Re:Luhn Algorithm for validating credit cards
by dasp on Friday July 03, 2015 @07:59AM
(#9824942)
The first time I've seen the Luhn algorithm was on a compromised web server. The cracker has put several fake ebay login/registration pages, as well as a couple of Javascript files.
The pages were obviously intended to be used for phishing. However, what really made me go "wow" was the extra mile they went: one of the Javascript files contained methods that took the credit card number from the fake registration page and checked its validity w/ the Luhn algorithm before emailing it to a random email address. If the number was invalid, the user got an error and they forced him to re-enter.
I didn't know about the algorithm at the time (this was around 2005), so I was a bit baffled what the heck they are trying to do.
The pages were obviously intended to be used for phishing. However, what really made me go "wow" was the extra mile they went: one of the Javascript files contained methods that took the credit card number from the fake registration page and checked its validity w/ the Luhn algorithm before emailing it to a random email address. If the number was invalid, the user got an error and they forced him to re-enter.
I didn't know about the algorithm at the time (this was around 2005), so I was a bit baffled what the heck they are trying to do.