Patent ID: 8842832

Claim:
A method of supporting a security for a multicast communication in a mobile station, the method comprising: sharing a multicast authorization key (MAK) with a base station; deriving a prekey based on a first parameter, the first parameter including the MAK and an identifier of a multicast group to which the mobile station belongs; deriving a multicast security key including a multicast traffic encryption key (MTEK) based on a second parameter including the prekey; decrypting a multicast traffic using the multicast security key; receiving a message including information to update of the multicast security key from the base station; and updating the multicast security key based on the information, wherein the information includes an identifier of a multicast group and a flow identifier within the multicast group where the multicast security key is updated, or a connection identifier of the multicast group where the multicast security key is updated.