
 MIC is produced in the output token.  This method is identical in
 functionality to its byte array counterpart.
 Note that privacy can only be applied through the wrap call.
 Since some application-level protocols may wish to use tokens emitted
 by getMIC to provide "secure framing", implementations should support
 derivation of MICs from zero-length messages.
 Parameters:
    inStream:     Input stream containing the message over which to
                  generate MIC.
    outStream:    Output stream to which to write the GSS-API output
                  token.
    msgProp:      Instance of MessageProp that is used by the
                  application to set the desired QOP.  Set the desired
                  QOP to 0 in msgProp to request the default QOP.
                  Alternatively, pass in "null" for msgProp to request
                  default QOP.

7.4.20. verifyMIC

 public void verifyMIC(byte[] inTok, int tokOffset, int tokLen,
                       byte[] inMsg, int msgOffset, int msgLen,
                       MessageProp msgProp) throws GSSException
 Verifies the cryptographic MIC, contained in the token parameter,
 over the supplied message.  This method is equivalent in
 functionality to its stream counterpart.
 The MessageProp object is instantiated by the application and is used
 by the underlying mechanism to return information to the caller such
 as the QOP indicating the strength of protection that was applied to
 the message and other supplementary message state information.

Upadhyay & Malkani Standards Track [Page 68] RFC 5653 Java GSS-API Update August 2009

 Since some application-level protocols may wish to use tokens emitted
 by getMIC to provide "secure framing", implementations should support
 the calculation and verification of MICs over zero-length messages.
 Parameters:
    inTok:        Token generated by peer's getMIC method.
    tokOffset:    The offset within the inTok where the token begins.
    tokLen:       The length of the token within the inTok (starting
                  at the offset).
    inMsg:        Application message over which to verify the
                  cryptographic MIC.
    msgOffset:    The offset within the inMsg where the message
                  begins.
    msgLen:       The length of the message within the inMsg (starting
                  at the offset).
    msgProp:      Upon return from the method, this object will
                  contain the applied QOP and supplementary
                  information, described in section 5.12.3, stating
                  whether the token was a duplicate, old, out of
                  sequence, or arriving after a gap.  The
                  confidentiality state will be set to "false".

7.4.21. verifyMIC

 public void verifyMIC(InputStream tokStream, InputStream msgStream,
                       MessageProp msgProp) throws GSSException
 Verifies the cryptographic MIC, contained in the token parameter,
 over the supplied message.  This method is equivalent in
 functionality to its byte array counterpart.
 The MessageProp object is instantiated by the application and is used
 by the underlying mechanism to return information to the caller such
 as the QOP indicating the strength of protection that was applied to
 the message and other supplementary message state information.
 Since some application-level protocols may wish to use tokens emitted
 by getMIC to provide "secure framing", implementations should support
 the calculation and verification of MICs over zero-length messages.

Upadhyay & Malkani Standards Track [Page 69] RFC 5653 Java GSS-API Update August 2009

 Parameters:
    tokStream:    Input stream containing the token generated by the
                  peer's getMIC method.
    msgStream:    Input stream containing the application message over
                  which to verify the cryptographic MIC.
    msgProp:      Upon return from the method, this object will
                  contain the applied QOP and supplementary
                  information, described in section 5.12.3, stating
                  whether the token was a duplicate, old, out of
                  sequence, or arriving after a gap.  The
                  confidentiality state will be set to "false".

7.4.22. export

 public byte[] export() throws GSSException
 Provided to support the sharing of work between multiple processes.
 This routine will typically be used by the context acceptor, in an
 application where a single process receives incoming connection
 requests and accepts security contexts over them, then passes the
 established context to one or more other processes for message
 exchange.
 This method deactivates the security context and creates an inter-
 process token which, when passed to the byte array constructor of the
 GSSContext interface in another process, will re-activate the context
 in the second process.  Only a single instantiation of a given
 context may be active at any one time; a subsequent attempt by a
 context exporter to access the exported security context will fail.
 The implementation may constrain the set of processes by which the
 inter-process token may be imported, either as a function of local
 security policy, or as a result of implementation decisions.  For
 example, some implementations may constrain contexts to be passed
 only between processes that run under the same account, or which are
 part of the same process group.
 The inter-process token may contain security-sensitive information
 (for example, cryptographic keys).  While mechanisms are encouraged
 to either avoid placing such sensitive information within inter-
 process tokens or to encrypt the token before returning it to the
 application, in a typical GSS-API implementation, this may not be
 possible.  Thus, the application must take care to protect the
 inter-process token, and ensure that any process to which the token
 is transferred is trustworthy.

Upadhyay & Malkani Standards Track [Page 70] RFC 5653 Java GSS-API Update August 2009

7.4.23. requestMutualAuth

 public void requestMutualAuth(boolean state) throws GSSException
 Sets the request state of the mutual authentication flag for the
 context.  This method is only valid before the context creation
 process begins and only for the initiator.
 Parameters:
    state:        Boolean representing if mutual authentication should
                  be requested during context establishment.

7.4.24. requestReplayDet

 public void requestReplayDet(boolean state) throws GSSException
 Sets the request state of the replay detection service for the
 context.  This method is only valid before the context creation
 process begins and only for the initiator.
 Parameters:
    state:        Boolean representing if replay detection is desired
                  over the established context.

7.4.25. requestSequenceDet

 public void requestSequenceDet(boolean state) throws GSSException
 Sets the request state for the sequence checking service of the
 context.  This method is only valid before the context creation
 process begins and only for the initiator.
 Parameters:
    state:        Boolean representing if sequence detection is
                  desired over the established context.

7.4.26. requestCredDeleg

 public void requestCredDeleg(boolean state) throws GSSException
 Sets the request state for the credential delegation flag for the
 context.  This method is only valid before the context creation
 process begins and only for the initiator.

Upadhyay & Malkani Standards Track [Page 71] RFC 5653 Java GSS-API Update August 2009

 Parameters:
    state:        Boolean representing if credential delegation is
                  desired.

7.4.27. requestAnonymity

 public void requestAnonymity(boolean state) throws GSSException
 Requests anonymous support over the context.  This method is only
 valid before the context creation process begins and only for the
 initiator.
 Parameters:
    state:        Boolean representing if anonymity support is
                  requested.

7.4.28. requestConf

 public void requestConf(boolean state) throws GSSException
 Requests that confidentiality service be available over the context.
 This method is only valid before the context creation process begins
 and only for the initiator.
 Parameters:
    state:        Boolean indicating if confidentiality services are
                  to be requested for the context.

7.4.29. requestInteg

 public void requestInteg(boolean state) throws GSSException
 Requests that integrity services be available over the context.  This
 method is only valid before the context creation process begins and
 only for the initiator.
 Parameters:
    state:        Boolean indicating if integrity services are to be
                  requested for the context.

Upadhyay & Malkani Standards Track [Page 72] RFC 5653 Java GSS-API Update August 2009

7.4.30. requestLifetime

 public void requestLifetime(int lifetime) throws GSSException
 Sets the desired lifetime for the context in seconds.  This method is
 only valid before the context creation process begins and only for
 the initiator.  Use GSSContext.INDEFINITE_LIFETIME and
 GSSContext.DEFAULT_LIFETIME to request indefinite or default context
 lifetime.
 Parameters:
    lifetime:     The desired context lifetime in seconds.

7.4.31. setChannelBinding

 public void setChannelBinding(ChannelBinding cb) throws GSSException
 Sets the channel bindings to be used during context establishment.
 This method is only valid before the context creation process begins.
 Parameters:
    cb:           Channel bindings to be used.

7.4.32. getCredDelegState

 public boolean getCredDelegState()
 Returns the state of the delegated credentials for the context.  When
 issued before context establishment is completed or when the
 isProtReady method returns "false", it returns the desired state;
 otherwise, it will indicate the actual state over the established
 context.

7.4.33. getMutualAuthState

 public boolean getMutualAuthState()
 Returns the state of the mutual authentication option for the
 context.  When issued before context establishment completes or when
 the isProtReady method returns "false", it returns the desired state;
 otherwise, it will indicate the actual state over the established
 context.

Upadhyay & Malkani Standards Track [Page 73] RFC 5653 Java GSS-API Update August 2009

7.4.34. getReplayDetState

 public boolean getReplayDetState()
 Returns the state of the replay detection option for the context.
 When issued before context establishment completes or when the
 isProtReady method returns "false", it returns the desired state;
 otherwise, it will indicate the actual state over the established
 context.

7.4.35. getSequenceDetState

 public boolean getSequenceDetState()
 Returns the state of the sequence detection option for the context.
 When issued before context establishment completes or when the
 isProtReady method returns "false", it returns the desired state;
 otherwise, it will indicate the actual state over the established
 context.

7.4.36. getAnonymityState

 public boolean getAnonymityState()
 Returns "true" if this is an anonymous context.  When issued before
 context establishment completes or when the isProtReady method
 returns "false", it returns the desired state; otherwise, it will
 indicate the actual state over the established context.

7.4.37. isTransferable

 public boolean isTransferable() throws GSSException
 Returns "true" if the context is transferable to other processes
 through the use of the export method.  This call is only valid on
 fully established contexts.

7.4.38. isProtReady

 public boolean isProtReady()
 Returns "true" if the per-message operations can be applied over the
 context.  Some mechanisms may allow the usage of per-message
 operations before the context is fully established.  This will also
 indicate that the get methods will return actual context state
 characteristics instead of the desired ones.

Upadhyay & Malkani Standards Track [Page 74] RFC 5653 Java GSS-API Update August 2009

7.4.39. getConfState

 public boolean getConfState()
 Returns the confidentiality service state over the context.  When
 issued before context establishment completes or when the isProtReady
 method returns "false", it returns the desired state; otherwise, it
 will indicate the actual state over the established context.

7.4.40. getIntegState

 public boolean getIntegState()
 Returns the integrity service state over the context.  When issued
 before context establishment completes or when the isProtReady method
 returns "false", it returns the desired state; otherwise, it will
 indicate the actual state over the established context.

7.4.41. getLifetime

 public int getLifetime()
 Returns the context lifetime in seconds.  When issued before context
 establishment completes or when the isProtReady method returns
 "false", it returns the desired lifetime; otherwise, it will indicate
 the remaining lifetime for the context.

7.4.42. getSrcName

 public GSSName getSrcName() throws GSSException
 Returns the name of the context initiator.  This call is valid only
 after the context is fully established or the isProtReady method
 returns "true".  It is guaranteed to return an MN.

7.4.43. getTargName

 public GSSName getTargName() throws GSSException
 Returns the name of the context target (acceptor).  This call is
 valid only after the context is fully established or the isProtReady
 method returns "true".  It is guaranteed to return an MN.

Upadhyay & Malkani Standards Track [Page 75] RFC 5653 Java GSS-API Update August 2009

7.4.44. getMech

 public Oid getMech() throws GSSException
 Returns the mechanism oid for this context.  This method may be
 called before the context is fully established, but the mechanism
 returned may change on successive calls in negotiated mechanism case.

7.4.45. getDelegCred

 public GSSCredential getDelegCred() throws GSSException
 Returns the delegated credential object on the acceptor's side.  To
 check for availability of delegated credentials call
 getDelegCredState.  This call is only valid on fully established
 contexts.

7.4.46. isInitiator

 public boolean isInitiator() throws GSSException
 Returns "true" if this is the initiator of the context.  This call is
 only valid after the context creation process has started.

7.5. public class MessageProp

 This is a utility class used within the per-message GSSContext
 methods to convey per-message properties.
 When used with the GSSContext interface's wrap and getMIC methods, an
 instance of this class is used to indicate the desired QOP and to
 request if confidentiality services are to be applied to caller
 supplied data (wrap only).  To request default QOP, the value of 0
 should be used for QOP.
 When used with the unwrap and verifyMIC methods of the GSSContext
 interface, an instance of this class will be used to indicate the
 applied QOP and confidentiality services over the supplied message.
 In the case of verifyMIC, the confidentiality state will always be
 "false".  Upon return from these methods, this object will also
 contain any supplementary status values applicable to the processed
 token.  The supplementary status values can indicate old tokens, out
 of sequence tokens, gap tokens, or duplicate tokens.

Upadhyay & Malkani Standards Track [Page 76] RFC 5653 Java GSS-API Update August 2009

7.5.1. Constructors

 public MessageProp(boolean privState)
 Constructor that sets QOP to 0 indicating that the default QOP is
 requested.
 Parameters:
    privState:    The desired privacy state. "true" for privacy and
                  "false" for integrity only.
 public MessageProp(int qop, boolean privState)
 Constructor that sets the values for the qop and privacy state.
 Parameters:
    qop:          The desired QOP.  Use 0 to request a default QOP.
    privState:    The desired privacy state. "true" for privacy and
                  "false" for integrity only.

7.5.2. getQOP

 public int getQOP()
 Retrieves the QOP value.

7.5.3. getPrivacy

 public boolean getPrivacy()
 Retrieves the privacy state.

7.5.4. getMinorStatus

 public int getMinorStatus()
 Retrieves the minor status that the underlying mechanism might have
 set.

7.5.5. getMinorString

 public String getMinorString()
 Returns a string explaining the mechanism-specific error code. "null"
 will be returned when no mechanism error code has been set.

Upadhyay & Malkani Standards Track [Page 77] RFC 5653 Java GSS-API Update August 2009

7.5.6. setQOP

 public void setQOP(int qopVal)
 Sets the QOP value.
 Parameters:
    qopVal:       The QOP value to be set.  Use 0 to request a default
                  QOP value.

7.5.7. setPrivacy

 public void setPrivacy(boolean privState)
 Sets the privacy state.
 Parameters:
    privState:    The privacy state to set.

7.5.8. isDuplicateToken

 public boolean isDuplicateToken()
 Returns "true" if this is a duplicate of an earlier token.

7.5.9. isOldToken

 public boolean isOldToken()
 Returns "true" if the token's validity period has expired.

7.5.10. isUnseqToken

 public boolean isUnseqToken()
 Returns "true" if a later token has already been processed.

7.5.11. isGapToken

 public boolean isGapToken()
 Returns "true" if an expected per-message token was not received.

Upadhyay & Malkani Standards Track [Page 78] RFC 5653 Java GSS-API Update August 2009

7.5.12. setSupplementaryStates

 public void setSupplementaryStates(boolean duplicate,
                boolean old, boolean unseq, boolean gap,
                int minorStatus, String minorString)
 This method sets the state for the supplementary information flags
 and the minor status in MessageProp.  It is not used by the
 application but by the GSS implementation to return this information
 to the caller of a per-message context method.
 Parameters:
    duplicate:    "true" if the token was a duplicate of an earlier
                  token; otherwise, "false".
    old:          "true" if the token's validity period has expired;
                  otherwise, "false".
    unseq:        "true" if a later token has already been processed;
                  otherwise, "false".
    gap:          "true" if one or more predecessor tokens have not
                  yet been successfully processed; otherwise, "false".
    minorStatus:  The integer minor status code that the underlying
                  mechanism wants to set.
    minorString:  The textual representation of the minorStatus value.

7.6. public class ChannelBinding

 The GSS-API accommodates the concept of caller-provided channel
 binding information.  Channel bindings are used to strengthen the
 quality with which peer entity authentication is provided during
 context establishment.  They enable the GSS-API callers to bind the
 establishment of the security context to relevant characteristics
 like addresses or to application-specific data.
 The caller initiating the security context must determine the
 appropriate channel binding values to set in the GSSContext object.
 The acceptor must provide an identical binding in order to validate
 that received tokens possess correct channel-related characteristics.
 Use of channel bindings is optional in GSS-API.  Since channel-
 binding information may be transmitted in context establishment
 tokens, applications should therefore not use confidential data as
 channel-binding components.

Upadhyay & Malkani Standards Track [Page 79] RFC 5653 Java GSS-API Update August 2009

7.6.1. Constructors

 public ChannelBinding(InetAddress initAddr, InetAddress acceptAddr,
                       byte[] appData)
 Create a ChannelBinding object with user-supplied address information
 and data. "null" values can be used for any fields that the
 application does not want to specify.
 Parameters:
    initAddr:     The address of the context initiator. "null" value
                  can be supplied to indicate that the application
                  does not want to set this value.
    acceptAddr:   The address of the context acceptor. "null" value
                  can be supplied to indicate that the application
                  does not want to set this value.
    appData:      Application-supplied data to be used as part of the
                  channel bindings. "null" value can be supplied to
                  indicate that the application does not want to set
                  this value.
 public ChannelBinding(byte[] appData)
 Creates a ChannelBinding object without any addressing information.
 Parameters:
    appData:      Application supplied data to be used as part of the
                  channel bindings.

7.6.2. getInitiatorAddress

 public InetAddress getInitiatorAddress()
 Returns the initiator's address for this channel binding. "null" is
 returned if the address has not been set.

7.6.3. getAcceptorAddress

 public InetAddress getAcceptorAddress()
 Returns the acceptor's address for this channel binding. "null" is
 returned if the address has not been set.

Upadhyay & Malkani Standards Track [Page 80] RFC 5653 Java GSS-API Update August 2009

7.6.4. getApplicationData

 public byte[] getApplicationData()
 Returns application data being used as part of the ChannelBinding.
 "null" is returned if no application data has been specified for the
 channel binding.

7.6.5. equals

 public boolean equals(Object obj)
 Returns "true" if two channel bindings match.  (Note that the Java
 language specification requires that two objects that are equal
 according to the equals(Object) method must return the same integer
 result when the hashCode() method is called on them.)
 Parameters:
    obj:          Another channel binding with which to compare.

7.7. public class Oid

 This class represents Universal Object Identifiers (Oids) and their
 associated operations.
 Oids are hierarchically globally interpretable identifiers used
 within the GSS-API framework to identify mechanisms and name formats.
 The structure and encoding of Oids is defined in ISOIEC-8824 and
 ISOIEC-8825.  For example, the Oid representation of the Kerberos v5
 mechanism is "1.2.840.113554.1.2.2".
 The GSSName name class contains public static Oid objects
 representing the standard name types defined in GSS-API.

7.7.1. Constructors

 public Oid(String strOid) throws GSSException
 Creates an Oid object from a string representation of its integer
 components (e.g., "1.2.840.113554.1.2.2").
 Parameters:
    strOid:       The string representation for the oid.
 public Oid(InputStream derOid) throws GSSException

Upadhyay & Malkani Standards Track [Page 81] RFC 5653 Java GSS-API Update August 2009

 Creates an Oid object from its DER encoding.  This refers to the full
 encoding including tag and length.  The structure and encoding of
 Oids is defined in ISOIEC-8824 and ISOIEC-8825.  This method is
 identical in functionality to its byte array counterpart.
 Parameters:
    derOid:       Stream containing the DER-encoded oid.
 public Oid(byte[] DEROid) throws GSSException
 Creates an Oid object from its DER encoding.  This refers to the full
 encoding including tag and length.  The structure and encoding of
 Oids is defined in ISOIEC-8824 and ISOIEC-8825.  This method is
 identical in functionality to its byte array counterpart.
 Parameters:
    derOid:       Byte array storing a DER-encoded oid.

7.7.2. toString

 public String toString()
 Returns a string representation of the oid's integer components in
 dot separated notation (e.g., "1.2.840.113554.1.2.2").

7.7.3. equals

 public boolean equals(Object Obj)
 Returns "true" if the two Oid objects represent the same oid value.
 (Note that the Java language specification [JLS] requires that two
 objects that are equal according to the equals(Object) method must
 return the same integer result when the hashCode() method is called
 on them.)
 Parameters:
    obj:          Another Oid object with which to compare.

7.7.4. getDER

 public byte[] getDER()
 Returns the full ASN.1 DER encoding for this oid object, which
 includes the tag and length.

Upadhyay & Malkani Standards Track [Page 82] RFC 5653 Java GSS-API Update August 2009

7.7.5. containedIn

 public boolean containedIn(Oid[] oids)
 A utility method to test if an Oid object is contained within the
 supplied Oid object array.
 Parameters:
    oids:         An array of oids to search.

7.8. public class GSSException extends Exception

 This exception is thrown whenever a fatal GSS-API error occurs
 including mechanism-specific errors.  It may contain both, the major
 and minor, GSS-API status codes.  The mechanism implementors are
 responsible for setting appropriate minor status codes when throwing
 this exception.  Aside from delivering the numeric error code(s) to
 the caller, this class performs the mapping from their numeric values
 to textual representations.  All Java GSS-API methods are declared
 throwing this exception.
 All implementations are encouraged to use the Java
 internationalization techniques to provide local translations of the
 message strings.

7.8.1. Static Constants

 All valid major GSS-API error code values are declared as constants
 in this class.
 public static final int BAD_BINDINGS
 Channel bindings mismatch error.  The value of this constant is 1.
 public static final int BAD_MECH
 Unsupported mechanism requested error.  The value of this constant is
 2.
 public static final int BAD_NAME
 Invalid name provided error.  The value of this constant is 3.
 public static final int BAD_NAMETYPE
 Name of unsupported type provided error.  The value of this constant
 is 4.

Upadhyay & Malkani Standards Track [Page 83] RFC 5653 Java GSS-API Update August 2009

 public static final int BAD_STATUS
 Invalid status code error - this is the default status value.  The
 value of this constant is 5.
 public static final int BAD_MIC
 Token had invalid integrity check error.  The value of this constant
 is 6.
 public static final int CONTEXT_EXPIRED
 Specified security context expired error.  The value of this constant
 is 7.
 public static final int CREDENTIALS_EXPIRED
 Expired credentials detected error.  The value of this constant is 8.
 public static final int DEFECTIVE_CREDENTIAL
 Defective credential error.  The value of this constant is 9.
 public static final int DEFECTIVE_TOKEN
 Defective token error.  The value of this constant is 10.
 public static final int FAILURE
 General failure, unspecified at GSS-API level.  The value of this
 constant is 11.
 public static final int NO_CONTEXT
 Invalid security context error.  The value of this constant is 12.
 public static final int NO_CRED
 Invalid credentials error.  The value of this constant is 13.
 public static final int BAD_QOP
 Unsupported QOP value error.  The value of this constant is 14.
 public static final int UNAUTHORIZED
 Operation unauthorized error.  The value of this constant is 15.

Upadhyay & Malkani Standards Track [Page 84] RFC 5653 Java GSS-API Update August 2009

 public static final int UNAVAILABLE
 Operation unavailable error.  The value of this constant is 16.
 public static final int DUPLICATE_ELEMENT
 Duplicate credential element requested error.  The value of this
 constant is 17.
 public static final int NAME_NOT_MN
 Name contains multi-mechanism elements error.  The value of this
 constant is 18.
 public static final int DUPLICATE_TOKEN
 The token was a duplicate of an earlier token.  This is contained in
 an exception only when detected during context establishment, in
 which case it is considered a fatal error.  (Non-fatal supplementary
 codes are indicated via the MessageProp object.)  The value of this
 constant is 19.
 public static final int OLD_TOKEN
 The token's validity period has expired.  This is contained in an
 exception only when detected during context establishment, in which
 case it is considered a fatal error.  (Non-fatal supplementary codes
 are indicated via the MessageProp object.)  The value of this
 constant is 20.
 public static final int UNSEQ_TOKEN
 A later token has already been processed.  This is contained in an
 exception only when detected during context establishment, in which
 case it is considered a fatal error.  (Non-fatal supplementary codes
 are indicated via the MessageProp object.)  The value of this
 constant is 21.
 public static final int GAP_TOKEN
 An expected per-message token was not received.  This is contained in
 an exception only when detected during context establishment, in
 which case it is considered a fatal error.  (Non-fatal supplementary
 codes are indicated via the MessageProp object.)  The value of this
 constant is 22.

Upadhyay & Malkani Standards Track [Page 85] RFC 5653 Java GSS-API Update August 2009

7.8.2. Constructors

 public GSSException(int majorCode)
 Creates a GSSException object with a specified major code.
 Parameters:
    majorCode:    The GSS error code causing this exception to be
                  thrown.
 public GSSException(int majorCode, int minorCode, String minorString)
 Creates a GSSException object with the specified major code, minor
 code, and minor code textual explanation.  This constructor is to be
 used when the exception is originating from the security mechanism.
 It allows to specify the GSS code and the mechanism code.
 Parameters:
    majorCode:    The GSS error code causing this exception to be
                  thrown.
    minorCode:    The mechanism error code causing this exception to
                  be thrown.
    minorString:  The textual explanation of the mechanism error code.

7.8.3. getMajor

 public int getMajor()
 Returns the major code representing the GSS error code that caused
 this exception to be thrown.

7.8.4. getMinor

 public int getMinor()
 Returns the mechanism error code that caused this exception.  The
 minor code is set by the underlying mechanism.  Value of 0 indicates
 that mechanism error code is not set.

Upadhyay & Malkani Standards Track [Page 86] RFC 5653 Java GSS-API Update August 2009

7.8.5. getMajorString

 public String getMajorString()
 Returns a string explaining the GSS major error code causing this
 exception to be thrown.

7.8.6. getMinorString

 public String getMinorString()
 Returns a string explaining the mechanism-specific error code. "null"
 will be returned when no mechanism error code has been set.

7.8.7. setMinor

 public void setMinor(int minorCode, String message)
 Used internally by the GSS-API implementation and the underlying
 mechanisms to set the minor code and its textual representation.
 Parameters:
    minorCode:    The mechanism-specific error code.
    message:      A textual explanation of the mechanism error code.

7.8.8. toString

 public String toString()
 Returns a textual representation of both the major and minor status
 codes.

7.8.9. getMessage

 public String getMessage()
 Returns a detailed message of this exception.  Overrides
 Throwable.getMessage.  It is customary in Java to use this method to
 obtain exception information.

Upadhyay & Malkani Standards Track [Page 87] RFC 5653 Java GSS-API Update August 2009

8. Sample Applications

8.1. Simple GSS Context Initiator

    import org.ietf.jgss.*;
    /**
     * This is a partial sketch for a simple client program that acts
     * as a GSS context initiator.  It illustrates how to use the Java
     * bindings for the GSS-API specified in
     * Generic Security Service API Version 2 : Java bindings
     *
     *
     * This code sketch assumes the existence of a GSS-API
     * implementation that supports the mechanism that it will need
     * and is present as a library package (org.ietf.jgss) either as
     * part of the standard JRE or in the CLASSPATH the application
     * specifies.
     */
     public class SimpleClient {
         private String serviceName; // name of peer (i.e., server)
         private GSSCredential clientCred = null;
         private GSSContext context = null;
         private Oid mech; // underlying mechanism to use
         private GSSManager mgr = GSSManager.getInstance();
         ...
         ...
         private void clientActions() {
             initializeGSS();
             establishContext();
             doCommunication();
         }
        /**
         * Acquire credentials for the client.
         */
         private void initializeGSS() {
           try {
             clientCred = mgr.createCredential(null /*default princ*/,
                 GSSCredential.INDEFINITE_LIFETIME /* max lifetime */,
                 mech /* mechanism to use */,

Upadhyay & Malkani Standards Track [Page 88] RFC 5653 Java GSS-API Update August 2009

                 GSSCredential.INITIATE_ONLY /* init context */);
             print("GSSCredential created for " +
                      cred.getName().toString());
             print("Credential lifetime (sec)=" +
                      cred.getRemainingLifetime());
            } catch (GSSException e) {
                print("GSS-API error in credential acquisition: "
                      + e.getMessage());
                    ...
                    ...
            }
            ...
            ...
          }
         /**
          * Does the security context establishment with the
          * server.
          */
          private void establishContext() {
              byte[] inToken = new byte[0];
              byte[] outToken = null;
            try {
                 GSSName peer = mgr.createName(serviceName,
                                        GSSName.NT_HOSTBASED_SERVICE);
                 context = mgr.createContext(peer, mech, gssCred,
                        GSSContext.INDEFINITE_LIFETIME/*lifetime*/);
                 // Will need to support confidentiality
                 context.requestConf(true);
                 while (!context.isEstablished()) {
                    outToken = context.initSecContext(inToken, 0,
                                                      inToken.length);
                    if (outToken != null)
                        writeGSSToken(outToken);
                    if (!context.isEstablished())
                        inToken = readGSSToken();
                 }

Upadhyay & Malkani Standards Track [Page 89] RFC 5653 Java GSS-API Update August 2009

                 GSSName peer = context.getSrcName();
                 print("Security context established with " + peer +
                   " using underlying mechanism " + mech.toString());
            } catch (GSSException e) {
                 print("GSS-API error during context establishment: "
                       + e.getMessage());
                 ...
                 ...
            }
            ...
            ...
        }
        /**
         * Sends some data to the server and reads back the
         * response.
         */
        private void doCommunication()  {
               byte[] inToken = null;
               byte[] outToken = null;
               byte[] buffer;
               // Container for multiple input-output arguments to and
               // from the per-message routines (e.g., wrap/unwrap).
               MessageProp messgInfo = new MessageProp();
               try {
                    /*
                     * Now send some bytes to the server to be
                     * processed.  They will be integrity protected
                     * but not encrypted for privacy.
                     */
                    buffer = readFromFile();
                    // Set privacy to "false" and use the default QOP
                    messgInfo.setPrivacy(false);
                    outToken = context.wrap(buffer, 0, buffer.length,
                                            messgInfo);
                    writeGSSToken(outToken);
                    /*
                     * Now read the response from the server.
                     */

Upadhyay & Malkani Standards Track [Page 90] RFC 5653 Java GSS-API Update August 2009

                    inToken = readGSSToken();
                    buffer = context.unwrap(inToken, 0,
                                  inToken.length, messgInfo);
                    // All ok if no exception was thrown!
                    GSSName peer = context.getSrcName();
                    print("Message from "  + peer.toString()
                          + " arrived.");
                    print("Was it encrypted? "  +
                          messgInfo.getPrivacy());
                    print("Duplicate Token? "   +
                          messgInfo.isDuplicateToken());
                    print("Old Token? "         +
                          messgInfo.isOldToken());
                    print("Unsequenced Token? " +
                          messgInfo.isUnseqToken());
                    print("Gap Token? "         +
                          messgInfo.isGapToken());
                    ...
                    ...
                } catch (GSSException e) {
                    print("GSS-API error in per-message calls: "
                          + e.getMessage());
                    ...
                    ...
              }
                ...
                ...
        } // end of doCommunication method
        ...
        ...
    } // end of class SimpleClient

Upadhyay & Malkani Standards Track [Page 91] RFC 5653 Java GSS-API Update August 2009

8.2. Simple GSS Context Acceptor

    import org.ietf.jgss.*;
    /**
     * This is a partial sketch for a simple server program that acts
     * as a GSS context acceptor.  It illustrates how to use the Java
     * bindings for the GSS-API specified in
     * Generic Security Service API Version 2 : Java bindings.
     *
     * This code sketch assumes the existence of a GSS-API
     * implementation that supports the mechanisms that it will need
     * and is present as a library package (org.ietf.jgss) either as
     * part of the standard JRE or in the CLASSPATH the application
     * specifies.
     */
    import org.ietf.jgss.*;
    public class SimpleServer {
         private String serviceName;
         private GSSName name;
         private GSSCredential cred;
         private GSSManager mgr;
         ...
         ...
         /**
          * Wait for client connections, establish security contexts
          * and provide service.
          */
            private void loop() {
            ...
            ...
            mgr = GSSManager.getInstance();
            name = mgr.createName(serviceName,
                      GSSName.NT_HOSTBASED_SERVICE);
            cred = mgr.createCredential(name,
                      GSSCredential.INDEFINITE_LIFETIME,
                      null,
                      GSSCredential.ACCEPT_ONLY);

Upadhyay & Malkani Standards Track [Page 92] RFC 5653 Java GSS-API Update August 2009

            // Loop infinitely
            while (true) {
                 Socket s = serverSock.accept();
                 // Start a new thread to serve this connection
                 Thread serverThread = new ServerThread(s);
                 serverThread.start();
            }
        }
        /**
         * Inner class ServerThread whose run() method provides the
         * secure service to a connection.
         */
        private class ServerThread extends Thread {
        ...
        ...
            /**
             * Deals with the connection from one client.  It also
             * handles all GSSException's thrown while talking to
             * this client.
             */
            public void run() {
                 byte[] inToken = null;
                 byte[] outToken = null;
                 byte[] buffer;
                 GSSName peer;
                 // Container for multiple input-output arguments to
                 // and from the per-message routines
                 // (i.e., wrap/unwrap).
                 MessageProp supplInfo = new MessageProp();
                 GSSContext secContext = null;
                 try {
                    // Now do the context establishment loop
                    GSSContext context = mgr.createContext(cred);

Upadhyay & Malkani Standards Track [Page 93] RFC 5653 Java GSS-API Update August 2009

                    while (!context.isEstablished()) {
                        inToken = readGSSToken();
                        outToken = context.acceptSecContext(inToken,
                                                 0, inToken.length);
                        if (outToken != null)
                            writeGSSToken(outToken);
                    }
                    // SimpleServer wants confidentiality to be
                    // available.  Check for it.
                    if (!context.getConfState()){
                        ...
                        ...
                    }
                    GSSName peer = context.getSrcName();
                    Oid mech = context.getMech();
                    print("Security context established with " +
                           peer.toString() +
                          " using underlying mechanism " +
                          mech.toString() +
                          " from Provider " +
                          context.getProvider().getName());
                    // Now read the bytes sent by the client to be
                    // processed.
                    inToken = readGSSToken();
                    // Unwrap the message
                    buffer = context.unwrap(inToken, 0,
                                inToken.length, supplInfo);
                    // All ok if no exception was thrown!
                    // Print other supplementary per-message status
                    // information.
                    print("Message from " +
                            peer.toString() + " arrived.");
                    print("Was it encrypted? " +
                            supplInfo.getPrivacy());
                    print("Duplicate Token? " +
                            supplInfo.isDuplicateToken());
                    print("Old Token? "  + supplInfo.isOldToken());

Upadhyay & Malkani Standards Track [Page 94] RFC 5653 Java GSS-API Update August 2009

                    print("Unsequenced Token? " +
                            supplInfo.isUnseqToken());
                    print("Gap Token? "  + supplInfo.isGapToken());
                    /*
                     * Now process the bytes and send back an
                     * encrypted response.
                     */
                    buffer = serverProcess(buffer);
                    // Encipher it and send it across
                    supplInfo.setPrivacy(true); // privacy requested
                    supplInfo.setQOP(0); // default QOP
                    outToken = context.wrap(buffer, 0, buffer.length,
                                               supplInfo);
                    writeGSSToken(outToken);
                } catch (GSSException e) {
                    print("GSS-API Error: " + e.getMessage());
                    // Alternatively, could call e.getMajorMessage()
                    // and e.getMinorMessage()
                    print("Abandoning security context.");
                    ...
                    ...
                }
                ...
                ...
            } // end of run method in ServerThread
         } // end of inner class ServerThread
         ...
         ...
        } // end of class SimpleServer

Upadhyay & Malkani Standards Track [Page 95] RFC 5653 Java GSS-API Update August 2009

9. Security Considerations

 The Java language security model allows platform providers to have
 policy-based fine-grained access control over any resource that an
 application wants.  When using a Java security manager (such as, but
 not limited to, the case of applets running in browsers) the
 application code is in a sandbox by default.
 Administrators of the platform JRE determine what permissions, if
 any, are to be given to source from different codebases.  Thus, the
 administrator has to be aware of any special requirements that the
 GSS provider might have for system resources.  For instance, a
 Kerberos provider might wish to make a network connection to the Key
 Distribution Center (KDC) to obtain initial credentials.  This would
 not be allowed under the sandbox unless the administrator had granted
 permissions for this.  Also, note that this granting and checking of
 permissions happens transparently to the application and is outside
 the scope of this document.
 The Java language allows administrators to pre-configure a list of
 security service providers in the <JRE>/lib/security/java.security
 file.  At runtime, the system approaches these providers in order of
 preference when looking for security related services.  Applications
 have a means to modify this list through methods in the "Security"
 class in the "java.security" package.  However, since these
 modifications would be visible in the entire Java Virtual Machine
 (JVM) and thus affect all code executing in it, this operation is not
 available in the sandbox and requires special permissions to perform.
 Thus, when a GSS application has special needs that are met by a
 particular security provider, it has two choices:
 1) To install the provider on a JVM-wide basis using the
    java.security.Security class and then depend on the system to find
    the right provider automatically when the need arises.  (This
    would require the application to be granted a "insertProvider
    SecurityPermission".)
 2) To pass an instance of the provider to the local instance of
    GSSManager so that only factory calls going through that
    GSSManager use the desired provider.  (This would not require any
    permissions.)

10. Acknowledgments

 This proposed API leverages earlier work performed by the IETF's CAT
 WG as outlined in both RFC 2743 [GSSAPIv2-UPDATE] and RFC 2744
 [GSSAPI-Cbind].  Many conceptual definitions, implementation
 directions, and explanations have been included from these documents.

Upadhyay & Malkani Standards Track [Page 96] RFC 5653 Java GSS-API Update August 2009

 We would like to thank Mike Eisler, Lin Ling, Ram Marti, Michael
 Saltz, and other members of Sun's development team for their helpful
 input, comments, and suggestions.
 We would also like to thank Joe Salowey, and Michael Smith for many
 insightful ideas and suggestions that have contributed to this
 document.

11. Changes since RFC 2853

 This document has following changes:
 1) Major GSS Status Code Constant Values
    RFC 2853 listed all the GSS status code values in two different
    sections: section 4.12.1 defined numeric values for them, and
    section 6.8.1 defined them as static constants in the GSSException
    class without assigning any values.  Due to an inconsistent
    ordering between these two sections, all of the GSS major status
    codes resulted in misalignment, and a subsequent disagreement
    between deployed implementations.
    This document defines the numeric values of the GSS status codes
    in both sections, while maintaining the original ordering from
    section 6.8.1 of RFC 2853 [RFC2853], and obsoletes the GSS status
    code values defined in section 4.12.1.  The relevant sections in
    this document are sections 5.12.1 and 7.8.1.
 2) GSS Credential Usage Constant Values
    RFC 2853 section 6.3.2 defines static constants for the
    GSSCredential usage flags.  However, the values of these constants
    were not defined anywhere in RFC 2853 [RFC2853].
    This document defines the credential usage values in section
    7.3.2.  The original ordering of these values from section 6.3.2
    of RFC 2853 [RFC2853] is maintained.
 3) GSS Host-Based Service Name
    RFC 2853 [RFC2853], section 6.2.2, defines the static constant for
    the GSS host-based service OID NT_HOSTBASED_SERVICE, using a
    deprecated OID value.
    This document updates the NT_HOSTBASED_SERVICE OID value in
    section 7.2.2 to be consistent with the C-bindings in RFC 2744
    [GSSAPI-Cbind].

Upadhyay & Malkani Standards Track [Page 97] RFC 5653 Java GSS-API Update August 2009

12. References

12.1. Normative References

 [GSSAPI-Cbind]
            Wray, J., "Generic Security Service API Version 2 :
            C-bindings", RFC 2744, January 2000.
 [GSSAPIv2-UPDATE]
            Linn, J., "Generic Security Service Application Program
            Interface Version 2, Update 1", RFC 2743, January 2000.
 [RFC2025]  Adams, C., "The Simple Public-Key GSS-API Mechanism
            (SPKM)", RFC 2025, October 1996.
 [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119, March 1997.
 [RFC2853]  Kabat, J. and M. Upadhyay, "Generic Security Service API
            Version 2 : Java Bindings", RFC 2853, June 2000.
 [RFC4121]  Zhu, L., Jaganathan, K., and S. Hartman, "The Kerberos
            Version 5 Generic Security Service Application Program
            Interface (GSS-API) Mechanism: Version 2", RFC 4121, July
            2005.

12.2. Informative References

 [JLS]      Gosling, J., Joy, B., Steele, G., and G. Bracha "The Java
            Language Specification", Third Edition,
            http://java.sun.com/docs/books/jls/.

Upadhyay & Malkani Standards Track [Page 98] RFC 5653 Java GSS-API Update August 2009

Authors' Addresses

 Mayank D. Upadhyay
 Google Inc.
 1600 Amphitheatre Parkway
 Mountain View, CA  94043
 USA
 EMail: m.d.upadhyay+ietf@gmail.com
 Seema Malkani
 ActivIdentity Corp.
 6623 Dumbarton Circle
 Fremont, California 94555
 USA
 EMail: Seema.Malkani@gmail.com

Upadhyay & Malkani Standards Track [Page 99]

/data/webs/external/dokuwiki/data/pages/rfc/rfc5653.txt · Last modified: 2009/08/11 22:23 (external edit)