PROTECTING SYSTEM OF IDENTIFICATION NUMBER

摘要

PURPOSE:To prevent an identification number from alter and a terminal equipment from illegal operation by executing specific arithmetic for a sent identification number and comparing the operated result with a sent operated result to discriminate the legality of the identification number CONSTITUTION:The identification number of the terminal equipment is stored in a ROM42 of an IC card reader/writer 28 and the identification number is inputted to the IC card. The identification number is operated on the basis of a secret program in the IC card and then the operated result and the identification number itself are transmitted to a center processor through a CPU21 from a telephone set 30 through a line 13. The processor operates the sent identification number on the basis of the same secret program stored in the user's IC card. When the operated result coincides with the sent operated result, the legality of the terminal equipment is confirmed.