Cloud computing is a recently developed information technology (IT) that utilizes resources virtualization approach to deliver IT services through Internet technology and on-demand mode. National Institute of Standards and Technology (NIST) defined cloud computing, on its web page, as “a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction” [18]. NIST classified the cloud deployment into the following four categories: private cloud, community cloud, public cloud, and hybrid cloud [18].