A Review on Blockchain based secure communication for IoT Devices

The Internet of Things (IoT) connects a massive number of heterogeneous devices that exchange sensitive data over open networks, making security, trust, and privacy critical challenges. Conventional centralized security models suffer from single points of failure, limited scalability, and vulnerability to cyberattacks such as data tampering, spoofing, and unauthorized access. To address these limitations, this review paper presents a comprehensive analysis of blockchain-based secure communication approaches for IoT systems. It systematically examines existing architectures, consensus mechanisms, authentication schemes, access control models, and data integrity solutions proposed in recent literature. The study categorizes blockchain-IoT integration techniques based on network type, security objectives, and performance constraints, with particular emphasis on lightweight and energy-efficient solutions suitable for resource-constrained IoT devices. Furthermore, the paper highlights key challenges such as scalability, latency, interoperability, storage overhead, and privacy concerns. By identifying research gaps and open issues, this review provides valuable insights into future research directions and design considerations for developing scalable, secure, and efficient blockchain-enabled IoT communication frameworks. The findings serve as a useful reference for researchers and practitioners aiming to enhance trust