It may also involve a back-end service, such as a database server, that does not have its own HTTP interface but communicates with a web application.
CAS validates the client's authenticity, usually by checking a username and password against a database (such as Kerberos, LDAP or Active Directory).
If the authentication succeeds, CAS returns the client to the application, passing along a service ticket.
A cooperating back-end service, like a database or mail server, can participate in CAS, validating the authenticity of users via information it receives from web applications.
In December 2004, CAS became a project of the Java in Administration Special Interest Group (JASIG), which is as of 2008 responsible for its maintenance and development.