Blockchain-Assisted Secure Data Sharing Protocol With a Dynamic Multiuser Keyword Search in IIoT

The Industrial Internet of Things (IIoT) and cloud computing have developed rapidly in recent years. Many enterprises are willing to outsource lightweight devices’ industrial data via the cloud to lower manufacturing costs and enhance production efficiency. The data sharers, however, usually have concerns about the security and privacy of their data stored in cloud outsourcing systems. Traditional certificateless searchable encryption primitives are tough to realize dynamically revocable and high-efficiency decryption. Furthermore, data sharing on untrusted devices may cause a single-key exposure problem. To address these issues, we propose a blockchain-assisted secure data-sharing protocol with a dynamic multiuser keyword search (DMUKS) in IIoT, which utilizes blockchain-assisted techniques to solve a single-key exposure problem and to realize fast certificateless keyword search as well as dynamic user and key management. The proposed DMUKS scheme enjoys minor computation and communication overheads. It maintains a constant ciphertext and trapdoor query size as users increase and supports user addition and revocation. Moreover, it periodically supports key and ciphertext updating and is secure against keyword-guessing attacks under the random oracle model. The performance comparison and analysis demonstrate that it is more efficient and flexible than the existing data sharing with keyword search schemes.