PureTrust: A Soulbound Token-Based Blockchain Framework for Incentive-Driven Trust Management in V2X Networks

Ensuring reliable trust management in vehicle-to-everything (V2X) networks is challenging due to the presence of malicious behavior and identity spoofing. This article proposes PureTrust, a blockchain-enabled trust management framework that integrates PureSBT, a soulbound token (SBT)-based incentive mechanism, for secure and nontransferable reputation tracking. PureTrust employs a hybrid trust computation model combining Bayesian estimation, cooperation decay, malicious behavior penalties, and temporal trust aging to generate adaptive trust scores. Built on PureChain with the proof of authority and association (PoA2) consensus, and interplanetary file system (IPFS)-based storage, the framework ensures scalability, transparency, and low on-chain overhead. The simulation results demonstrate that PureTrust achieves consistently high detection accuracy, maintains approximately 80% successful message delivery, and provides significantly higher throughput with a low average latency of 1.54 s compared to existing public and private blockchain networks. By securely binding reputation to vehicle identities via nontransferable SBTs and enabling issuer-controlled revocation, PureTrust incentivizes cooperation while effectively mitigating trust manipulation and reputation laundering-related risks.