I need to generate credit card surrogates (tokens) that are format preserving.
- by jammer59
For an eCommerce application I need to take a credit card and use the real card for passing through to a payment gateway but I need to store, and return to the transaction initiator, a surrogate that is format preserving. Specifically, this means:
1) The number of digits in the surrogate is the same as the real card number (PAN).
2) The issuer type part of the card -- the initial 1,2 or 4 digits remains the same in the surrogate as in the original PAN.
3) The final 4 digits of the surrogate remain the same (for customer service purposes.)
4) The surrogate passes the Luhn mod10 check for a syntactially valid credit card.
I can readily handle requirements 1-3 but #4 has me completely stumped! The final implementation will be either t-sql or c#.
Any ideas?
