Blockchain-based attribute-based keyword searchable encryption for health cloud system.

The application of electronic information technology in medical treatment has become more and more popular, but there are also many challenging problems, exemplified by data forgery and tampering in data sharing. This paper proposes a blockchain-based attribute-based keyword searchable encryption scheme for health cloud systems, which solves some problems of privacy disclosure and data tampering in data sharing. Firstly, by using attribute-based encryption with keyword search technology, users can share search capabilities in a fine-grained way, and if their attributes are changed, their access permission will be revoked in time. Besides, we introduce blockchain and digital signature technologies to ensure the correctness and integrity of data. We encrypt the access policy to prevent privacy disclosure in the access structure. Finally, security analysis and simulation experiments show that our scheme is secure and effective, and the efficiency of search is improved by approximately 40% compared with ABKS-HD.