The "No-Save" Rule (The Most Important Security Feature) Here is why hackers love stealing card numbers but hate CVV2s:
That’s right. When the cashier asks for the "three digits on the back" over the phone, they are asking for a number that the bank cannot verify by looking it up. Instead, the bank runs a on the fly. credit card cvv2 number
The CVV2 is generated by an algorithm that takes your card number, expiration date, and a secret "bank key" (a master encryption key) and spits out a unique 3-4 digit result. When you type it in, the bank’s computer runs the same equation. If your typed number matches the computed result, you pass. If not, you fail. The "No-Save" Rule (The Most Important Security Feature)