In order to realize more perfect instant electronic payment, SET protocol came into being. Set (full name of Secure Electronic Transaction Protocol) is a new electronic payment mode launched by Master Card and Visa in June 1997 in cooperation with Netscape, Microsoft and other companies.

SET protocol is designed based on B2C credit card payment mode, which ensures the security of online shopping with credit cards on the open network. SET is mainly used to solve the transactions between users, merchants and banks through credit cards. It has many advantages such as ensuring the integrity of transaction data and non-repudiation of transactions, so it has become an internationally recognized online transaction standard for credit cards.

Main objectives:

1. Prevent data from being stolen by illegal users and ensure the safe transmission of information on the Internet.

2.SET uses double signature technology to ensure that the information of e-commerce participants is isolated from each other. The customer's data is encrypted and reaches the bank through the merchant, but the merchant cannot see the customer's account and password information.

3. Solve the multi-party authentication problem. Not only the credit card authentication of customers, but also the authentication of online merchants, so as to realize mutual authentication among customers, merchants and banks.

4. Ensure real-time online transactions and make all payment processes online.

5. Provide an open standard, standardize protocols and message formats, and make the software developed by different vendors have the functions of compatibility and interoperability. It can be executed on different software and hardware platforms, and is widely accepted in the world.