A blockchain enabled IoT routing framework improving security and performance in smart cities

The rapid integration of Internet of Things (IoT) technologies into smart city infrastructures has enabled advanced urban services but also introduced significant challenges related to scalability, reliability, and security. Traditional routing protocols often lack robust mechanisms to ensure data integrity, defend against cyber threats, and maintain high performance in large-scale deployments. This paper presents a blockchain-enabled secure IoT routing framework designed to strengthen trust, enhance routing efficiency, and mitigate network attacks in smart city environments. The proposed framework integrates Hyperledger Fabric with Practical Byzantine Fault Tolerance (PBFT) consensus into the routing decision process, enabling immutable identity verification, consensus-approved route validation, and anomaly detection. Using NS-3 simulations, its performance is compared against three conventional protocols 6TiSCH, SDN-based routing, and ROLL across various network sizes and traffic scenarios. Evaluation metrics include throughput, end-to-end latency, packet delivery ratio (PDR), and resilience against blackhole and spoofing attacks. The results indicate that the blockchain-enabled framework can improve throughput by approximately 30%, reduce latency by up to 40%, increase PDR by up to 8% points, and significantly reduce successful security breaches compared to traditional approaches. These findings suggest that blockchain can provide secure, scalable, and high-performance IoT networking solutions for future smart cities.