This project aims to establish a secure and verifiable data sharing infrastructure with built-in security and privacy using blockchain technology. By storing and sharing encrypted digests of financial data on a blockchain platform, authorized institutions can properly trace historical transactions without relying on the involvement of third-party auditing. Our blockchain-based data sharing platform can break data silos in the present-day financial sector and boost the efficiency of a wide swath of services.

The main challenge of designing a blockchain-based data sharing platform is providing strong protection mechanisms to guarantee on-chain data confidentiality. Although applying standard encryption schemes can protect data privacy, it has become a challenging issue for users to search and share conveniently and efficiently over encrypted data. Meanwhile, as financial data usually contains rich content, it is often necessary to have more expressive searching algorithms. This is the dilemma between data confidentiality and data utility.

Another challenging issue for this project lies in the problem of query authorization relating to policy compliance. In practical deployment, query authorization refers only to authorized users who have access to data records. For example, in a likely scenario in credit assessment, authorized decision-makers’ access is limited to search within the applicant’s previous financial documents concerned with credit transactions. Query authorization needs to urgently address this issue.
We tackle these challenges from two directions: Firstly, for secure and efficient data sharing over the blockchain platform, we investigate a hybrid storage architecture where raw data is stored off-chain on dedicated storage servers and a secure index is kept on-chain for encrypted search. Secondly, for query authorization, we plan to design a fine-grained access control layer on top to safeguard data sharing with policy compliance.