| 摘要 |
The transaction card and method are used for securing a transaction conducted by mean of a credit card, a debit card, a security card or any other card including information to be read by a magnetic card reader. The card is provided with a counter which increments by 1 or any other number each time the card is activated. This counter value is used with a key string in a cryptographic algorithm to produce a signature. The resulting data stream is then transmitted to a computer. The computer may be one of the servers of a bank, a credit card provider, a security department, etc. Once the data stream is received, the computer finds the record of the card or cardholder using the identification number or any other number, then determines with the signature if the transaction is legitimate or not. The counter value is also verified. Accordingly, if the counter value of the current transaction is below or equal to that of the last transaction, this means that someone is trying to use the same data stream twice or an expired data stream. Any suspect transaction would be denied and the standard protocol in case of the detection of a fraud initiated.
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