Practical Byzantine Fault Tolerance-based Robustness for Mobile Crowdsensing

Abstract

Mobile crowdsensing (MCS) has become a prominent paradigm to collect and share data based on sensing devices with built-in sensors in the Internet of Things (IoT) era. Nevertheless, conventional MCS confronts various security and privacy vulnerabilities in terms of decentralized, openness, and non-dedicated properties. Currently, the submitted tasks are collected and managed conventionally by a centralized MCS platform. A centralized MCS platform is not safe enough to protect and prevent tampering sensing tasks since it confronts the single point of failure which reduces the effectiveness and robustness of MCS system. Meanwhile, fake task attack is a serious threat as it would drain excessive resources from the participant devices and clog the MCS servers to disrupt the services offered by the MCS. In order to address the centralized issue and identify fake tasks, a blockchain-based decentralized MCS is designed. Integration of blockchain into MCS enables a decentralized framework. Moreover, the distributed nature of a blockchain chain prevents sensing tasks from being tampered. The blockchain uses a Practical Byzantine Fault Tolerance (PBFT) consensus that can tolerate 1/3 faulty nodes, making the implemented MCS system robust and sturdy. In addition, an ensemble learning approach is deployed in the blockchain for eliminating fake tasks by malicious requesters. The evaluation test is conducted under two different datasets representing a big city and a small one to have an MCS campaign. Numerical results show that the ensemble approach eliminates most of the fake tasks with a detection accuracy of up to 0.99. Furthermore, the ensemble learning-integrated system outperforms individual learner-based centralized systems, and non-fault tolerance systems in terms of Ratio of Legitimate tasks ( RoLT ) saved and Ratio of Fake Tasks ( RoFT ). RoFT is low to 0.01, and RoLT is high up to 0.913 via the proposed MCS blockchain-driven framework.