Present days many users store their significant data in cloud. To ensure that the security of the cloud stored data users need to encrypt the important data. The point of data security which has always been noteworthy aspect of quality, cloud computing cause a new security threats. In cloud storage systems, the server that stores the client’s data is not necessarily trusted. The existing system does not provide security mechanisms for storing data in clouds, but the propose system can provide security against for Collusion attack, DDOS attack. Existing data auditing schemes have security risks in processing of data. For achieving the efficiency of cloud storage, the proposed system provides flexible data segmentation with additional authorization process among the three participating parties of client, server and a third-party auditor (TPA). We propose an identity based data storage scheme, it will resist the collusion attacks.