Cloud computing is the newest term for the ongoing-dreamed vision of computing as a utility. The cloud provides convenient, on-demand network access to a centralized pool of configurable computing resources that can be rapidly deployed with great efficiency and minimal management overhead. The industry leaders and customers have wide-ranging expectations for cloud computing in which security concerns remain a major aspect Dealing with “Single cloud” providers is becoming less popular with customers due to potential problems such as service availability failure and the possibility that there are malicious insiders in the single cloud.