A card security code is a three- or four-digit number on the back of credit and debit cards that ensures the authenticity of transactions when a physical card is not presented at the point of sale.

Today's debit and credit cards include a verification or security code. This is a four-digit code printed on the front of American Express cards and a three-digit version on the back of MasterCard ...

Fraud prevention is a major concern for many people. To prevent fraudulent charges, most merchants require customers to provide their debit or credit card number, its expiration date and a numeric ...