CVV code, but this step is not necessary.

There is a 7-digit number at the top of the cardholder's signature on the back of the credit card, shown in italics. Among them, the first 4 digits are the last four digits of the card number, and the last 3 digits are the credit card verification code, which is called the CVC code or CVV code.

CVV password verification means that commercial banks add a custom encryption algorithm verification code (CVN) to the bank card number coding rules and magnetic stripe data format they use. Related The bank card is also called a CVN bank card.

The CVV information is stored in the magnetic track of the magnetic stripe bank card. Based on the card number, track master account number, card-issuing bank logo code and other information, it is encrypted through a special encryption algorithm customized by each bank. Each step uses CVKA technology encrypts and gets the verification code. Since the encryption algorithms of different banks are different, some counterfeit cards illegally produced using the obtained bank card information can be identified and cannot be used when the card issuer decrypts them.

Security level

The process for the website to accept credit cards is basically one of the following three situations:

Card number + validity period

This Most of them are airline, hotel booking or car rental booking types.

Card number + validity period + CVV2 code

The reason why a CVV code on the back of the card is added is to confirm that the card is indeed in the hands of the cardholder. So when you usually swipe your card outside, be careful not to let others see it easily, especially record the three-digit number to prevent others from stealing the card number and the expiration date and then using it online

Card number + expiration date + CVV2 code + "Visa verification" code

　(Verified by Visa).

This last code is a password agreed in advance between the card-issuing bank and the cardholder and specifically used for online card verification. When paying at a merchant that supports the "Visa Verification" code, after filling in the information in B, the website will pop up a page (this page is actually for the card-issuing bank. If you look carefully, you can find that the blue address bar at the top of the window shows the card-issuing bank. URL, and the pop-up page has the card-issuing bank's LOGO), requiring you to fill in the "Visa Verification" code. This web page is actually separate from the merchant, and the identity verification is completed directly between the cardholder and the bank, which also ensures that the "Visa Verification" code will not be intercepted by the merchant. Better protection of cardholder security.