Blockchain-Enabled Privacy-Preserving Medical Data Sharing with Verifiable Insurance Evaluation

Abstract

With the growing demand for secure medical data sharing and accurate insurance premium assessment, privacy, trust, and interoperability have become pressing challenges in healthcare digitalization. Existing solutions often suffer from centralized control, inflexible access policies, and weak privacy guarantees. To address these, we propose a blockchain-based, privacy-preserving scheme that integrates threshold proxy re-encryption and zero-knowledge proofs. Patients’ encrypted medical records are stored in private cloud environments, while access control is enforced through a threshold proxy re-encryption mechanism. Dynamic rekeying and delegation are supported through re-encryption key redistribution. For insurance verification, we generate zero-knowledge succinct non-interactive arguments of knowledge (zk-SNARKs) based on arithmetic circuits that represent the insurance policy requirements. These proofs are verified on-chain without revealing any underlying medical information. Security and performance analyses demonstrate the feasibility and efficiency of the proposed system. Experimental results show that our scheme supports sub-100 ms re-encryption cycles, reduces zero-knowledge proof generation time by over 90% compared to other zk-SNARK schemes, and imposes low on-chain computational overhead. These findings demonstrate the feasibility and potential suitability for real-world privacy-preserving medical data sharing and insurance evaluation.