CVV is the abbreviation of "Credit Card Verification Value (Credit Card Verification Value)". Generally speaking, CVV is a three- to four-digit verification code, usually located on the right side of the signature area on the back of the credit card. It usually consists of a number of numbers on the credit card. CVV is usually important information used to verify the identity of the cardholder in non-face-to-face credit card transactions such as online shopping and phone purchases. Therefore, to protect the security of credit cards, the CVV value does not appear on the credit card's issuing bank statement or other documents.

CVV is one of the key factors in credit card transaction security and fraud prevention. It is a way to verify the identity of the credit card holder during the purchase process. Merchants and websites often require customers to enter a CVV code to complete a purchase transaction. Since the CVV code will not appear on any credit card repayment slips or other documents unrelated to the transaction, it is an effective means of preventing fraud for merchants conducting non-face-to-face transactions.

Some merchants enhance the security of transactions by performing further security verification on the CVV code on the credit card. For example, some merchants may ask customers to enter the three digits after the expiry date on their credit card to ensure that the cardholder is the same as the card number and further reduce the risk of fraud. Therefore, CVV is crucial to the security of credit card transactions.