To prevent fraudulent charges, most merchants require customers to provide their debit or credit card number, its expiration date and a numeric code — known as a card security code — located ...

Most debit cards have a three-digit CVV ... card validation code, or card security code. Does a CVV have 3 or 4 digits? Cards issued by Visa and Mastercard usually have three-digit CVVs.

The debit card contract with Money Network called for putting security chips on those cards ... Mastercard and Visa;" the chips create codes to identify individual transitions.) ...