At present, there are two online credit card payment systems: 1. Provide credit card number and expiration date for mail order payment; 2. Apply two encryption services: Visa verification and MasterCard security code provided by Visa International and MasterCard respectively.

The first is the traditional payment method, which is slow in transaction speed and low in security, and is easy to cause economic losses to cardholders (such as fraud and overpayment).

The second is the emerging transaction payment system, and many online businesses have registered for this service. You can understand that Visa and MasterCard are middlemen, and merchants and cardholders only deal with middlemen, so cardholders don't need to worry about data being stolen by merchants, which is safe and reliable. Its limitation is that if the cardholder is registered and the merchant is not registered for this service or vice versa, it cannot be used.