Single Login

http://www.umich.edu/~umweb/software/cosign/overview.html

cosign is a Web single sign on system that allows users to authenticate once per session and access any protected Web resources at the institution. If used, passwords are sent only to a single, central URL. Sessions have both idle and hard timeouts, and users can logout of all protected services by visiting a single URL. The use of public key cryptography ensures that a compromise of a protected Web server has no impact on the security of other participating servers.
found: http://securityfocus.com/tools/3162