Cloud computing is new model that helps cloud user to access resources in pay-as-you-go fashion. This helped the firm to reduce high capital investments in their own IT organization. Data security is one of the major issues in cloud computing environment. The cloud user stores their data on cloud storage will have no longer direct control over their data. The existing systems already supported the data integrity check without possessions of actual data file. The Data Auditing is the method of verification of the user data which is stored on cloud and is done by the TTP called as TPA. There are many drawbacks of existing techniques. First, in spite some of the recent works which supports updates on fixed-sized data blocks which are called coarse-grained updates, do not support for variable-sized block operations. Second, an essential authorization is missing between CSP, the cloud user and the TPA. The newly proposed scheme will support for Fine-grained data updates on dynamic data using RMHT algorithm and also supports for authorization of TPA.