H-PBFT: A Hierarchical and Credit-Aware PBFT Consensus Mechanism for Blockchain-Based Intelligent Transportation Systems

To address the risks of centralized single-point failures and data privacy leaks associated with massive data storage in Intelligent Transportation Systems (ITS) and Vehicle-to-Everything (V2X) environments, this paper proposes a distributed secure storage architecture based on blockchain. However, traditional Practical Byzantine Fault-Tolerant (PBFT) algorithms suffer from scalability bottlenecks in large-scale dynamic networks, such as high communication overhead and low consensus efficiency. Therefore, this paper designs a hierarchical and reputation-aware improved consensus mechanism (H-PBFT). First, this mechanism introduces a geographical location grouping strategy, dividing all network nodes into several local consensus groups and leveraging edge computing characteristics to achieve rapid consensus within each group. Second, a multi-dimensional reputation evaluation model (comprehensively considering historical behavior, performance, and availability) is constructed to dynamically elect representative nodes from each group to participate in global consensus, thereby significantly reducing the communication complexity from O(N2). Simulation results show that compared with standard PBFT, Q-PBFT, and APBFT, H-PBFT exhibits significant advantages in consensus latency, throughput, and view switching recovery time, and maintains high system robustness even in complex network environments with malicious nodes.