Credit cards

Here’s the algorithm for checksumming a credit card number, plus information on what all the fields are.

But you can checksum the numbers all you like, if the signature doesn’t match the transaction never happened.

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1 thought on “Credit cards

  1. glen

    I love that prank. Amazing how much you can get away with. I heard recently that they’re planning to replace the signature with a PIN. Probably better security.

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