DATA SECURITY IN CLOUD STORAGE USING FULLY HOMOMORPHIC ENCRYPTION

Cloud computing is the long dreamed vision of computing as a utility, where users can remotely store their data into the cloud so as to enjoy the on-demand high quality applications and services from a shared pool of configurable computing resources. The feature of the cloud services is that users' data are usually processed remotely in unknown machines that users do not own or operate which inevitably poses new security risks towards the correctness of the data in cloud. To overcome the problem previous approach introduced homomorphic token and distributed erasure-coded data. In the homomorphic computation they performed only one operation on inputs. So the hacker is possible to recover original inputs or plaintext. A fully homomorphic encryption method is proposed to support both addition and multiplication operations hereby preserving the ring structure of the plaintexts. It's effectively allowing the construction of programs which may be run on encryptions of their inputs to produce an encryption of their output. Since such a program never decrypts its input, it can be run by an untrusted party without revealing its inputs and internal state. The auditing result not only ensures strong cloud storage correctness guarantee, but also simultaneously achieves fast data error localization, the identification of misbehaving server. In this paper, we investigate the problem of data security in cloud data storage, which is essentially a distributed storage system. To achieve the assurances of cloud data integrity and availability and enforce the quality of dependable cloud storage service for users, we propose an effective and flexible distributed scheme with explicit dynamic data support.