Privacy Preserving Access Control Policies Using Two Level Encryption In Public Cloud

Abstract

With many features of cloud computing, many organizations have been considering moving their information systems to the cloud storage. Cloud storage is a service model, in which data is stored, maintained, managed and backup remotely, And made available to the users over the network. However, an important problem in public cloud is preserving confidentiality of stored data from both unauthorized access and the storage provider i.e. cloud. So, in order to make confidentiality the data owners first encrypts the file before uploading them on the cloud storage, and re-encrypting whenever user credentials change .That thus incur high communication and computational cost. We propose an approach based on two level encryption. Under such approach the data owner performs coarse grained encryption before uploading to the cloud server, and then cloud performs complete access control policy encryption on top of the encrypted data by the owner. Our system handles both confidentiality of data and preserves privacy of users from unsecured cloud.