Patent ID: 8208636

Claim:
A method for transmitting/receiving encryption information by a broadcast (BCAST) Service Distribution/Adaptation (BSD/A) unit in a mobile broadcast system providing a BCAST service, the method comprising: transmitting a Registration Key Material (RKM) request message for requesting delivery of an RKM for registration of the BCAST service of a terminal to a BCAST Subscription Management (BSM) unit managing subscriber information of the terminal; receiving an RKM request response message from the BSM; transmitting a Long-Term Key Message (LTKM) request message for requesting delivery of an LTKM provided to the terminal during subscription of the BCAST service to the BSM unit; receiving an LTKM request response message from the BSM unit; transmitting a Short-Term Key Message (STKM) request message for acquisition of an STKM including a Traffic Encryption Key (TEK) used for decryption of the BCAST service by the terminal to the BSM unit; and receiving an STKM request response message from the BSM unit, wherein the RKM request message includes an identifier (ID) of the BCAST service, and the RKM request response message includes the ID of the BCAST service and the RKM, wherein the LTKM request message includes the ID of the BCAST service and, and the LTKM request response message includes the ID of the BCAST service and the LTKM, and wherein the STKM request message includes the ID of the BCAST service, and the STKM request response message includes the ID of the BCAST service and the STKM.