On the back of each credit card, two sets of numbers are usually displayed in italics at the top of the signature. The first four digits are the last four digits of the card number. The last three digits are commonly known as "the last three digits". It is a verification code set by commercial banks to ensure the security of credit card passwords, and it is used for indirect credit card consumption transactions for bank cards. For example, online payment and other transactions, so the "last three yards" of the credit card cannot be leaked.

In addition to the password, credit card number, credit card expiration date, credit card use verification code CVN2 (last three codes) and ID number are also extremely important personal information, which can be used for remote non-face-to-face transactions such as air tickets, business trips, hotel reservations, etc. Don't disclose them easily.