CAS (Central Authentication Service)
The CAS protocol is a simple and powerful ticket-based protocol. It involves one or many clients and one server. Clients are embedded in CASified applications (called “CAS services”) whereas the CAS server is a standalone component.
The Cas protocol makes it possible to implement the SSO authentication method that allows users to access web applications with a single sign-on.
The specification versions recognized are 3.0.3 and 2.0