Patent ID: 8027666

Claim:
A method for authenticating a terminal subscriber identity module in an IP Multimedia (IM) domain, comprising: sending, by a Serving Call Session Control Function (S-CSCF) in a network, an Authentication Vector (AV) request to a Home Subscriber Server (HSS) set in the network for providing IM domain services, upon receiving an IM domain register request sent from User Equipment (UE); sending, by the HSS, a request message for acquiring the AV to a home device of the UE upon receiving the AV request, wherein the process of sending the request message to the home device of the UE comprises: sending a Authentication Information Message containing the type of requesting node, and an individual sequence number of each UE in the home device of the UE, SQNHE, comprises at least one SQNHE corresponding to at least one type of domain respectively; allocating, by the home device of the UE, a Sequence Number (SQN) for the UE upon receiving the request message, generating an AV based on the SQN, and sending the AV to the HSS, wherein the process of allocating the SQN for the UE comprises: determining, by the home device of the UE, the domain to which the HSS belongs according to the type of requesting node contained in the Sending Authentication Information Message; and allocating the SQN for the domain to which the HSS belongs according to the SQNHE corresponding to the domain to which the HSS belongs; sending, by the HSS, the AV to the S-CSCF; and authenticating, by the S-CSCF, the terminal subscriber identity module of the UE according to the AV.