>Ok, so they convert the number to their own "Guest ID". But that would >be a one-time conversion unless they keep a map. And if they have a map, >isn't that keeping the card number?
You don't need to keep a map or the original card number. Just run it through a one way crypt. You don't need to know what the original is, just that the when running the crypt again you get a matching result. The stripe on the credit card has more than just the number encoded so you have a fairly long string you can pass through the algorithm. ( man 3 crypt ; man 5 passwd ) In regards to the data mining tech, the real question is why does anyone think this is news? About 1995, ancient history to many of you, I attended an IBM SP meeting where someone from Fingerhut was describing why they needed a big parallel computer. At the time they had one of the biggest databases in the world. Details on who got what catalogs. What was ordered from each catalog, how they paid, etc etc etc. Catalogs were custom created for small groups of people all over the country based on their purchase history. Very targetted market groups. When someone would call the order center, the sales person popped some piece of info into their screen and they had all the details, including the pages from your current catalog. If you wanted to order a belt, they could tell you that would look great with the boots you bought 3 months ago and would look even better with the shirt on page 37 of your catalog. It was all there. This was long before most people thought of tracking stuff via the central data that all the credit card companies now have. It was long before most customer loyalty cards. It appears to have worked well for them. By having the past sales history and targetted marketing they could get some percentage of added sales by pointing out related merchandise they wanted to move. They wanted to give you that feeling of having your one personal shopper. That they knew you and your tastes. With enough orders they propbably did. --Gene /~\ The ASCII Gene Rackow email: [email protected] \ / Ribbon Campaign Cyber Security Office voice: 630-252-7126 X Against HTML Argonne National Lab / \ Email! 9700 S. Cass Ave. / Argonne, IL 60439 _______________________________________________ Discuss mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
