Recently, many application services, especially financial services, require more reliable or combined authentication methods such as multifactor authentication due to the increase in identity (ID) theft. For example, one-time password authentication and other new authentication methods are used instead of the traditional password-based authentication.

The combinations of authentication methods provide multiple identity service providers (IdSPs) the ability to enhance the assurance of authentication. Recommendation ITU-T X.1154 provides the general framework of combined authentication in multiple IdSP environments for a service provider. In this Recommendation, three types of combined authentication methods are considered: multifactor authentication, multi-method authentication and multiple authentications.

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.