ALTERATION PREVENTION METHOD FOR INFORMATION RECORDED IN CARD, CARD PROVIDED WITH INFORMATION ALTERATION PREVENTION FUNCTION, AND INFORMATION READING AND WRITING APPARATUS USED FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To recognize the alteration of information with extremely high accuracy by reading and collating the detection information of reflected waves or the like at the time of irradiation with electromagnetic waves and the detection information recorded in a card. ;SOLUTION: A prepaid card at the time of shipping is irradiated with weak microwaves from the microwave oscillator of a microwave sensor unit 23 and the detection information (waveform) of reflected microwaves is recorded in a magnetic information recording part. At the time of using the prepaid card for a first time, a microwaveform is detected by the microwave sensor unit 23 and the detection information and waveform information stored in the magnetic information recording part beforehand are compared and collated first. In the case of being judged as the true one, use is permitted. At the time of use, by a magnetic head 21, updated balance information is written in the magnetic information recording part and a hole is formed. Then, the microwaveform is detected by the microwave sensor unit 23 and the information is written in the magnetic information recording part.;COPYRIGHT: (C)1998,JPO