Jennifer's OpenID Sequence Diagram

There are a series of redirects. Depending on whether or not a site is trusted by the user, a user may or may not be prompted to authorize the passing of credentials and optionally an attribute exchange (via the the simple registration extension) between the site and the OpenID Server.

These redirects are visualized in Jennifer's sequence diagram.

A good narrative to go with the diagram can be found in the overview of the Python OpenID Library consumer module.