Similar points:

All three are network security protocols. All can ensure the security, confidentiality and integrity of transaction data.

Difference:

SSL is called the Secure Socket Layer protocol. It is the earliest used in the world and has become an industrial standard. If the SSL Secure Socket Layer protocol is used on the Web server, it will Convert the original http (Hypertext Transfer Protocol) to "https" (which can be called "Hypertext Transfer Protocol Secure"). SSL encrypts network connections at the transport layer. In addition to https applications, it can also be applied to B/S architecture applications. Its basis is the measures taken by merchants to keep customer information confidential. It only achieves security, confidentiality and integrity for merchants and users, but cannot prevent transaction denial. The merchant is authenticated before use. After the merchant actually uses it, only the user is authenticated, which is single authentication.

SET, called Secure Electronic Transaction Protocol, is an open specification established to ensure the security of credit card payments during online transactions on the Internet. Because its objects include consumers, merchants, card-issuing banks, acquiring banks, payment gateways, and authentication centers, it is equally beneficial to consumers and merchants. In order to achieve the goal of merchants legally verifying the cardholder's payment instructions and banks legally verifying the cardholder's ordering information without infringing on the customer's privacy, the SET protocol uses double signature technology to ensure that the customer's privacy is not violated. Usually two-way authentication is required.

S-HTTP stands for Secure Hypertext Transfer Protocol, which is the Secure Hypertext Transfer Protocol. It is a protocol that works at the application layer, so it can provide message-based non-repudiation. However, the current maturity level is not high.