The invention aims to provide a method and a system on chip able to detect at once hardware and software errors to prevent manipulations for retrieving cryptographic keys, inserting or suppressing instructions to bypass security processes, modifying programs or memory content etc. The system on chip comprises a core including at least two processors, registers, and a data consistency check module. The core is connected to at least one set of memories containing zones for instructions of a first program and of a second program, said instructions being to be executed respectively by the first and second processor, which respectively produce and store result data into the registers and the memories. The data consistency check module is configured to verify conformity of the produced result data by comparing a test result obtained by carrying out a predetermined function F over one of the first or second result data with the corresponding second or first result data and to continue execution of instructions of each program when the comparison is successful, or stop execution when the comparison shows an error.