The display position is on the back of the credit card, and the top of the signature is displayed in italics. The first four digits are the card number and the last three digits are the verification code, that is, the last three digits. Note that this verification code does not refer to the password of the credit card, just enter the bank card number and its last three digits, and the validity period of the credit card, and there is no password at all.
The last three digits are the last three digits on the back of a series of cards, which are generated by the coding rules and encryption algorithm of the issuing bank. In the payment process, if the merchant provides the last three codes to the bank, the bank will obtain the authorization of the cardholder to the merchant by default, thus allowing the transaction.
Extended data
CVV password verification means that commercial banks add verification code (CVN) of self-defined encryption algorithm to the bank card number coding rules and magnetic stripe data format they use, and related bank cards are also called CVN bank cards.
CVV information is stored in the track of magnetic stripe bank card. According to the information such as card number, track main account number and logo code of issuing bank, it is encrypted by special encryption algorithm defined by each bank, and every step is encrypted by CVKA technology to get verification code. Because the encryption algorithms of different banks are different, some fake cards illegally made by using the obtained bank card information can be identified and cannot be used when the issuing bank decrypts them.
Baidu Encyclopedia-Last Three Codes
Baidu Encyclopedia -CVV Code