APPROACH TO SECURE STORED DATA IN CLOUD COMPUTING

Abstract

In recent years Cloud Computing has gained ample popularity amongst most of the research oriented institutions and organizations. Cloud computing promises scalability of resources and has on-demand availability of resources. However use of Cloud Computing has posed many challenges regarding the security concerns of the user data. In contrast to the traditional solutions where IT services are under proper physical, logical and personnel controls, Cloud Computing moves the application software and databases to the large data centers, where the management of the data and services may not be fully trustworthy. Cloud computing provides its users a combination of economic and performance benefits, but the security issues that are associated with it can’t be neglected. The data stored in the cloud may be frequently updated by the users, using insertion, deletion, modification, appending, reordering, etc. This thesis is focused on cloud data storage security, which has always been an important aspect of quality of service. To ensure correctness and integrity of users’ data on the distributed servers present on cloud, an effective and flexible distributed scheme has been proposed in this dissertation. The proposed scheme makes use of HMAC (Hashed message authentication code) in the form of a homomorphic token and drastically improves data storage correctness and integrity. Further, the implementation of erasure coded techniques, an efficient methodology to recover single or multiple distributed server failure has also been proposed. An analytical comparison has been made between some of the most prominent erasure coding schemes known for accomplishing the above task. On basis of these comparative analyses, Fountain codes are found to give the best results, which justify their use. This thesis basically aims to provide a standard approach for the storage of data in distributed Approach to secure stored data in Cloud Computing Page 5

architecture which is resilient against any malicious server failure. Use of erasure coded techniques in the data distribution and preparation provides the redundancies and guarantees the data dependability. With the help of homomorphic token(HMAC) along with distributed verification of erasure-coded data, the proposed scheme almost guarantees the storage correctness and simultaneous localization of data errors in case of any data modification or corruption, i.e., the identification of the misbehaving server(s).