An identity provider (IdP) is a federation partner that vouches for the identity of a user. The Identity Provider authenticates the user and provides an authentication token (that is, information that verifies the authenticity of the user) to the service provider. The identity provider either directly authenticates the user, such as by validating a username and password, or indirectly authenticates the user, such as by validating an assertion about the user’s identity as presented by a separate identity provider. |