Access Control Mechanism for Cloud Data Using Block Chain and Proxy Re-Encryption

Abstract

This paper studies block chain and proxy re-encryption methods in our system. Block chain provides transparent property and serves privacy and confidentiality to the system. The storage of block chain can be a barrier for implementing the records in the system. Moreover, it is difficult to store the large amount of data exceeding into the practical storage capabilities of the current block chain usages. The most important issues of block chain are the performance, limited storage, privacy, energy consumption and scalability. Using normal public-key encryption, User A (data owner) needs to download and decrypt the requested data and then re-encrypts data using the target user’s public key. This process requires extra computation cost and communication to the data. Another solution for this is to allow data owners to define access policies and encrypt the data with encryption under the access policies; only authenticated users whose keys are matching their policies can decrypt the ciphertext. But the thing is here data owner needs to download, decrypt, and re-encrypt the requested data in case data access policies change dynamically and frequently. To overcome these drawbacks, in this paper our system proposed a proxy re-encryption scheme that gives solutions for securing data and sharing in cloud computing environment. This system will reduce communication cost and extra computational cost.