SSL (Secure Sockets Layer) is a standard security technology for establishing an encrypted link between a server and a client—typically a web server (website) and a browser, or a mail server and a mail client (e.g., Outlook).
SSL allows sensitive information such as credit card numbers, social security numbers, and login credentials to be transmitted securely. Normally, data sent between browsers and web servers is sent in plain text—leaving you vulnerable to eavesdropping. If an attacker is able to intercept all data being sent between a browser and a web server, they can see and use that information.
More specifically, SSL is a security protocol. Protocols describe how algorithms should be used. In this case, the SSL protocol determines variables of the encryption for both the link and the data being transmitted.
Why Do I Need SSL?
One of the most important components of online business is creating a trusted environment where potential customers feel confident in making purchases. Browsers give visual cues, such as a lock icon or a green bar, to help visitors know when their connection is secured.
In the below image, you can see the green address bar that comes with extended validation (EV) SSL Certificates.