车联云中节点的移动性、网络的动态性、通信方式的开放性和车辆的非可信性都给车联云中任务调度的安全性提出了很大的挑战。在充分考虑车联云特点的基础上引入了区块链，提出了一种适用于车联云中任务调度的轻量级区块链架构。利用路边单元（road side unit，RSU）构建区块链网络，采用改进的实用拜占庭容错（practical Byzantine fault tolerance，PBFT）算法完成共识。在建立该架构调度延时模型的基础上，通过实验对该架构的调度性能进行测试和分析。与以太坊的对比结果表明：该框架不仅实现了任务调度过程的不可抵赖性，避免了任务调度服务器的单点故障，提高了可用性，而且实现了轻量级，即无需消耗算力或额外存储空间也能达到毫秒级的调度延时。
The mobility of nodes in vehicular cloud, the dynamics of networks, the openness of communication methods, and the non-trustworthiness of vehicles bring more challenges to the security of task scheduling in vehicular cloud. Based on the full consideration of characteristics of vehicular cloud, this article introduces blockchain and proposes a lightweight blockchain architecture suitable for task scheduling in vehicular cloud. Road side units (RSU) are used to construct a blockchain network, and an improved practical Byzantine fault tolerance (PBFT) algorithm is used to complete the consensus. Based on the scheduling delay model of the architecture, the scheduling performance of the architecture is tested and analyzed through experiments. The comparison with Ethereum shows that the proposed architecture not only realizes the non-repudiation of the task scheduling process, avoids the single point failure of the task scheduling server, improves the availability, but also achieves lightweight, that is, no additional computing power or storage space is required, and can reach millisecond-level scheduling delay.
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