Patent ID: 8462742

Claim:
A method for optimizing an authentication procedure during inter access system handovers in a heterogeneous network, comprising the steps of: deriving new keys for accessing a new system from most recent system access keys of an existing system; enabling an authentication procedure during a User Equipment (UE) handover from the existing system to the new system by using the most recent system access keys of the existing system; receiving, by the UE, a temporary identification (ID) that is encrypted; decrypting, by the UE, the temporary ID using one of the derived new keys for accessing the new system; and accessing the new system during handover preparation and enabling the UE to perform a fast re-authentication in the new system by using the temporary ID, wherein the UE handover comprises a forward handover that includes sending, by the UE, details of the existing system, which is a previous access system, and retrieving, by the network, a Cypher Key (CK), an Integrity Key (IK), and buffered packets from the previous access system by using the details of the existing system; wherein the UE handover comprises at least one of the following: forward and backward handover between an Integrated Wireless Local Area Network access system (I-WLAN) and a System Architecture Evolution access system (SAE); forward and backward handover between a Universal Mobile Telecommunication System (UMTS) and the SAE; and forward and backward handover between the I-WLAN and the UMTS; and wherein the backward handover from the SAE access system to the I-WLAN comprises checking a Home Subscription Server (HSS), by an Authentication, Authorization and Accounting (AAA) server, to determine whether any AAA is registered, and if not, performing, by the AAA server, a soft registration in which the AAA server generates a Master Session Key (MSK), a Transient Encryption Key (TEK), and an Extended MSK (EMSK) using a Network Access Identifier NAI), the CK and the IK, generates the temporary ID including a pseudonym ID and a fast re-authentication ID, protects the temporary ID using the TEK and sends it to the UE.