2076 Copyright © 2016, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 91 DOI: 10.4018/978-1-4666-9466-8.ch091 Data Security Issues and Solutions in Cloud Computing ABSTRACT Cloud is considered as future of Information Technology. User can utilized the cloud on pay-as-you use basis. But many organizations are stringent about the adoption of cloud computing due to their con- cern regarding the security of the stored data. Therefore, issues related to security of data in the cloud have become very vital. Data security involves encrypting the data and ensuring that suitable policies are imposed for sharing those data. There are several data security issues which need to be addressed. These issues are: data integrity, data intrusion, service availability, confdentiality and non-repudiation. Many schemes have been proposed for ensuring data security in cloud environment. But the existing schemes lag in fulflling all these data security issues. In this chapter, a new Third Party Auditor based scheme has been proposed for secured storage and retrieval of client’s data to and from the cloud service provider. The scheme has been analysed and compared with some of the existing schemes with respect to the security issues. From the analysis and comparison it can be observed that the proposed scheme performs better than the existing schemes. INTRODUCTION Cloud Computing is a new computing model that distributes the computation on a resource pool. The resource pool which contains a large amount of computing resources offers services to the clients. These services are provided to the cloud users as utility services. The utility services are generally described as XaaS (X as a Service) where X can be software, platform or infrastructure. Many organizations deal with the storage, retrieval and maintenance of huge amount of Abhishek Majumder Tripura University, India Sudipta Roy Assam University, India Satarupa Biswas Tripura University, India