The credit card system first appeared in the United States as 1920s, which originated from monthly billing services provided by some businesses, such as gas stations (called credit in China). Later, many merchants joined hands to let customers use one account in different merchants and provide monthly statements together. This way of helping merchants to provide unified credit services has developed to well-known card issuers such as MasterCard, Visa and American Express. At that time, there were no tools for electronic finance, and naturally there was no password. The basis for verifying the customer's identity is the cardholder's account information and signature authentication. The current credit card system, taking MasterCard as an example, is a four-party trading platform (AE is a three-party platform with its own banking function, which is not mentioned here). When you submit consumption information at a consumer terminal (POS machine, website, etc.). ), your credit card information will be transmitted to the merchant's bank first, and then the merchant's bank will transfer this information to MasterCard for identity authentication. After authentication, MasterCard will verify whether there is sufficient credit with the issuing bank (the consumer's own bank). After this authentication procedure is completed, MasterCard will contact the merchant's bank again, and the final feedback will show the success of the transaction on the consumer terminal. After swiping the card, the merchant's bank will formally submit the consumer confidence to MasterCard, and then MasterCard will act as the intermediary of the bank and complete the transfer through its agent bank.

American credit cards have no passwords. If the credit card is stolen, you can call the bank to lock the card immediately. In addition, in order to ensure the safety of customers, unconditional refund is the selling point of many American credit card companies. Moreover, when the single consumption is too high or there is no previous consumption record in different places, the credit card may be automatically frozen and can continue to be used normally after confirmation. If it is found that it is not my consumption after freezing, the card will be frozen and cancelled, and the account holder will get a new credit card with a Qvanxian Zhang number.

According to American law, individuals whose bank cards are stolen are liable for up to $50. Even if $999,999 is stolen, the remaining $999,949 should be borne by banks and businesses. Therefore, American businesses are very concerned about anti-theft brushes. For example, they may need to verify the postal code of the billing address. When they see an overseas card, they also need to see their passport or driver's license to verify the name and photo of the card owner.