BLOCKCHAIN-BASED CYBERSECURITY FRAMEWORK FOR INTERNET OF THINGS NETWORKS: CHALLENGES, APPLICATIONS AND FUTURE DIRECTIONS

The Internet of Things (IoT) has emerged as an important technological paradigm that connects physical devices, sensors, machines, and software platforms through communication networks. IoT systems are increasingly used in smart homes, healthcare, industrial automation, agriculture, transportation, energy management, and smart cities. However, the rapid expansion of connected devices has created significant cybersecurity challenges. Conventional centralized security architectures may suffer from single points of failure, scalability limitations, privacy concerns, and difficulties in managing large numbers of heterogeneous devices. Blockchain technology provides a decentralized approach that can strengthen trust, data integrity, authentication, and transaction transparency in IoT environments. This paper presents a comprehensive review of blockchain-based cybersecurity for IoT networks. It examines the fundamental characteristics of blockchain, major IoT security threats, blockchain-based authentication mechanisms, decentralized data management, smart contracts, privacy preservation, and integration with artificial intelligence. The paper further discusses challenges related to computational resources, scalability, latency, energy consumption, interoperability, and blockchain storage requirements. A conceptual blockchain-IoT security framework is proposed in which IoT devices communicate with trusted edge or gateway nodes while blockchain mechanisms provide decentralized verification and tamper-resistant records. The study also discusses applications in healthcare, smart cities, agriculture, industrial IoT, and intelligent transportation. Finally, future research directions including lightweight blockchain, AI-assisted threat detection, privacy-preserving technologies, and quantum-resistant security are discussed.