Abstract: A method for executing a program on a data processing device, the method comprising storing multiple program instructions and data to be processed by a processor of the data processing device in one or more memories of the data processing device; receiving, from an external data processing device, a reference value for a check of the multiple program instructions; computing a check value from the multiple program instructions for the check by way of the data processing device when the program instructions are loaded from the one or more memories into an instruction buffer memory of the data processing device or by way of read access to the instruction buffer memory after the program instructions have been loaded into the instruction buffer memory from the one or more memories; and executing at least some of the program instructions if the check value matches the received reference value.