Seven digits behind the credit card, the first four digits are the last four digits of the credit card number, and the last three digits are the security code of the credit card.

As shown in the figure below:

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

The security code of credit card is mainly the verification code for online transaction or credit card cancellation.

The three digits on the back are as confidential as the cardholder's signature, so keep them properly.

It is suggested that cardholders who are keen on online transactions must ensure the authenticity and legitimacy of the businesses that conduct transactions, and do not disclose card information to others casually, otherwise it will leave themselves with security risks.