Flexible and secure access control for EHR sharing based on blockchain

Abstract

With the rapid development of the healthcare industry, many Electronic Health Records (EHRs) have emerged in different healthcare centers. However, lots of personal medical data are stored directly in plaintext at a single healthcare center, which makes it suffer from the single point of failure and brings many security and privacy issues such as privacy information leakage or tampering. The combination of blockchain and attributed-based cryptography can effectively solve the above problems. Therefore, in order to enable flexible fine-grained access control and efficient data retrieval while achieving privacy protection, we employ the ciphertext-policy attributed-based encryption (CP-ABE) and ciphertext-policy attribute-based searchable encryption (CP-ABSE) to propose a hidden policy attribute-based access control scheme. In addition, we combine consortium blockchain and smart contract to provide secure and reliable search and outsourcing decryption. Finally, through the security analysis and experimental results, we demonstrate that our scheme is secure and efficient.