HTTPS carries web pages over an encrypted connection.
HTTPS means Hypertext Transfer Protocol Secure. It uses HTTP together with a cryptographic security layer, traditionally SSL and now usually Transport Layer Security. The browser and server negotiate security parameters, authenticate the server with a certificate, and encrypt application data sent during the session.
Encryption helps prevent people on the network from reading or changing traffic in transit. A certificate also helps the browser verify that it is communicating with the intended domain, although HTTPS does not guarantee that a website’s content is truthful or harmless.
HTTPS commonly uses TCP port 443, while unencrypted HTTP traditionally uses port 80. Modern HTTP versions can run over other transport technologies, but the defining feature of HTTPS is protected HTTP communication rather than a particular page design or browser brand.