There are 7 digits behind the credit card, the first four digits are the last four digits of your credit card number, and the last three digits are your credit card security code. Whether it belongs to VISA or MASTER credit card, the principle of generating security code is the same. The security code of credit card is mainly used as verification code for online transaction or credit card cancellation.

The three digits on the back of a credit card are as important as the cardholder's signature and belong to the "secret" of the credit card, so the cardholder should keep them properly. It is suggested that credit card holders who frequently conduct online transactions must ensure the safety and legality of the merchants who conduct transactions with them, and prevent the digital information on the card surface from being leaked to irrelevant personnel, otherwise it will bring credit card security risks to themselves.