Secure and Efficient Stigmergy-Empowered Blockchain Framework for Heterogeneous Collaborative Services in the Internet of Vehicles

The Internet of Vehicles (IoV) is expected to address the significant problems of modern transportation through collaboration among various entities. It is crucial to establish a collaborative mechanism for untrusted entities to achieve the full potential of IoV. Blockchain is a promising solution for building a credible environment for entities. However, because of the difference and complexity of services, using a classical blockchain system to support heterogeneous collaborative services in IoV causes some challenges in smart contract support, system security, and computational efficiency. In this article, we propose a stigmergy-empowered blockchain framework called SEB, which enables untrusted IoV entities to perform heterogeneous collaborative services conveniently, securely, and efficiently. Specifically, we first explore the characteristics of collaborative services and analyze the challenges of existing blockchain systems. Furthermore, we introduce the stigmergy of swarm intelligence into blockchain and integrate the stigmergy into SEB by designing a new transaction data structure, a digital pheromone and transaction selection rules, and a new transaction selection algorithm. Simulation experiments demonstrate that compared with IOTA, SEB reduces smart contract transaction sorting searches by approximately 56%, increases the average chain length by up to approximately 87%, and decreases the computation time of the transaction selection algorithm by up to approximately 98%.