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“Yes” cards were a threat but they had two problems - they could only work with static data authentication (which has hopefully been phased out by now) and the
by Nursie 5y ago
“Yes” cards were a threat but they had two problems - they could only work with static data authentication (which has hopefully been phased out by now) and the terminal itself would contain 1-in-n goes online regardless checks, plus limits for offline transactions.
An oversight in the EMV specs certainly, but not a showstopper.
IIRC I made one of these with an ICC Solutions programmable card about 20 years ago (in the context of building an EMV system at the time)
I love the story there though :)
- kappuchino 5y agoHey, you would not believe that if I had no proof ;-) ... but the true cause of the "yes cards" was some kind of glitch on side of visa/mastercard AND the banks. So at that time some banks had not even issued chip cards to their customers. If you "cloned"/transformed the data from the magstripe to the chip and tweaked a few bits ... well, that confused the system and defaulted to "yes" due visa/mastercards setup/fallback. Naturally, this problem has sloved itself by now.