Patent ID: 8873757

Claim:
A method of wireless communications, comprising: sending, by a first user equipment (UE), a shared key request using a first non-access stratum (NAS) message to a first mobility management entity (MME), wherein the first NAS message indicates an uplink count value and includes at least a portion of contextual information associated with communication with a second UE; calculating a first UE key based on a MME-first UE key that is shared between the MME and the first UE, the uplink count value, and the at least a portion of the contextual information; receiving a second NAS message, which includes a second UE key calculated by the second UE or by a second MME associated with the second UE, from the first MME; and calculating a final UE key based at least on the first UE key in response to reception of the second NAS message.