So stop handing out your permanent address. Start handing out hotel keys. Use it, verify it, and
By using discardable numbers, you stop treating online security like a fortress (trying to keep the bad guys out) and start treating it like a spy movie (using a key that self-destructs after every use). If a merchant stores your real credit card number, that database will eventually be leaked. It is a statistical certainty.
But what if you could stop holding your breath? What if you could hand over a credit card number that works just once —and then vanishes into thin air?