CVV2 is a number printed in the signature area of Visa/Master Card card. It is located in the 3 digits after the credit card number. The last three digits we usually see on the back of a credit card are actually CVV2, not CVV code.

Credit card security code is the security code of credit card for online or telephone transactions. Generally, it is a 3-digit or 4-digit number printed on a credit card, and the printing position of different types of cards will be different. It is usually used to prove that the payer has a credit card at the time of transaction, thus preventing credit card fraud.

Generation algorithm:

1.CVV password verification means that a commercial bank adds a verification code of a self-defined algorithm to the bank card number coding rules and magnetic stripe data format it uses, and the related bank card is also called CVN bank card.

2.CVV information is stored in the track of the magnetic stripe bank card. According to the information such as card number, track main account number, issuer logo code, etc., it is encrypted by special encryption algorithm defined by each bank, and every step is encrypted by CVKA technology to get the 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.