HTTPS is a variant of http for handling secure transactions. A secure http request is made using an URL of the type “https://…” instead of the “http://…” request used for ordinary http. The default “https” port number is 443, as assigned by the Internet Assigned Numbers Authority.

In a secure http transaction, data sent to and received from an https server are protected usingSecure Socket Layer (SSL) orTransaction LayerSecurity (TLS). Thus https is a two-step process in which security mechanisms and the necessary session keys are agreed initially. These session keys establish a secure tunnel during which the actual messages can be subsequently transmitted. The secure http server must have a certified public key (seecertificate andpublic key cryptography), which is used when exchanging the session keys (e.g., the client generates and encrypts a common secret under the public key of the server). Only a server having the private key corresponding to the public key in the certificate...