CVV (Card Verification Value) / CSC (Card Security Code):

The Card Verification Value (CVV), also known as the Card Security Code (CSC), is a critical security feature used primarily in card-not-present transactions, such as those made online or over the phone. This code helps verify that the cardholder making a transaction has physical possession of the credit or debit card being used. The CVV is a 3- or 4-digit number that is either printed or embossed on the card.

For Visa and MasterCard, the CVV (referred to as CVV2 for Visa and CVC2 for MasterCard) consists of three digits and is located on the back of the card, typically in the signature panel. American Express refers to this code as the Card Identification Number (CID) and places a four-digit code on the front of the card.

The purpose of the CVV is to enhance the security of the card by adding an extra layer of protection against unauthorized use, particularly in situations where the card is not physically present, such as in online purchases. By requiring the CVV during a transaction, merchants can reduce the risk of fraud by ensuring that the person making the transaction has direct access to the card itself, and not just the card number or other details.

This security feature is pivotal in minimizing the risks associated with online transactions, providing both consumers and merchants with an additional assurance that the transaction is being conducted by the rightful cardholder.