Traceable, Fair and Privacy-Preserving Decentralized Medical Data Exchange

To harness the commercial potential of medical data, various blockchain-based data-sharing and exchange platforms have been proposed. A key challenge is accurately tracing the provenance and transformations of medical data assets throughout the exchange process. Existing methods cannot facilitate exchanges of publicly hosted datasets while maintaining fairness, as they require revealing keys to the blockchain during interactions. This paper presents MEDET, a novel data exchange scheme that ensures traceability of medical data assets while protecting data privacy and guaranteeing exchange fairness. MEDET leverages zero-knowledge proofs to securely verify transformations within medical datasets and confirm data authenticity. Unlike previous schemes, MEDET supports both simple data exchanges and detailed tracking of data transformations and transaction histories, aiding in the provenance and value assessment of medical records. Additionally, MEDET features a key-secure protocol for fair exchange without disclosing symmetric keys. Compared to existing fair exchange schemes, MEDET uniquely ensures the privacy of publicly hosted data while simultaneously upholding the exchange fairness. The security analysis of MEDET demonstrates its security and privacy properties. The evaluation of MEDET indicates that it outperforms existing schemes in tracking data transformations and facilitating exchanges. © 2026 IEEE.