A processing system is disclosed. The system comprises: a processor; memory adapted to store data for use by the processor; a verification unit adapted to identify a trusted region of the memory and to process data stored in the trusted memory region in accordance with a predetermined verification algorithm to verify the trusted status of the trusted memory region; and a memory access control unit adapted to control access of the processing unit to data stored in the trusted memory region based on whether its trusted status is verified by the verification unit.
