Privacy-Preserving Blockchain-Based Data Sharing Platform for Decentralized Storage Systems

Cloud-based storage services have been the dominating outsourcing solution for both individuals and organizations to share data digitally. Despite the advantages, users must rely on storage services for data confidentiality, data access control, user privacy, and data availability. Whereas data confidentiality can be protected by advanced encryption algorithms, the rest remain challenging. First, in existing centralized storage services, even though data access controls are mainly defined by data owners, they are maintained and enforced by the services, which can deny data retrieval requests of authorized users or allow requests of illegitimate users. Second, the identity of a user is often known to the services to verify its eligibility to access requested data according to the access control, thus making the user traceable in the system. More importantly, the lack of anonymity may make users reluctant to use such services in sensitive contexts. Third, a huge amount of data is daily generated and stored on a centralized party, simultaneously serving requests from many users, which may cause a collapse of the system during peak periods. To address all these concerns, we propose a privacy-preserving blockchain-based data sharing platform for the InterPlanetary File System (IPFS), a content-addressable peer-to-peer storage system. The platform allows protecting both user anonymity, data confidentiality, and provides high data availability due to being deployed upon the IPFS network.