The three digits on the back of ICBC's credit card are in the signature column. The total number is seven, and the first four digits are the four-digit tail number of the card number. The last three digits are the card-free transaction verification code of the credit card, as shown below:

According to the staff of the bank, the last three digits of the signature column on the back of the credit card are the password verification code for card-free transactions, which is used by cardholders to verify their identity when making card-free consumption. Need to be reminded that once the cardholder reveals these three figures, it is easy to cause the amount in the card to be stolen!