| 摘要 |
PROBLEM TO BE SOLVED: To provide one type of an identifying method for a credit card, an ID card or a personal identification number user in order to prevent fabrication, duplication and appropriation or later denial of a true card holder himself/herself by making the true card holder acquire one key number before using a card and making an authentication unit perform contrast. SOLUTION: The card holder goes into the computer of the authentication unit by a private telephone set on a number display through a communication network, subsequently acquires a random random number issued by the computer as the key number by inputting the personal identification number, preserves the key number after a computer enciphers the key number, transmits a card number and the enciphered key number to the computer of the authentication unit to perform contrast when the card holder does shopping and performs mail-order and an electronic commercial transaction by the card, completes the transaction where there is no mistake, and immediately discards the key number after contrasting the key number one time regardless of the correctness/incorrectness of the key number. The credit card is decided to be completely invalid when the key number of the card does not exist in the computer, and the loss of rights and interests is prevented from being formed by the duplication, fabrication or copying of the credit card or in such a manner that the card holder later denies the transaction. |
