Hypertext Transfer Protocol Secure (HTTPS) is a widely used communications protocol for secure communication over a computer network, with especially wide deployment on the Internet. Technically, it is not a protocol in itself; rather, it is the result of simply layering the Hypertext Transfer Protocol (HTTP) on top of the SSL/TLS protocol, thus adding the security capabilities of SSL/TLS to standard HTTP communications. HTTPS provides authentication of the web site and associated web server that one is communicating with, which protects against Man-in-the-middle attacks. Additionally, it provides bidirectional encryption of communications between a client and server, which protects against eavesdropping and tampering with and/or forging the contents of the communication
There are some primary differences between http and https, however, beginning with the default port, which is 80 for http and 443 for https. Https works by transmitting normal http interactions through an encrypted system, so that in theory, the information cannot be accessed by any party other than the client and end server. There are two common types of encryption layers: Transport Layer Security (TLS) and Secure Sockets Layer (SSL), both of which encode the data records being exchanged.
When using an https connection, the server responds to the initial connection by offering a list of encryption methods it supports. In response, the client selects a connection method, and the client and server exchange certificates to authenticate their identities. After this is done, both parties exchange the encrypted information after ensuring that both are using the same key, and the connection is closed. In order to host https connections, a server must have a public key certificate, which embeds key information with a verification of the key owner’s identity. Most certificates are verified by a third party so that clients are assured that the key is secure.