OpenID

From LID Wiki

OpenID is the URL-based authentication and sign-on protocol designed by Brad Fitzpatrick, creator of LiveJournal and a number of other projects. It is based on Diffie-Hellman key exchange and HMACs.

OpenID is fully compatible with the LID architecture, and has been supported as one of the currently two authentication protocols since early in 2006. Since about the same time, both LID and OpenID share Yadis discovery, whose original (and most important) purpose was to make OpenID and LID interoperable.

More information about OpenID can be found at openid.net.