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 and allows secure connections from a web server to a browser
Any computer in between you and the server can see your credit card numbers, usernames and passwords, and other sensitive information if it is not encrypted with an SSL certificate. When an SSL certificate is used, the information becomes unreadable to everyone except for the server you are sending the information to.
For most e-commerce sites, you absolutely need an SSL certificate! As an online merchant, it is your responsibility to make sure the information you collect from your customers is protected. This will shield you and your customers by making sure that no one can intercept and misuse their credit card information.
You have to have a certificate, but it can be one you make yourself. SSL (which is what HTTPS provides) requires a certificate for secure communication because that is the foundation of the encryption and what is used to authenticate that the server is who they claim to be.
SSL means “Secure Sockets Layer”. Many protocols — like HTTP, SMTP, FTP, and SSH '“ were adjusted to include the support of SSL. The port that it typically uses to make a connection to a secure server is 443. Basically, it works as a tier in a certain protocol to provide cryptographic and security functions.