One embodiment of the present invention provides a system that facilitates determining an identity of a third-party user in a Security Assertion Markup Language (SAML) implementation of a web-service. During operation, the system receives an SAML token profile web service request from the third-party user at the web-service. The system also receives a digital certificate designated by the SAML token profile web service request from the third-party user at the web-service. Next, the system analyzes the digital certificate to identify a third-party associated with the third-party user. The system then determines if the third-party is a trusted party. Next, the system receives one or more attributes associated with the third-party user at the web-service. The system then uses the attributes to identify the third-party user. Finally, the system performs a lookup in a user map to determine a user account that is associated with the third-party user.