A robust owner-to-user data sharing framework in honest but curious cloud environments

This paper proposes robust owner to user framework for secure data sharing in honest but curious cloud environments. The proposed framework presents a robust solution to accomplish the honest but curious cloud environments desired features such as data confidentiality, scalability, fine-grained data access, efficient user revocation, stateless cloud, preventing colluding users from accessing unauthorized data and generic construction. Furthermore, the proposed framework exploits the public key infrastructure (PKI) desired security features to provide an access control mechanism to prevent colluding users to access unauthorized data. Moreover, the proposed framework counters the attack of the rejoining of a revoked user authorized with different attributes to gain access to his previously authorized data. In addition, the proposed framework prohibits the collusion between an authorized user and a revoked user to possess the access privileges once assigned to the revoked user. This is accomplished with the aid of using dual signature technique. Moreover, the proposed framework capitalizes the existence of PKI to maximize the usage of offline operations to enhance the framework performance. Also, the proposed framework makes use of PKI to offer a secure transmission of private data and defends man in the middle attack. The implementation and the complexity analysis of the proposed framework express the framework practicability.