Frequency checks used to manage risks.
What is a card verification number?
Different acronyms are used for credit card verification numbers. In the case of Mastercard, for example, it is CVC (Card Validation Code), while Visa calls it the CVV (Card Verification Value). There are several types. The first, called CVC1 or CVV1, is encoded in the magnetic stripe and read to check a physical card when it is used for purchases.
The second code, which is used for online shopping, is CVC2 or CVV2. It consists of three or four numbers that are typically printed on the signature field on the back of a credit card. Merchants can request this code to verify it when the cardholder is not personally present.