SSL (Secure Sockets Layer) is a security protocol that establishes an encrypted link between a web server and a browser. This link ensures that all data transmitted between the web server and browsers remains private and secure. The SSL protocol uses encryption to prevent hackers from intercepting and reading transmitted data, which is crucial for protecting sensitive information such as credit card details, usernames, passwords and other personal data.
When a website uses SSL, the site's URL begins with "https://" instead of "http://" and a padlock is usually shown in the browser's address bar, indicating that the connection is secure. Companies obtain SSL certificates through Certificate Authorities (CA) that validate the website owner's identity before issuing the certificate.
Over time, SSL has evolved and is now considered part of Transport Layer Security (TLS), SSL's successor, although the term SSL is still commonly used to refer to this type of connection security.