Secure and sustainable smart home networks with blockchain-based IoT framework for privacy and energy efficiency

Abstract Smart home networks are a rapidly evolving part of the Internet of Things (IoT), where connected devices exchange information to automate energy use, enhance comfort, and improve user safety. Despite their benefits, these systems face ongoing challenges related to data privacy, communication security, and eco-friendly energy management, especially when centralized control introduces risks such as single points of failure and delays. Existing solutions, including cloud-based encryption, blockchain-powered energy trading, and lightweight authentication, have improved trust and interoperability but still encounter issues related to scalability, high processing demands, and limited resistance to quantum threats. To address these limitations, this paper presents a blockchain-based system that enhances privacy, security, and energy efficiency in smart homes. The system integrates Machine-to-Machine (M2M) communication and IoT protocols are utilised and optimised within a decentralized architecture composed of communication, security, and application layers, making it modular and reliable. A flexible, post-quantum key exchange method based on the Supersingular Isogeny Diffie-Hellman (SIDH) protocol ensures device and user authentication. The system utilises a range of communication protocols, including WebSocket, UDP, and TCP, within the decentralised architecture to balance reliability and performance across different smart home applications. The design also introduces distinct access levels for users and administrators to strengthen control and support collaboration among neighbouring homes for collective energy savings. Tests conducted using Cisco Packet Tracer demonstrate notable performance improvements: approximately a 22% reduction in latency, an 18% enhancement in energy efficiency, and a 15% increase in throughput compared to traditional blockchain-IoT configurations. These results indicate that the proposed system provides a secure, scalable, and energy-efficient framework for the future of smart home networks.