Cloud computing has become a buzzword that nearly everyone has heard but only few can truly understand its correct meaning. Today, cloud has taken over the IT landscape. Cloud computing refers to menu of hosting services usually provided over the internet on a usage or metered basis, while at the same time leveraging infrastructure shared by multiple users. Cloud itself is maintained by cloud service providers through networked "Server farms". They offer their subscribers unlimited availability and data storage, along with the seamless access to software, application provisioning and automatic upgrades. Security is one of the most concerning downsides while using cloud services.