authentic or not the functions of these two semiconductor devices 30 and 34 can be compared to the relationship between a lock and a key accordingly in the following description the semiconductor device 30 is called a lock device and the semiconductor device 34 is called a key device in reference to fig3 the lock device 30 is composed for example of a 4 bit microprocessor comprising a cpu 30a as a data processing means and a rom 30b and ram 30c as semiconductor memories the rom 30b stores an operating program for the cpu 30a and two arithmetic routines are contained in this operating program thus a plurality of formulas and data of random numbers for arithmetic computation according to such formulas are contained in one operating program the operating program also includes a program routine for comparing the computation result of the lock device 30 with the result computed by the key device 34 and vice versa and for determining whether the results agree the cpu 30a of lock device 30 functions as a determining means when these comparison and determination routines are executed furthermore a control program routine for controlling reset or release of reset of the main unit 12 based on the results of the comparison and determination program routines is contained in the operating program.