CAS stands for Central Authentication Service. It's a enterprise authentication system used by many Ryerson web applications to verify a user’s identity. It controls the login process to my.ryerson.ca, Google Apps at Ryerson, and other services.
CAS supports Single Sign On (SSO). SSO is a session/user authentication process that allows a user to provide his or her credentials once, in order to access multiple applications. It authenticates the user to access all the CAS-ified applications that he or she has been authorized to.
When a user needs to access a Ryerson web application that requires authentication and has been CAS-ified, the web application will send the user to CAS in order to find out who the user is. CAS will ask for the user’s my.ryerson username and password and check it against Ryerson’s Identity Management System. When the username and password are verified, CAS will tell the web application who the user is.
If you have an application that you want to authenticate through the CAS system, you should submit your request using the CAS Service Request Form.