Cloud computing is a significant shift of computational paradigm where computing as a utility and storing data remotely have a great potential. Cloud server provides a low cost, flexible, location independent platform for storing client's data. It can provide user along with varieties of service, framework, applications and storage of a huge amount of data; it includes information which is important. Along with the capabilities of the cloud computing, its security is the biggest question mark. It needs associate an independent third party auditing service to see the data integrity within the cloud server. Already past integrity checking methods will solely serve for static archive data and so cannot be applied to the auditing service since the data within the cloud may be dynamically updated.