Credit Card Number Validation Using Mod10 (Modulus 10)
Saturday, August 25th, 2007When someone submits a credit card number to your PHP Website, you can validate if the number has the correct format for each credit card company. The Modulus 10 calculation with a few checks can tell you which company issued the card, if the number is in the correct format, but not if there are funds on the card or if it is stolen. Reversing the mod10 calculations can create valid credit card numbers that can pass the mod10 checks, but without funds, they could only fool systems that approve cards by format and value without a back-end check at the bank. (more…)
