International Journal of Advancements in Research & Technology, Volume 2, Issue4, April‐2013 327 ISSN 2278‐7763 Copyright © 2013 SciResPub. IMPROVING DATA DYNAMICS AND STORAGE SECURITY IN CLOUD COMPUTING Badi Alekhya Department of CSE T.J.S Engineering College Chennai, India E-mail: alekhyareddy1@gmail.com ABSTRACT: Cloud computing is a internet based computing which enable sharing of services. Many users place their data in the cloud, so correctness of data and security is a prime concern. This work studies the problem of ensuring the integrity and security of data storage in Cloud Computing. Security cloud is achieved by signing the data block before sending to the cloud. Signing is performed using BLS algorithm which is more secure compared to other algorithms. To ensure the correctness of data, we consider the task of allowing a third party auditor (TPA), on behalf of the cloud client, to verify the integrity of the data stored in the cloud. By utilizing public key based homomorphic authenticator with random masking privacy preserving public auditing can be achieved. The technique of MD5 (message digest) signature and scheduling policies is used to achieve batch auditing. Batch auditing reduces the computation overhead. As the data in the cloud is used by many industries modification of data cannot be avoided. Unlike most prior work, the new scheme further supports secure and efficient dynamic operations on data blocks, including: data update, delete and append. We explore the efficient technique for error correction called reed Solomon technique which ensures the correctness of data. Keywords: Third Party Auditor, Boneh–Lynn–Shacham, Bilinear aggregate signature, Reed Solomon technique. I. INTRODUCTION Cloud computing is a general term for anything that involves delivering hosted services over the internet. These services are broadly divided into three categories: Infrastructure‐as‐a‐Service (IaaS), Platform‐as‐a‐Service (PaaS) and Software‐as‐a‐Service (SaaS). A cloud service has three distinct characteristics that differentiate it from traditional hosting. It is sold on demand, typically by the minute or the hour; it is elastic ‐ a user can have as much or as little of a service as they want at any given time and the service is fully managed by the cloud service provid‐ er (the consumer needs nothing but a personal computer and Internet access). The advantage of cloud is cost sav‐ ings. The prime disadvantage is security. Cloud compu‐ ting is used by many software industries nowadays. Since the security is not provided in cloud, many com‐ panies adopt their unique security structure. For eg) Amazon has its own security structure. Introducing a new and uniform security structure for all types of cloud is the problem we are going to tackle in this paper. Since the data placed in the cloud is accessible to everyone, security is not guaranteed. To ensure security, crypto‐ graphic techniques cannot be directly adopted. Some‐ times the cloud service provider may hide the data cor‐ ruptions to maintain the reputation. To avoid this prob‐ lem, we introduce an effective third party auditor to au‐ dit the user’s outsourced data when needed. The security is achieved by signing the data blocks. Signing is per‐ formed using BLS algorithm. We utilized public key based homomorphic authenticator with random masking to achieve privacy preserving auditing protocol.TPA performs the auditing task for each user i.e. single audit‐ ing. This increases the auditing time and computation overhead. The technique of Bilinear Aggregate Signature is used to achieve batch auditing i.e.) multiple auditing tasks simultaneously. Earlier works performs auditing only for static data. We enhance the system with dynam‐ ic operations on data blocks i.e.) data update, append and delete. Reed Solomon technique is a best error cor‐ rection technique which ensures the correctness of the data stored in cloud. Our contribution in this paper is summarized as follows: We provide a privacy preserving auditing