Fault tolerant public auditing system in cloud environment

Outsourcing the data onto the cloud has gained immense popularity because of the benefits that it provides. The responsibility of protecting that data is given to cloud storage provider. Meanwhile, it is prime concern of data owner to verify if the data is in the right form in the cloud, it is extremely burdensome if data owner carries out the audit of outsourced data and repairs the corrupted data and authenticators by himself. In earlier schemes, fully trusted third party auditor (TPA) carries out the verification process. But trusting TPA fully isn't the right idea. So, we introduce semi trusted TPA for verification where, in case it generates biased(wrong) results with respect to data stored on cloud, data owner will be intimated by proxy about it, so that data owner can inform cloud service provider. To carry out the repair of corrupted blocks of data and authenticators, we use proxy, which is also semi trusted and has the privilege to regenerate authenticators. All this is automated and done in the absence of data owner. Since the sole idea of this scheme is to relieve the data owner off the additional responsibility of data verification and repair, this technique is a big help to data owner.