| dc.description.abstract | It is an important security issue on how to guarantee the correctness of traffic information. The public key infrastructure of VANETs ensures secure transmission and prevents malicious tampering and falsification from outsiders, but it does not prevent attacks from insiders. Furthermore, the reputation system can mitigate these internal attacks, but the security of the system itself and the decentralized architecture of VANTs make the implementation difficult. The blockchain can exactly solve these problems. It is suitable for decentralized architectures, assuring both the correctness and tamper resistance of chaining data through a consensus mechanism.
This dissertation proposes a two-way event validation process to verify the correctness of the accident by different surrounding nodes or road facilities. Design a Proof-of-Event consensus protocol for VANETs to decide on the validity of traffic events by dynamically adjusting the majority decision. Moreover, the deep learning algorithm is applied to estimate the majority threshold of different situations to increase the accuracy of event validation. After obtaining the majority of the consensus within the scope of the accident, the evidence is written into the local blockchain, so that the information can be shared in the zone with anonymity. When the data is linked to the global blockchain, the validity of the pseudonyms is verified by the law enforcement agencies via the smart contract to ensure the correctness of the shared information and increase the trustworthiness of the evidence.
The simulation results show the proposed mechanism can effectively feedbacks traffic events. In a freeway hotspot, if the threshold is less than 60 veh/min, the accuracy is over 97.21%. If the percentage of malicious nodes is 30%, the false event success rate is only 12.23%. It can be proved that this dissertation can guarantee the correctness of traffic incidents through the proposed consensus protocol. Coupled with the design of the local evidence blockchain and the smart contract, the falsified events are filtered through the pseudonym identification contract. Then, the results are deployed to the global blockchain. This methodology provides a trust verification for tracking evidence, which can effectively restrain tampering and forgery from external or internal nodes.
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