CloudShare: Towards a cost-efficient and privacy-preserving alliance cloud using permissioned blockchains

Data explosion has raised a scalability challenge to cloud storage management, while spinning disk capacity growth rates will continue to slow down. Major data holders such as cloud storage providers with a heavy reliance on disk as a storage medium will need to orchestrate multiple kinds of storage to better manage their relentless data growth. In this paper, we first explore the scenario that multiple clouds are driven by interests to make the storage resources efficiently allocated without requiring a trusted third party, and then propose a novel model, called CloudShare, to enable multi-clouds to carry out a transparent encrypted data deduplication among cross-users via blockchain. Our scheme significantly reduces the storage costs of each cloud, and saves the upload bandwidth of users, while ensuring data confidentiality and consistency. We demonstrate via simulations on a realistic datasets that CloudShare achieves both the effectiveness and the efficiency.