Security Trade-Offs in Lightweight Consensus Mechanisms for IoT-Blockchain Integration

Abstract

The rapid proliferation of Internet of Things (IoT) ecosystems has intensified the demand for decentralized, secure, and scalable data management frameworks. Blockchain has emerged as a promising solution; however, its conventional consensus mechanisms are computationally expensive for resource-constrained IoT nodes. This paper investigates the performance and security trade-offs associated with lightweight consensus mechanisms—namely Practical Byzantine Fault Tolerance (PBFT), Proof-of-Authority (PoA), and Proof-of-Elapsed Time (PoET)—which are increasingly adopted in next-generation IoT-blockchain systems. A comparative framework is established to evaluate communication latency, throughput, fault tolerance, and attack resistance. Real-time simulation experiments were conducted using smart city traffic sensors and healthcare monitoring IoT architectures to assess the practical implications of these consensus protocols. Findings reveal that PBFT delivers strong security guarantees but faces scalability limitations under large peer counts, while PoA provides low latency with reduced decentralization. PoET offers energy efficiency but relies on trusted execution environments, introducing hardware-based vulnerabilities. The study highlights that selecting an appropriate consensus mechanism requires balancing resource constraints, trust assumptions, and domain-specific security requirements. Insights derived from this investigation will assist researchers and system architects in designing optimized and secure IoT-blockchain deployments.