Blockchain-Based Security Framework for Internet of Things (IoT) Networks: A Layered Architecture, Consensus Analysis, and Application Study in the ECE Domain

The rapid proliferation of Internet of Things (IoT) devices across healthcare, industrial automation, smart agriculture, smart grid, and smart-city domains has magnified concerns surrounding data integrity, device authentication, and network resilience. Conventional client-server and cloud-centric IoT security models suffer from single points of failure, limited transparency, and poor scalability as the number of connected endpoints grows into the tens of billions. Blockchain technology, with its decentralized, immutable, and cryptographically verifiable ledger structure, has emerged as a promising complement to traditional IoT security mechanisms. This paper presents a comprehensive study of blockchain-based security for IoT networks from an Electronics and Communication Engineering (ECE) perspective. We review the layered architecture of IoT systems, identify dominant threat surfaces at the perception, network, edge, and application layers, and propose an integrated five-layer blockchain-IoT security architecture suited to resource-constrained embedded hardware. We present a comparative evaluation of consensus mechanisms — Proof of Work (PoW), Proof of Stake (PoS), Practical Byzantine Fault Tolerance (PBFT), Delegated Proof of Stake (DPoS), Proof of Authentication (PoAh), and Proof of Authority (PoA) — with respect to energy consumption, latency, and scalability for constrained IoT nodes. A threat model mapping common blockchain-IoT attack vectors to mitigation strategies is developed, along with case-study discussion of healthcare (IoMT), supply chain, and smart-grid deployments. The paper concludes with open research challenges — including scalability, interoperability, quantum-resistance, and regulatory alignment — and outlines future research directions relevant to hardware-software co-design in the ECE domain

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