[thelist] Credit Card Check Digit Validation

Kristy Frey kristenannfrey at yahoo.com
Tue Jan 29 09:52:00 CST 2002

> The mod-10 Luhn test refered to in that article is unlikely to change for a
> long time. Credit card numbers have been constructed on the mod-10 zero
> sum algorithm since VISA was known as BankAmeriCard and
> MasterCard was known as Master-Charge. In addition to websites testing
> for valid number formats, most, if not all, swipe machines also do a "client-
> side" validation before connecting with the call centers to see if the card
> was properly swiped. That test is hard coded on prom chips. This Luhn
> algorithm (patented in 1960) is also used for bar code scanners, it's how
> the clerk knows that the scan didn't take. I've read that phone cards also
> use it.

Thanks Keith!

Do You Yahoo!?
Great stuff seeking new owners in Yahoo! Auctions!

More information about the thelist mailing list