Scalable blockchain architectures for enhancing integrity and privacy in Vehicular Ad-hoc Networks

Abstract

Vehicular Ad-hoc Networks (VANETs) are a cornerstone of intelligent transportation systems, enabling real-time communication and coordination among vehicles to improve traffic safety and efficiency. However, VANETs face significant challenges due to their inherent high mobility, dynamic topology, and varying network densities, which complicate the reliable management of data integrity, privacy, and decentralisation. Current solutions often struggle to balance these factors, particularly in high-density and high-mobility scenarios. This thesis aims to address these challenges by developing a scalable blockchain architecture that leverages advanced consensus mechanisms, privacy-preserving techniques, and dynamic sharding to meet the unique demands of vehicular networks.
To achieve this, the research introduces Proof-of-Mobility (PoM), a novel consensus algorithm designed to utilise vehicle mobility patterns to ensure data integrity while maintaining decentralisation and scalability. PoM is particularly effective in dynamic environments, demonstrating a 70.63% increase in blockchain data transmission efficiency and a 64.91% reduction in redundant data compared to conventional Proof-of-Stake (PoS) algorithm in high-density and high-mobility scenarios. By leveraging mobility as a key factor, PoM adapts seamlessly to dynamic vehicular environments, ensuring a more context-aware and efficient consensus process. This innovation addresses a critical gap in existing blockchain systems, which often fail to consider the fluid nature of VANETs.
Privacy and resource efficiency are further improved by integrating aggregated zero-knowledge proofs (ZKPs) within the architecture. This innovation reduces on-chain computation and storage costs by 90% compared to traditional methods, significantly optimising resource utilisation while preserving data confidentiality. Aggregated ZKPs enable secure data validation, ensuring that the system is suitable for real-time applications in vehicular communications.
The thesis further introduces a blockchain-based dynamic data sharding system that combines PoM and aggregated ZKPs to optimise data processing efficiency and scalability. This system dynamically allocates resources across shards and utilises ZKPs to enhance cross-shard validation, reducing its complexity to O(1). Comparative performance analyses highlight the system outperforms in throughput and bandwidth consumption, achieving a 90.8% reduction in bandwidth requirements compared to Merkle tree-based solutions. Dynamic sharding further ensures that the system can scale to accommodate an increasing number of vehicles without compromising performance, a critical requirement for next-generation intelligent transportation systems.
To validate the scalability, efficiency, and practicality of the proposed system, extensive simulations were conducted using tools such as OMNeT++, SUMO, INET Framework, Python, and OpenStreetMap. These experiments encompassed diverse scenarios, including urban (Ningbo City), rural, highway, and Manhattan grid maps, each with varying vehicle densities to test the system's adaptability to different network conditions rigorously. Real-world vehicular movement data from three distinct areas along Ningbo highways were also integrated to validate the reliability of the simulations. This approach ensured that the simulated environments closely mirrored actual conditions, providing robust evidence of the system's applicability in real-world vehicular networks.
The novelty of this work lies in its holistic integration of mobility-aware consensus algorithms, privacy-preserving cryptographic techniques, and adaptive sharding mechanisms into a unified blockchain framework tailored for vehicular networks. Unlike existing solutions, which often focus on isolated aspects, this thesis delivers a cohesive and scalable architecture capable of addressing the multifaceted challenges posed by VANETs. The proposed blockchain architecture excels in reducing communication bandwidth, improving data processing efficiency, and enhancing system security. These improvements are achieved while maintaining the inherent decentralisation and trustworthiness of blockchain technology. The findings of this thesis highlight the potential of the proposed architecture as a robust, scalable, and practical solution for intelligent transportation systems, capable of addressing the growing demands of future vehicular networks. Furthermore, the results have broader implications for integrating blockchain technologies into other dynamic and high-mobility systems, providing a foundation for future research and development.

Date of Award	Jul 2025
Original language	English
Awarding Institution	University of Nottingham
Supervisor	C.F. Kwong (Supervisor), David Chieng (Supervisor) & Pushpendu Kar (Supervisor)