Cloud computing has become popular and adopted by large number of industries (or) enterprises who outsource their IT services to cloud service provider (CSP). The maintenance and operations of their services have become easier and cost effective. Data processing services are one among the major and important component in IT services, since IT functions progress around data processing. In particular privacy and security of user's data brings many challenges that have not been effectively addressed. A specific problem occurs when clients outsource their files (contains data) to the cloud storage server and the services are offered by cloud service provider (CSP), which is an untrusted entity. In this paper we introduce an Index Table Structure (ITS) based public auditing scheme to verify the integrity of the data stored in a cloud. Previous work requires CSP to store and maintain the data property information needed for auditing. In our approach we keep the data auditing information in trusted third party auditor (TTPA), results in reducing communication overhead and computational cost. Our method is a public auditing scheme based on ITS with TTPA, who performs auditing on behalf of the user. We extend our work to support privacy preserving property by signing the proof generated by cloud server during verification process. Thus, the result shows our proposed scheme is secure and provide with better efficiency.