A Blockchain-Enabled Lightweight Boolean Multi-Keyword Search Scheme for Encrypted EHRs in Medical Cloud Environments

To tackle the growing need for efficient and fine-grained ciphertext access control and search capabilities in managing large-scale electronic health records (EHRs) within medical cloud environments, we propose a novel blockchain-enabled lightweight boolean multi-keyword search scheme. This cutting-edge solution integrates attribute-based access control with boolean multi-keyword search by embedding access structure within the index and incorporating search structures within the trapdoor. By harnessing the power of blockchain technology, our approach facilitates outsourced encryption, decryption, and search operations for EHRs, effectively eliminating the necessity for additional result verification. Through comprehensive security analysis and performance evaluation, we demonstrate that our proposed scheme not only exhibits robust security features but also significantly reduces computational, storage, and communication overhead when compared to the state of the arts. Notably, the computational overhead of index generation is reduced by at least 36.4%, underscoring the efficiency of our approach. Furthermore, our scheme achieves exceptional efficiency in smart contract execution, rendering it particularly suitable for resource-constrained devices in medical cloud environments.