CREDIT CARD USING COUNTERFEIT PREVENTIVE CODE, OR CASH CARD COUNTERFEIT PREVENTIVE SYSTEM, AND COUNTERFEIT PREVENTIVE METHOD

摘要

A system for preventing a credit card or the like from being counterfeited by using counterfeit preventive code, where so as to prevent damage from counterfeit of a credit card or the like, a counterfeit preventive code is updated irrespective of whether the credit card is used or not and the card owner can initiatively update the counterfeit preventive code. A counterfeit preventive code is stored in a card medium and also in a client DB of a card company host. The counterfeit preventive code in the client DB is periodically updated. When the card owner requests check of the code through, e.g., an ATM, the card owner is authenticated by means of a password if the counterfeit preventive code in the card medium does not match the one in the client DB. If the card owner is successfully authenticated, the counterfeit preventive code in the client DB is overwritten in the card medium. The counterfeit preventive code can be updated in response to request of the card owner. When a sales approval request is received from a CAT terminal, the matching of the counterfeit preventive codes is confirmed, and an approval message is sent as a reply.