Essential characteristics of Cloud Computing: The National Institute of Standards and Technology (NIST) defines cloud computing through five particular characteristics. (i) On-demand self-service : Self-service means that the consumer performs all the actions needed to acquire the services such as Email, Network Storage, or Server time . Such services can be availed without interaction with service providers like Amazon Web Services (AWS), Google and Salesforce.com. (ii) Broad network access: Cloud services are available over the network and accessed through several thin or thick client platforms such as mobile phones, laptops and PDAs. (iii) Location independent resource pooling : Cloud computing resources are designed to support a multi-tenant model. Multi-tenancy allows multiple customers to share the same applications or the same physical infrastructure while maintaining privacy and security over their i...