| 摘要 |
PURPOSE:To furthermore improve the security level of a card by repeating the reading and ciphering of a random pattern formed on the card. CONSTITUTION:At the time of writing identification (ID) data on a card 21, data D0 on a reference position P0 of a random pattern 23 are read out to read out the data D1 of a random pattern for the ciphered data P1 of the data D0. The data D1 are ciphered, a position PMM2 to be successively scanned is selected and data D2 on the position are found out. The operation is continuously repeated by the prescribed number of times and ID data Di are obtained as a different value in each card. At the time of reading processing, the data Di are read out and compared with finally read data D, and when both the values match with each other, the validity of the card 21 is decided and transaction processing is executed. At the time of unmatch, NG processing is executed. |
