A Certificate Authority (CA) is an organization that issues digital certificates, which are used to establish a secure connection between two parties. The certificate verifies the identity of the server or website, and allows the client to trust the server. The CA is responsible for verifying the identity of the server or website and issuing the certificate.
SSL (Secure Sockets Layer) is a protocol used to secure communication between two computers. SSL relies on the CA to issue certificates that verify the identity of the server or website. Without this verification, the client would not be able to trust the server or website, and the connection would be vulnerable to attack.
For example, when a user visits a website, the web server sends its SSL certificate to the user’s browser. The browser verifies the certificate against the CA’s database to make sure that the certificate is valid and the website is trusted. If the certificate is valid, the browser will establish a secure connection with the web server.