An
Identity Provider (IdP), also known as
Identity Assertion Provider, is responsible for (a) providing identifiers for users looking to interact with a system, and (b) asserting to such a system that such an identifier presented by a user is known to the provider, and (c) possibly providing other information about the user that is known to the provider. This may be achieved via an authentication module which verifies a
security token that can be accepted as an alternative to repeatedly explicitly authenticating a user within a security realm.