Exploring the integration of edge computing and blockchain IoT: Principles, architectures, security, and applications

IoT systems are widely used in various applications, including healthcare, agriculture, manufacturing, and smart cities. However, these systems still have limitations, such as lack of security, high latency, energy inefficiency, the inefficiency of bandwidth utilization, and shortage of automaticity. The integration of edge computing and blockchain into IoT has been proposed to address these limitations. Yet, this integration is challenging and has not been deeply investigated. This paper aims to conduct a review of the integration of edge computing and blockchain into IoT systems. To the best of our knowledge, this is the first review paper that covers all aspects of system architectures and categories of blockchain-based edge deployment, complete security requirements, including confidentiality, integrity, authentication, authorization/access control, privacy, trust/confidence, transparency, availability, secure automaticity, and tolerance, and applications of blockchain-based edge potential usages with consideration of security requirements. Additionally, this review provides comprehensive discussions of challenges and insights into the future direction of blockchain-based edge IoT systems. The review aims to serve as an entry point for non-expert readers and researchers to various aspects of blockchain-based edge IoT systems.