Patent ID: 8275355

Claim:
A method for an application server in a visited network to establish a security association with a user comprising the steps of: receiving, by the application server in the visited network, a service request message from the roaming user, said service request message containing a Bootstrapping—Transaction Identifier (B-TID), the B-TID being assigned to the roaming user by a Bootstrapping Server Function (BSF) based upon a mutual authentication of the roaming user with the BSF that performs user identity initial verification in a generic authentication architecture in a home network of the roaming user; returning, by the proxy in the visited inquiring, by the application server in the visited network inquiring from a proxy an in the visited network about user's user information of the user associated with the B-TID, the user information comprising user authentication results of the generic authentication architecture in the home network of the user; identifying, by the proxy in the visited network, the home network to which the user belongs according to the B-TID; acquiring, by the proxy in the visited network, the user information associated with the B-TID from the BSF in the home network of the user; network, the acquired user information to the application server; obtaining, by the application server in the visited network the user information of the user comprising the user authentication results of the generic authentication architecture in the home network of the user; and establishing, by the application server in the visited network, a security association with the user according to the user authentication results of the generic authentication architecture in the home network of the user.