Self signed Certificates - JohnHau/mis GitHub Wiki

Other than TLS/SSL certificates signed by a CA, there’s also something called self-signed certificates. These certificates are signed by the owner of the server themselves. Though they offer the same level of encryption as a CA-issued certificate, they are usually not trusted by clients which are configured to recognize only certificates issued by a known CA. In case a connection does get established between a self-signed certificate server and the browser, the owner of the server remains anonymous. Self-signed certificates can be created by hijackers as well.

Because of the security threats that they pose, these certificates are to be deployed only in the local environment for testing or troubleshooting purposes and not for public use.