| 摘要 |
A method for monitoring an execution of a sequence of instructions of a data processing program (PR) in a security module (SM) associated to a multimedia unit (MU) connected to a managing center (MC) supplying control messages (ECM, EMM) authorizing the multimedia unit (MU) to access broadcast audio video content data streams. The security module (SM) comprises at least one processor (CPU) executing the data processing program instructions, a memory (M), and a monitoring module (MM) for analyzing the instructions before execution by the processor (CPU). The managing center (MC) comprises a security module emulator (EM) generating reference data sets (REF) by executing a sequence of instructions induced by data of a given control message (ECM, EMM) in the data processing program (PR). The reference data sets (REF) are appended to control messages (ECM, EMM) sent to the security module (SM) for verification. The monitoring module (MM) analyses a sequence of instructions of the data processing program (PR) for determining a check data set (CD) which is compared with a reference data set (REF) received from the control messages (ECM, EMM). When the reference data set (REF) matches with the check data set (CD), the data processing program (PR) continues its execution. Otherwise, the monitoring module (MM) sends an instruction (INT) to the processor (CPU) preventing further processing of the control messages (ECM, EMM) by the security module (SM). |
