Central Authentication Service (CAS)

What is CAS?

The Central Authentication Service (CAS) is a single sign-on protocol for the web. Its purpose is to permit a user to access multiple applications while providing their credentials (such as userid and password) only once.

The CAS system uses the IAS LDAP to authenticate users. The same username and password you use to log onto your IAS office computer, IAS email, and IAS VPN will work with the CAS system.

Useful Information

  • When you log out of the CAS, you are logged out of all the applications that use CAS for authentication.
  • When you log out of an application using CAS, that web application will either log you off that application or log you off the application and off the CAS. If you are logged off the CAS, you may need to log back into the other applications using CAS.
  • To force a log out of the CAS: Visit https://cas.ias.edu/cas/logout. You will be logged out of the CAS immediately. This is also useful if you want to log into a system using CAS as a different user name.