> For the complete documentation index, see [llms.txt](https://docs.chamilo.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.chamilo.org/3.x/administration-guide/admin-guide/authentication/cas.md).

# CAS

> **Status in Chamilo 3.x.** CAS configuration entries (`cas_activate`, `cas_server`, `cas_server_uri`, `cas_port`, `cas_protocol`, `cas_add_user_activate`) still exist in the platform settings as a legacy carry-over from Chamilo 1.x, and CAS still appears as a selectable authentication source on the user form — but there is no CAS authenticator wired into the Chamilo 3.x security pipeline. Logging in through CAS does **not** currently work out of the box. If you need SSO on Chamilo 3.x, use [OAuth2](/3.x/administration-guide/admin-guide/authentication/oauth2.md) (Azure / Keycloak / Generic) or [LDAP](/3.x/administration-guide/admin-guide/authentication/ldap.md) instead.

## What CAS would do (1.x behaviour)

CAS (Central Authentication Service) is a single sign-on protocol commonly used in universities and research institutions. In Chamilo 1.x, clicking "Log in with CAS" would redirect the user to a CAS server, validate the returned ticket, and create or match a local account from CAS attributes.

## Migration note

If you are upgrading a Chamilo 1.x portal that used CAS, plan to re-implement that login flow on top of OAuth2 or LDAP for the time being, until the CAS authenticator is restored in a future 3.x release.