Question : CVV2 checker for C# code

Is there a formula for checking the CVV2 code to see if it is valid? I have the MOD10 formula for the credit cards, but do not know if there is a similar formula for CVV2, so I can check it before passing it to the payment gateway.

I would appreciate it if you could post the code as a c# function, either returning boolean (valid or not) or int (as what the code should be : 123, for example).

Answer : CVV2 checker for C# code

As far as I know there is no algorithm that you can use. There is an algorithm which I list below, however, the DES keys are only known by the bank so you would not be able to generate it. I tried a couple of those CVV2 generators you can find online and they either calculated the wrong CVV2 code or were malware.

Primary Account Number (PAN), a 4-digit Expiration Date, a 3-digit Service Code, and a pair of DES keys (CVKs).