Cloud computing comes into focus only when the people think about what IT always needs: a way to increase capacity or add capabilities on the fly without investing in new infrastructure, licensing new software. Besides of this advantage there is one major problem the user have to face while keeping their private data in cloud, assurance of their data will remain unaffected by external as well as internal threat and security are major concerns as there are chances for CSP to behave unfaithfully with users regarding the status of their outsourced data.