At Indiana University, the CAS (Central Authentication Service) login service allows you to access multiple IU computing systems after entering your IU username and passphrase only once on a central authentication system. This is often referred to as single sign-on.

IU students, faculty, and staff authenticate through CAS using their IU usernames and passphrases. Individuals who are not officially affiliated with IU can use their IU Guest account or IU Extranet account credentials to authenticate through CAS for access to a limited number of IU services.

CAS currently supports several IU web applications, including One.IU, Time, PeopleSoft, HRMS (payroll), and the employee Paid Time Off (ePTO) system. In the future, other IU systems will use CAS as well.

You will be automatically redirected to the CAS login screen when you access one of the supported systems, unless you have already authenticated to CAS during your session. You can also reach the CAS login screen directly at

CAS currently supports three types of authentication: Active Directory, Duo, and Guest. CAS clients can be deployed on a combination of platforms including Windows, Linux, and both Apache and IIS. CAS supports a variety of tools and languages.

While CAS authentication will only return a username, you can use that username to query ADS and retrieve more information. See Query ADS using LDAP.


To stay informed or provide feedback about CAS, or to ask questions about developing with it, use the cas-discuss-l mailing list. To subscribe, send email to

This is document akui in the Knowledge Base.
Last modified on 2019-03-20 14:47:15.

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