Page History

...

According to the SAML specification a Principal is a system entity whose identity can be authenticated. An Identity Provider is a service provider that creates, maintains, and manages identity information for principals [ and provides principal authentication to other service providers (not to get too entangled)]; .

A principal can have any number of attributes; identity is just one of them; Other attributes are groups, locations, etc; Logically these values are asserted by the Attribute Authority based on the identity; In practice Identity Provider and the Attribute Authority are usually collocated (although in complex SOA models providers can form a federation for identities and attributes);

...