The first four digits are the last four digits of the bank card number. The last three digits are the security code.
The security code of China UnionPay is called CVN2 (Card Validation Number 2). It has 3 digits and is printed flat on the signature line on the back of the credit card after the last 4 digits of the card number.
China UnionPay special reminder: the cardholder’s ID number, bank card number, password, SMS verification code, as well as the credit card’s validity period and verification code (CVN2, the last three digits on the signature strip on the back), This is important information related to the security of account funds, so please keep it properly.
Special reminder that any online shopping refund does not require providing bank card password and CVN2. Any request for an SMS verification code is a scam.
Extended information
The security code of the VISA card is called CVV2 (Card Verification Value 2). It has a 3-digit number and is printed flat on the signature line on the back of the credit card at the last 4 digits of the card number.
MasterCard's security code is called CVC2 (Card Validation Code 2), which has 3 digits and is printed flat on the signature line on the back of the credit card after the 4 digits of the card number.
I found that the security code of the card is called Cardmember ID, which is a 3-digit number and is printed flat on the signature line on the back of the credit card.
The security code of the American Express card is called CID (Card Identification Number), which is a 4-digit number and is printed flat above the credit card number on the front of the credit card.
The security code of the JCB card is called CAV2 (Card Authentication Value 2). It has 3 digits and is printed flat on the signature line on the back of the credit card after the 4 digits of the card number.
People's Daily Online - China UnionPay issued tips for using cards at home and abroad during the Spring Festival: Use bank cards wisely to save money and convenience
Baidu Encyclopedia - Credit Card Security Code