Security Assertion Markup Language (SAML) is an XML-based data format used for security assertions. Service providers (SP) will typically allow an entity (e.g., a user, administrator, or enterprise) to configure the system for SAML delegation to an identity provider (IdP). For an enterprise, instead of making employees maintain multiple authentication credentials for internal enterprise system and for the service provider, the service provider can use the IdP so only one set of credentials may be used by an employee. When the user attempts to use a service of the service provider, the SP can request to authenticate the user through the IdP. Based on an identity assertion response of the IdP, the SP can make an access control decision. Many service providers only allow a single IdP service to be configured. However, such implementation limits authentication security to the security level of the IdP. Thus, there is a need in the authentication and authorization field to create a new and useful system and method for proxying authentication providers. This invention provides such a new and useful system and method.