The security model adopted for credit card online payment is as follows:

1. Payment through a third-party broker: Payment is completed through a third party trusted by both parties. Credit card information is not transmitted multiple times over an open network, and the buyer may open an account with a third party offline, so the buyer does not have the risk of credit card information being stolen. The seller trusts the third party, so there is no risk to the seller either. The buyer and seller obtain some kind of agreement from a third party in advance, that is, the buyer opens an account with the third party and the seller becomes the third party's special merchant.

2. Simple credit card encrypted payment: When paying using the simple encrypted credit card mode, when the credit card information is entered by the buyer into a browser window or other e-commerce device, the credit card information is simply encrypted and securely used as encrypted information. Passed from buyer to seller over the network.

3. SET credit card payment: SET is the abbreviation of Secure Electronic Transaction. It is an open electronic payment protocol standard based on electronic money established for online transactions on the INTERNET. SET's security measures mainly include: symmetric key system, public key system, message digest, digital signature, digital envelope, double signature, authentication and other technologies.