The last three digits on the back of the credit card play the role of security protection. The credit card security code is a set of 3 or 4 digits on the credit card. The generation method is that the bank extracts the account number, validity period and service code of the card, and then calculates it through a series of complicated algorithms. After generating this set of numbers, only the card issuer and the cardholder know what the numbers are. Credit card security code is a security code used by credit cards for online or telephone transactions. It is usually used to verify whether the payer has a credit card at the time of transaction, thus preventing credit card fraud. Don't let anyone know! If the information is leaked, you can call customer service to hang up and change the card. After changing the card, the security code should also be changed.
I. Identification
The "last three digits code" is the last three digits located at the signature on the back of the credit card, also known as CVV or CVC code, which is generated by the coding rules and encryption algorithm of the issuing bank. Generally speaking, these three numbers are unique and are used to identify individuals. Generally, it is impossible to pay for an input error.
Second, there is a certain authorization
In the process of use and payment, 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.
Third, prevent brush theft.
Banks have strict supervision over credit cards. For example, a credit card with an overdraft limit of 50,000 yuan will be overdrawn once in a short time. If the issuing bank suspects that the card has a tendency to cash out, it will remind the cardholder. If the reminder is invalid, the right to use the credit card will be suspended.