Interfacing to Other Authentication Systems
There are many web-based authentication systems. Some of these systems can or must delegate actually identifying people to other systems. Delegating to Raven would allow members of the University to dispence with yet another password.
Shibboleth
Shibboleth is a Federated Security Infrastructure being developed in the USA and increasingly being considered for use within .ac.uk. Federated Security: The Shibboleth Approach is a good introduction.
Part 3 of "Web Services Security", Bilal Siddiqui, talks about SAML (the Security Assertions Markup Language) which is what underpins Shibboleth. Part 1 Part 2 Part 3 Part 4
OpenID
OpenID is a decentralized identity system that appears to have connections with the LiveJournal community. At least one member of the University has constructed a bridge between Raven and OpenID.