A self-generated SSL certificate, also known as a self-signed certificate, is a certificate signed by the creator, not a certificate issued by a trusted certificate authority.

The difference between self-signed certificates and trusted SSL certificates is that self-signed certificates generally have serious security vulnerabilities, are vulnerable to attacks, and are usually not trusted by browsers. Therefore, it is not recommended to use self-signed certificates to avoid huge security risks and hidden dangers, especially important online banking systems, online securities systems and e-commerce systems. This is not the case for trusted SSL certificates.

Using self-signed certificates has two main disadvantages:

1) The visitor's connection may be hijacked, so that the attacker can view all the sent data (thus defeating the purpose of encrypting the connection).

2) Certificates cannot be revoked like trusted certificates.