the p>CVV code is on the signature column on the back of the credit card. CVV code is used to confirm that the payer really owns the credit card at the time of transaction, and it is the only character owned by the cardholder that the bank staff can't get from the industry system. CVV code can be used to verify the authenticity of credit cards and effectively prevent fraud or credit theft.

CVV is a 3-digit or 4-digit number generated by card number, expiration date and service constraint code, which is generally written in the 2-track user-defined data area of card magnetic stripe. CVV is a number printed in the signature area of Visa/Master Card card, which is a 3-digit number after the credit card number. CVV code is actually a non-magnetic and non-secret payment channel. You don't need to swipe your card or check your password. You only need to provide the card number and the three-digit verification code on the back of the credit card to complete the payment. This kind of transaction without physical card and password is called "no card payment" and "no card and no secret payment". It is mainly used for telephone payment and belongs to offline transactions of credit cards.

Although this payment method is simple and fast without a physical card or password, it also brings huge security risks. It can be consumed by providing the card number and the three digits behind it and checking personal information. Then, even if the card is not stolen, once it is accidentally revealed or personal information such as birthday and mobile phone number is set by criminals, it is easy for individuals to suffer huge economic losses. In addition, for more and more popular online shopping, the website only needs to enter the ID number, cardholder's name, credit card number and three CVV security codes on the back of the credit card to declare the transaction successful, and there is no need to enter the credit card password at all. It can be seen that the contracted merchants with this kind of "non-magnetic and non-secret" channel have the technical advantage of freezing or deducting money without confirming whether the cardholder is the consumer himself. Although for those businesses with "credit", it will not pose a threat to the cardholder's card safety, but for those unscrupulous businesses or lawless elements, it is tantamount to opening the door to illegal profit. Therefore, the protection of CVV code is very important, and cardholders should take precautions in daily life to prevent their credit cards from being stolen.