A fine‐grained and secure health data sharing scheme based on blockchain

Electronic health record (EHR) allows patients to use an open channel (ie, Internet) to control, share and manage their health records among family members, healthcare providers and other third party data users. Thus, in such an environment, privacy, confidentiality, and data consistency are the major challenges. Although cloud-based EHR addresses the aforementioned discussions, these are prone to various malicious attacks, trust management and non-repudiation among servers. Recently, due to the property of immutability, blockchain technology has been introduced to be as an auspicious solution for achieving EHR sharing with privacy and security preservation. Motivated by the above debates, we present BFHS, a blockchain-based fine-grained secure EHR sharing mechanism. On BFHS, we encrypt the EHR using ciphertext-policy attribute-based encryption (CP-ABE) and upload it to the interplanetary file system (IPFS) for storage, while the matching index is encrypted via proxy re-encryption and kept in a medical consortium blockchain. In addition, we created a credit assessment mechanism and incorporated it into the smart contract. Smart contracts, proxy re-encryption, a credit evaluation mechanism, and IPFS all work together to give patients with a trustworthy EHR sharing environment and a dynamic access control interface. The thorough comparison and experimental analysis show that the proposed BFHS has more comprehensive security features and is more practicable.