The security code of the bank card is the seven digits on the back of the bank card and in front of the cardholder's signature. In fact, the security code and the mobile phone verification code are the same. If it is a credit card, the last three digits of the security code are required to activate the credit card, and this security code is sometimes used when the bank card pays online.

1. If it is a credit card, fill in the last three digits of the signature column on the back of the credit card, namely the credit card security code CVC2 and CVC2. Among them, the security code of Visa is called CVV 2 (card verification value 2); The security code of MasterCard is called CVC2 (Card Verification Code 2).

2. The credit card security code is equivalent to the credit card ID card, and we can use this code for consumer transactions. You don't need a password to shop on overseas websites. As long as the buyer provides the account number and security code, the transaction can be completed. In China, there are also merchants signing contracts with banks, but you don't need a credit card password, you only need a security code to complete the telephone transfer. Therefore, everyone must take good care of their credit cards, and don't let them leave their sight when spending, so as to avoid others remembering your credit card account number and security code.

3. The security code is extracted by the bank from the account number, validity period and service code of the card, and then calculated by a series of complicated algorithms. After this set of numbers is generated, only the issuing bank and the holder of the bank card know what this number is. So this number is very important for credit card holders.

Extended data:

CVV password verification means that commercial banks add the verification code of self-defined algorithm to the bank card number coding rules and magnetic stripe data format they use, and the 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.

References:

Credit card security code Baidu Encyclopedia