Research on Multi-level Location Privacy Protection for Mobile Crowd Sensing based on Blockchain.

To address the leakage problem of user location privacy in mobile crowd sensing, a blockchain-based multi-level location privacy protection scheme for mobile crowd sensing is proposed. It uses private chains to decentralize user transaction records. Combined with the order-preserving encryption algorithm and the multi-level privacy cost mechanism, the server can allocate task rewards even when the users’ personalized location privacy is protected. Smart contracts are adopted to realize workers’ autonomous choice of tasks and ensure safe and fair transactions. Through experimental analysis and verification, the proposed scheme not only achieves anonymity, confidentiality, verifiability, and anti-tampering, but also prevents link attacks. Compared with the average reward allocation mechanism, the proposed probability reward distribution mechanism has improved the success rate of task allocation by 15.1%. In addition, the encryption and decryption computation cost is lower than that of related advanced schemes.