Blockchain-based multiple auditing scheme against cheating owner in clouds

Along with the commonplace of cloud outsourcing services, the problem of auditing the integrity of outsourced data without downloading has attracted much attention increasingly. However, in most existing auditing schemes, the audit only focuses on resisting undependable cloud server, rarely considers the problem of resisting cheating owner. An unreliable data owner may store the data not the same as it claimed for interest. Even worse, an undependable owner may deliver a sham message deliberately to avoid paying server for service or to cheat its deposit. To solve this problem, we propose a blockchain-based multiple auditable scheme against cheating owner by constructing a novel incremental structure, that allows for low computation and communication overheads, while providing a continuous natural flow of joint verification between storage parties over time. Specifically, our scheme is a two-way verification protocol that makes both parties consistently dependable. Besides, the incremental structure that uses a reversed recursive hash chain structure combined with blockchain and aggregate signature, makes our scheme more suitable for big data auditing. Smart contract is deployed to realize a central-free mechanism of rewards and penalties. The security analysis and simulation experiment demonstrate that the proposal is secure, dependable, efficient and practical.