The credit card security code is equivalent to the identity document of the credit card, and people can use this code to buy and sell.

You don't need a login password to buy things on overseas websites. If the buyer shows his account and password, he can buy and sell things. In China, stores also sign contracts with banks, but they don't need a credit card login password, only need a PIN code to remit money. Therefore, everyone must take good care of their credit cards, and don't let them leave their sight when canceling, so as to avoid others remembering your credit card account number and PIN code.