HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP, the protocol over which data is sent between a browser and a website. The 'S' at the end of HTTP stands for 'Secure' and it means that all communications between the browser and the website are encrypted using SSL (Secure Sockets Layer). Therefore, SSL encryption is essentially part of the HTTPS protocol, providing a secure connection by encrypting and protecting the data that is being transferred. This method ensures that any sensitive information like login details, payment information, etc, sent over the internet, cannot be stolen or tampered with by malicious parties.