Http Protocol is a communication protocol consisted on a complete system that includes rules, designs and configuration for the digital messages, which are going to be exchanged between the computing organizations. 
HTTP (hyper text transfer protocol) as a communication protocol was anticipated in the year 1989 by 1.0 specification coauthor, Tim Berners Lee. This set of practicing rules is the key to connect to the web servers either over internet or intranet. Moreover, this protocol operates over another protocol’s top, named as TCP/IP. In OSI (open systems interconnection) Model, HTTP operates while residing at the uppermost’s layer, known as Application layer.
Two main functions of this protocol are including:
- To provide connection with web servers and after connecting to one, requested html pages are sent back to user the web browser (software application for the purpose of retrieving and presenting information).
- Another function of this standard level http protocol is to supply requested file’s downloading from a destination server that can be a browser or http based application.
A web browser as an HTTP client can send request for a file to the web server that is all time ready to handle such situation using http service as a result of demand. As, this protocol is the standard setting of a web browser so you can type either www.hotmail.com or http://www.hotmail.com, both cases will considered as same by browser. WWW is used this underlying protocol in order to make the messages formation and transmission clear over the internet. Anyhow, different responses of web servers and client browsers are performed using a number of commands. Entering URL of a site into the address bar can be meant as sending HTTP command to a specific server for getting the requested pages of that specified site. One more feature of this protocol is its state of independent commands accomplishment for which it is known as a stateless protocol because each command is executed autonomously.
But an additional “s” with HTTP at its end indicates that requested site is a secure and an encrypted site. You can say that https is the grouping of http and SSL/TLS protocol. Purpose of https connection is to provide an authentic network’s web server detection using the encrypted communication way. Reason of https need and regard is due to the attached insecurity with http protocol that is subjected of eavesdropping or third person attacks which are made to deceive others by stealing their website accounts or other sensitive information. That’s why; this protocol is designed to resist such attacks made with malice.
HTTPS is considered a good way to be secure against such attacks. You too can observe that money transaction related sites often used https connections over the internet. But Https should be considered as a separate protocol in the strict sense, because it is just the http exercising over a secure SSL/TLS encrypted connection. In the https message, everything including the headers, request, and response load is encrypted as a result. But https is different from s-http (secure http). Another term “http proxy” is referred to a bridge that can act as http server or http client.