  Cloud computing is one of the innovative computing, which deals with storing
and accessing data and programs over the Internet [1]. It is the delivery of
computing resources and services, such as storing of data on servers and
databases, providing networking facilities and software development platforms
over the Internet. It provides the flexibility of resources for everyone. These
services are provided via data centers, which are located in various parts of
the world [2, 3]. Cloud computing makes access to these resources to everyone
on a global scale at a very minimal cost and significantly higher speed. These
servers provide services to the users, which would have cost a lot of
computational power to them if they had to buy them. The first mention of cloud
computing was referenced in a Compaq internal document released in 1996 [4].
Cloud computing was then commercialized in 2006 when Amazon released elastic
compute cloud (EC2). Furthermore, Google released Google app engine in 2008 and
Microsoft Azure services were launched in October 2008, which increased the
competition in the area of cloud computing. Since then these companies have
done a lot of development in cloud computing.
