Luhn Check Test for CVV Verification

Answer:

A Luhn check test, also known as a mod 10 check, is a simple mathematical method used to validate credit card numbers, CVVs included. By following this test, you can determine if a CVV is valid and has been entered correctly.

How to Perform a Luhn Check Test

• Start by adding the digits of the card number in groups of two, from the rightmost digit (which is the check digit) towards the left.
• Double the value of each digit that falls in an even-numbered position.
• If the doubled value is greater than 9, subtract 9 from it.
• Sum up all the digits of the card number.
• Check if the sum is divisible by 10. If it is, the CVV is valid; if not, it's invalid.