Card Identification Number (American Express)

The Card Identification Number for American Express cards, commonly referred to as CID, is an additional security feature similar to the Card Verification Value (CVV) used by Visa and MasterCard. The CID is a four-digit number located on the front of American Express cards, typically printed above the embossed (raised) account number.

This number is used as a security measure in card-not-present transactions, such as those conducted online or over the phone. The purpose of the CID is to verify that the person making the transaction physically has the card in their possession and that the card account is legitimate. This helps to prevent unauthorized use and reduce the risk of fraud in transactions where the card is not physically swiped or inserted into a payment terminal.

The inclusion of a CID is part of American Express's comprehensive approach to security and fraud prevention, ensuring that transactions are safe and that the cardholder's data is protected. Merchants are required to ask for the CID as part of their transaction authorization processes but are prohibited from storing this sensitive information to comply with PCI DSS standards. This ensures that even if transaction data is compromised, the security code cannot be used to perpetrate further fraudulent activities.