scope:

This Recommendation provides the general framework of combined authentication in multiple identity service provider (IdSP) environments for the service provider to achieve combined authentication such as multifactor authentication.

The framework in this Recommendation describes models, basic operations and security requirements for each model component and each message between the model components to maintain an overall level of authentication assurance in situations of a combination of multiple IdSPs.

In addition, the framework also describes models, basic operations and security requirements to support the authentication service that manages a combination of multiple IdSPs.