Turn over the credit card. There are several numbers on the cardholder's signature, and the last three digits are the credit card security code. As shown below:

Expand knowledge:

1. Credit card security code is a security code for credit cards when conducting online or telephone transactions. It is usually a 3 or 4-digit number printed on the credit card, and the location of the printing will vary on different types of cards. It is often used to prevent credit card fraud by verifying that the payer owned the credit card at the time of the transaction.

2. The method for generating credit card security codes is that the bank extracts the card account number, validity period, and service code, arranges them, and then calculates them through a series of complex algorithms. After this set of numbers is generated, only the issuing bank and the bank card holder know what the number is.

3. The security codes of different credit cards have different locations.

(1). The VISA card has a 3-digit number, which is printed flat on the signature line on the back of the credit card at the last 4 digits of the card number.

(2). MasterCard has a 3-digit number, which is printed flat on the signature line on the back of the credit card at the last 4 digits of the card number.

(3). The discovery card has a 3-digit number printed flat on the signature line on the back of the credit card.

(4). American Express cards have a 4-digit number printed flat above the credit card number on the front of the credit card.

(5) UnionPay cards have a 3-digit number, which is printed flat on the signature line on the back of the credit card after the last 4 digits of the card number.

(6). The JCB card has a 3-digit number, which is printed flat on the signature column on the back of the credit card at the last 4 digits of the card number.

Reference material: Credit card security code