(Greek mythology: the three-headed dog that guarded the gates of Hades). An authentication service that issues a ticket-granting ticket and a one-way hashed session-key (for encryption), stored in a cache. It requires the continuous availability of the kerberos server and synchronised clocks, and can support SSO to other 'kerberised' services. It provides mutual authentication, and many-to-many communications. Created by MIT, used by MS-Windows, Mac, SUN, Linux and others.

Source: http://identityaccessman.blogspot.com/2006/08/identity-dictionary.html