Patent ID: 8555064

Claim:
A security processing method of a User Equipment (UE) in a wireless communication system, the method comprising: transmitting a Layer 3 (L3) message comprising a UE security capability to a Mobility Management Entity (MME) and an evolved Node B (eNB); receiving an Access Stratum Security Mode Command (AS SMC) comprising a AS security algorithm selected by the eNB, as a result of verification of the UE security capability and information received from the MME, and a AS Message Authentication Code (MAC); transmitting a AS security mode complete message comprising the AS SMC to the eNB after verification of integrity of the AS SMC using the AS MAC; and transmitting, when receiving a Non Access Stratum (NAS) SMC comprising the UE security capability, a NAS security mode complete message to the MME after verification of integrity of the NAS SMC, wherein the AS security algorithm is selected in order of priority from at least one of a security algorithm allowed for a AS message transmission in the UE security capability from the MME and a security algorithm in a list of previously allowed security algorithms preset by the eNB and matching the UE security capability.