The first four digits on the back of a credit card are the last four digits of the credit card number, and the last three digits are the credit card's security code.

As shown below:

Whether it is a credit card organized by VISA or MASTER, the principle of generating the security code is the same.

The security code of a credit card is mainly a verification code for online transactions or credit card account cancellation.

The three-digit number behind it is as "confidential" as the cardholder's signature and should be kept properly.

It is recommended that cardholders who are keen on online transactions must ensure the authenticity and legality of the merchants conducting transactions, and do not leak card information to others casually, otherwise they will leave themselves with security risks.