Unlike the GSSAPI, the Kerberos API has not been standardized and various existing implementations use incompatible APIs. The GSSAPI allows Kerberos implementations to be API compatible. Related technologies RADIUS SASL TLS SSPI SPNEGO RPCSEC GSS Key concepts Name A binary string that labels a security principal (i.e., user or service program) - see access control and identity. For example, Kerberos uses names like user@REALM for users and service/hostname@REALM for programs. Credentials Information that proves an identity; used by an entity to act as the named principal. Credentials typically involve a secret cryptographic key. Context The state of one end of the authenticating/authenticated protocol. May provide message protection services, which can be used to compose a secure channel. 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, 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 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 PKCS #11 References External links The Generic Security Service API Version 2 update 1 The Generic Security Service API Version 2: C-Bindings The Kerberos 5 GSS-API mechanism The Kerberos 5 GSS-API mechanism: Version 2 The Simple and Protected GSS-API Negotiation Mechanism (SPNEGO) The Simple Public-Key GSS-API Mechanism (SPKM) LIPKEY - A Low Infrastructure Public Key Mechanism Using SPKM Operating system security Internet Standards