Patent ID: 8417219

Claim:
A method for performing pre-authentication by a mobile terminal before a handover to a target network in order to quickly perform an Inter-Radio Access Technology (Inter-RAT) handover, the method comprising: transmitting an extensible authentication protocol (EAP) pre-authentication start message including mobile terminal information needed for the pre-authentication to a target authentication server via a serving authentication server, wherein the mobile terminal information includes specific information defining the pre-authentication, an identifier of a serving network, an identifier of the serving authentication server, an identifier of the target network, an identifier of the mobile terminal, and a Media Access Control (MAC) address of the mobile terminal; receiving an EAP pre-authentication request message including first security-associated information of the target network from the target authentication server via the serving authentication server, wherein the first security-associated information is based on the mobile terminal information, and wherein the first security-associated information includes a random number (RAND), an authentication token (AUTN), a message authentication code (MAC), and protected pseudonym information; transmitting an EAP pre-authentication request message including second security-associated information generated using the first security-associated information to the target authentication server via the serving authentication server, wherein the second security-associated information is used by the mobile terminal in the target network; and performing the handover to the target network after completion of the pre-authentication by the target authentication server based on the second security-associated information.