Explanation/Reference:
* Secure Sockets Layer (SSL) is a cryptographic protocol designed to provide communications security over a computer network, such as secure connections to websites.
* SSL is used for encryption but not for authentication.
* There is SSL for the web server, but the client does not have a SSL certificate.
SSL Certificates are small data files that digitally bind a cryptographic key to an organization's details.
When installed on a web server, it activates the padlock and the https protocol (over port 443) and allows secure connections from a web server to a browser.
Reference: https://www.globalsign.com/en/ssl-information-center/what-is-an-ssl-certificate/