CAS is an authentication system originally created by Yale University to provide a trusted way for an application to authenticate a user. CAS provides enterprise single sign on service: CAS Downloads * An open and well-documented protocol * An open-source Java server component * A library of clients for Java, .Net, PHP, Perl, Apache, uPortal, and others * Integrates with uPortal, BlueSocket, TikiWiki, Mule, Liferay, Moodle and others * Community documentation and implementation support * An extensive community of adopters