Here's the deal: it is a mod-10 formula... based on the length... so on some it is odd digit math, others it is even...
3xxx - AMEX 4xxx - Visa 5xxx - MasterCard 6xxx - Discover the formula is widely available and hasn't changed in 20 years.. it is 2nd grade math.... -p -----Original Message----- From: Jim McAtee [mailto:[EMAIL PROTECTED]] Sent: Wednesday, November 28, 2001 23:16 To: CF-Talk Subject: Credit Card Validation Can anyone point me toward an authoritative source for the algorithms used to validate credit card numbers and to identify card types based on the card number? There are numerouse code examples to be found on the web, in various languages (but with significant differences in both the checksum validation and in the card identification). I'd like to find a source that I can have a little more confidence in. Thanks, Jim ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Get the mailserver that powers this list at http://www.coolfusion.com FAQ: http://www.thenetprofits.co.uk/coldfusion/faq Archives: http://www.mail-archive.com/[email protected]/ Unsubscribe: http://www.houseoffusion.com/index.cfm?sidebar=lists
