Generic Security Services Application Programming Interface: Difference between revisions

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{{Short description|Application programming interface}}

{{more footnotes|date=October 2013}}

The '''Generic Security Service Application Programming Interface''' ('''GSSAPI''', also '''GSS-API''') is an [[application programming interface]] for programs to access [[security]] services.

The GSSAPI is an [[IETF]] standard that addresses the problem of many similar but incompatible security services in use {{Asof|2005|lc=y}}.

== Operation ==

The '''Generic Security Services Application Program Interface''' ('''GSSAPI''', also '''GSS-API''') is an [[application programming interface]] for programs to access [[security]] services.

The GSSAPI, by itself, does not provide any security. Instead, security-service vendors provide GSSAPI ''implementations'' - usually in the form of [[Library (computer science)|libraries]] installed with their security software. These libraries present a GSSAPI-compatible interface to application writers who can write their application to use only the [[Standardization|vendor-independent]] GSSAPI.

The GSSAPI is an [[IETF]] standard that addresses the problem that there are many similar but incompatible security services in use today.

== How it works ==

The GSSAPI, by itself, does not provide any security.

Instead, security service vendors provide GSSAPI ''implementations'' usually in the form of [[Library (computer science)|libraries]] installed with their security software. These libraries present a GSSAPI-compatible interface to

application writers who can write their application to use only the [[Standardization|vendor-independent]] GSSAPI.

If the security implementation ever needs replacing, the application need not be rewritten.

The definitive feature of GSSAPI-using softwareapplications is itsthe exchange of opaque messages (''tokens'') which hide the implementation detail from the higher-level application.

The client and server sides of the application are written to convey the tokens given to them by

which hide the implementation detail from the higher level applications.

The client and server sides of the application are written to first convey the tokens given to them by

their respective GSSAPI implementations.

TheseGSSAPI tokens can beusually exchangedtravel onover an insecure network becauseas theythe aremechanisms guaranteedprovide toinherent bemessage inherently securesecurity.

After somethe numberexchange of tokenssome havenumber beenof exchangedtokens, the GSSAPI implementations at both ends inform their local application that a ''security context'' has beenis established.

Once a security context is established, sensitive application messages can be wrapped (encrypted) by the GSSAPI implementation for secure communication between client and server.

Typical protections guaranteed by GSSAPI wrapping include [[confidentiality]] (secrecy) and [[Data integrity|integrity]] (authenticity). The GSSAPI can also provide local guarantees about the identity of the remote user or remote host.

AThe sampleGSSAPI ofdescribes some of theabout 45 standard procedure calls. ofSignificant the GSSAPIones include:

*; ''GSS_Acquire_cred'' -: obtainsObtains the user's loginidentity proof, often a secret cryptographic key

*; ''GSS_Import_name'': - convertsConverts a typed username or hostname into a form that identifies a securablesecurity entity

*; ''GSS_Init_sec_context'': - generatesGenerates a newclient token to send to the server, usually a challenge

*; ''GSS_Accept_sec_context'': - processProcesses a token generated byfrom '''GSS_Init_sec_context''' and can generate a newresponse token to send backreturn

*; ''GSS_Wrap'': - convertConverts application data into a secure message token (typically encryptencrypted)

*; ''GSS_Unwrap'': - convertConverts a secure message token back tointo application data

The GSSAPI is standardized for the [[C (programming language)|C]] (RFC 2744) language. [[Java (programming language)|Java]] implements the GSSAPI<ref>{{cite web

The GSSAPI has been standardised for the

| url=https://jcp.org/aboutJava/communityprocess/review/jsr072/index.html

[[C (programming language)|C]] and [[Java (programming language)|Java]] languages.

| title=JSR-000072 Generic Security Services API Specification 0.1

A standard for [[C Sharp|C♯]] is forthcoming.

| date=2001-06-15

| access-date=2015-10-07}}</ref>

as JGSS,<ref>{{cite book

| last1 = Schönefeld

| first1 = Marc

| title = Refactoring of Security Antipatterns in Distributed Java Components

| url = https://books.google.com/books?id=cUWFz3oZLyAC

| series = Schriften aus der Fakultät Wirtschaftsinformatik und Angewandte Informatik der Otto-Friedrich-Universität Bamberg

| volume = 5

| publisher = University of Bamberg Press

| date = 2010

| page = 179

| access-date = 2015-10-07

| quote = JGSS is the JAVA implementation of the GSSAPI.

| isbn = 9783923507689}}</ref>

the Java Generic Security Services Application Program Interface.<ref>{{cite book

| last1 = Fisher

| first1 = Marina

| last2 = Sharma

| first2 = Sonu

| last3 = Lai

| first3 = Ray

| last4 = Moroney

| first4 = Laurence

| title = Java EE and .NET Interoperability: Integration Strategies, Patterns, and Best Practices

| url = https://books.google.com/books?id=CXnCJhrB3g4C

| publisher = Prentice Hall Professional

| date = 2006

| access-date = 2015-10-07

| quote = Java Generic Security Services Application Program Interface (JGSS) API for uniform access to security services atop a variety of underlying security mechanism, including Kerberos, which are building blocks for single sign-on and data encryption.

| isbn = 9780132715706}}</ref>

<!-- A standard for [[C Sharp|C#]] is forthcoming. C# work appears to have perished -->

Some limitations of GSSAPI are:

Limitations of the GSSAPI include that it standardizes only [[authentication]], and not [[authorization]], and that it assumes a [[client-server]] architecture.

# standardizing only [[authentication]], rather not [[authorization]] too;

# assuming a [[client–server]] architecture.

Anticipating new security mechanisms, the GSSAPI includes a negotiating ''pseudo mechanism'', [[SPNEGO]], that can discover and use new mechanisms not present when the original application was built.

When the remote GSSAPI implementation's capabilities are unknown, the local GSSAPI implementation can negotiate a common mechanism by using [[SPNEGO]].

== Relationship to Kerberos ==

The dominant GSSAPI mechanism implementation in use is [[Kerberos (protocol)|Kerberos]].

<!-- Ref: MS Active Directory uses SSPI, MIT and Heimdal provide gssapi -->

This can be explained byUnlike the observation thatGSSAPI, the Kerberos API ishas not been unstandardizedstandardized

and thatvarious thereexisting areimplementations varioususe incompatible APIs for its implementations.

The GSSAPI allows Kerberos implementations to be API compatible.

== Related technologies ==

* [[Remote Authentication Dial In User Service|RADIUS]]

* [[Simple Authentication and Security Layer|SASL]]

* [[Secure Sockets Layer|TLS]]

* [[Security Support Provider Interface|SSPI]]

* [[SPNEGO]]

* [[RPCSEC GSS]]

== CompetingKey technologiesconcepts ==

;Name :A binary string that labels a [[security principal]] (i.e., user or service program) - see [[access control]] and [[identity (object-oriented programming)|identity]]. For example, [[Kerberos (protocol)|Kerberos]] uses names like ''user@REALM'' for users and ''service/hostname@REALM'' for programs.

[[RADIUS]],

;[[Credential]]s :Information that proves an identity; used by an entity to act as the named principal. Credentials typically involve a secret cryptographic key.

[[SASL]],

;Context :The state of one end of the authenticating/authenticated [[protocol (computing)|protocol]]. May provide message protection services, which can be used to compose a [[secure channel]].

[[Secure Sockets Layer|SSL]].

;Tokens :Opaque messages exchanged either as part of the initial authentication protocol (context-level tokens), or as part of a protected communication (per-message tokens)

;Mechanism :An underlying GSSAPI implementation that provides actual names, tokens and credentials. Known mechanisms include [[Kerberos (protocol)|Kerberos]], [[NTLM]], [[Distributed Computing Environment]] (DCE), SESAME, [[SPKM]], LIPKEY.

;Initiator/acceptor :The peer that sends the first token is the initiator; the other is the acceptor. Generally, the client program is the initiator while the server is the acceptor.

== History ==

The SSPI API found in [[Microsoft Windows]] is a competing (and slightly different) implementation of the same logical model behind GSSAPI (RFC 2743). The extension to RFC 2743 that stands out the most is the capability to turn client credentials into a security subject (a token, in Windows parlance) that the server can temporarily use to impersonate the client.

* July 1991: IETF Common Authentication Technology (CAT) Working Group meets in Atlanta, led by John Linn

* September 1993: GSSAPI version 1 (RFC 1508, RFC 1509)

* May 1995: Windows NT 3.51 released, includes SSPI

* June 1996: Kerberos mechanism for GSSAPI (RFC 1964)

* January 1997: GSSAPI version 2 (RFC 2078)

* October 1997: SASL published, includes GSSAPI mechanism (RFC 2222)

* January 2000: GSSAPI version 2 update 1 (RFC 2743, RFC 2744)

* August 2004: KITTEN working group meets to continue CAT activities

* May 2006: Secure Shell use of GSSAPI standardised (RFC 4462)

==See also==

== Key concepts of the GSSAPI ==

*[[PKCS 11|PKCS #11]]

;Name :A binary string that labels a security principal (i.e. user or service program) - see [[access control]] and [[identity]]. For example, [[Kerberos (protocol)|Kerberos]] uses names like ''user@REALM'' for users and ''service/hostname@REALM'' for programs.

;[[Credentials]] :Information that proves a name. May be used by an entity to act as that principal. Typically this is a secret cryptographic key.

;Context :The state of one end of the authenticating/authenticated [[protocol (computing)|protocol]]. Provides a [[secure channel]] when established.

;Tokens :Opaque messages exchanged as part of the initial authentication protocol.

;Mechanism :An underlying GSSAPI implementation that provides actual names, tokens and credentials. Known mechanisms include [[Kerberos (protocol)|Kerberos]], [[NTLM]],

;Initiator/acceptor :The peer that sends the first token is the initiator; the other the acceptor. Generally, the client program is the initiator while the server is the acceptor.

== References ==

{{Reflist}}

== External links ==

* {{IETF RFC|2743|link=no}} The Generic Security Service API Version 2 update 1

* RFC 1509, RFC 1964, and RFC 2743.

* {{IETF RFC|2744|link=no}} The Generic Security Service API Version 2: C-Bindings

* [http://www.ietf.org/html.charters/kitten-charter.html Kitten working group - next generation GSS-API]

* {{IETF RFC|1964|link=no}} The Kerberos 5 GSS-API mechanism

* {{IETF RFC|4121|link=no}} The Kerberos 5 GSS-API mechanism: Version 2

* {{IETF RFC|4178|link=no}} The Simple and Protected GSS-API Negotiation Mechanism (SPNEGO)

* {{IETF RFC|2025|link=no}} The Simple Public-Key GSS-API Mechanism (SPKM)

* {{IETF RFC|2847|link=no}} LIPKEY - A Low Infrastructure Public Key Mechanism Using SPKM

* {{cite web

| url=https://datatracker.ietf.org/wg/kitten/charter/

| title=Common Authentication Technology Next Generation (kitten)

| date=September 2013

| publisher=[[Internet Engineering Task Force]]}}

* {{cite web

| url=https://docs.oracle.com/cd/E19683-01/816-1331/

| title=GSS-API Programming Guide — Sun Solaris 9

| date=2002

| author=Sun Microsystems

| author-link=Sun Microsystems

| publisher=[[Oracle Corporation]]}}

* {{cite web

| url=https://docs.oracle.com/cd/E37838_01/html/E61050/secov-gss.html

| title=Writing Applications That Use GSS-API — Oracle Solaris 11.4, Developer's Guide to Security

| date=2020

| author=Oracle Corporation

| author-link=Oracle Corporation}}

{{Authentication APIs}}

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[[Category:Operating system security]]

[[Category:Internet standardsStandards]]