Blockchain-based medical data proxy re-encryption access control scheme

The proper use of medical data plays a vital role in the development of medical research. However, there are challenges related to privacy leakage in medical data sharing and the controllability of data by patients during its use. To address these issues, this study proposes a blockchain-based scheme for controlling access to medical data. Firstly, a medical data sharing scheme based on blockchain is constructed, incorporating a medical data sharing scheme based on proxy re-encryption. This solution achieves secure sharing of medical data while protecting the privacy and security of patient medical data through proxy re-encryption technology, with consensus nodes acting as proxy nodes responsible for proxy re-encryption. Secondly, a mechanism for dynamically adjusting data access permissions is designed. Access control policies are stored in smart contracts, allowing patients to interact with smart contracts to update medical data access permissions by modifying attribute lists, thereby achieving controllable sharing of medical data by patients. Finally, security analysis indicates that the proposed scheme can protect medical data privacy, enable dynamic data sharing, and resist collusion attacks. Performance analysis shows that the scheme has advantages in terms of communication overhead and computational costs, making it suitable for controlled data sharing between patients or hospitals and research institutions.