A Comparative Study of Security Protocols in IoT Communication Using Blockchain
International Research Journal of Modernization in Engineering Technology and Science · 2025
The Internet of Things (IoT) is one of the most revolutionary innovations of the 21st century, connecting billions of devices across domains such as healthcare, transportation, agriculture, and smart cities.These devices continuously generate and exchange sensitive data.However, lightweight IoT protocols such as MQTT (Message Queuing Telemetry Transport), CoAP (Constrained Application Protocol), and HTTP (Hypertext Transfer Protocol) were designed primarily for efficiency, not for security.This exposes IoT systems to risks like spoofing, replay, data tampering, and man-in-the-middle attacks.Blockchain, with its decentralised, immutable, and transparent ledger, provides a potential solution for enhancing trust and integrity in IoT data exchange.This paper presents a comparative study of MQTT, CoAP, and HTTP when integrated with blockchain.The evaluation considers latency, throughput, energy consumption, and resistance to attacks using both simulation and Indian case studies.The findings indicate that MQTT integrated with blockchain achieves the lowest latency (35 ms) and highest throughput (490 kbps), making it most suitable for real-time healthcare and smart city applications.HTTP with blockchain, although slower, offers stronger resistance to tampering and is better suited for financial and egovernance contexts.CoAP with blockchain provides balanced performance, particularly beneficial for rural and agricultural IoT applications, where low energy use is critical.This research contributes to both academia and industry by offering a framework for protocol selection in blockchain-enabled IoT systems, highlighting trade-offs between speed, trust, and energy consumption.It also provides insights for Indian policymakers working on initiatives such as Digital India and the Smart Cities Mission, where secure IoT adoption is essential.However, the very nature of IoT-billions of small, resource-constrained devices exchanging sensitive information-creates serious security challenges.Conventional IoT communication protocols (MQTT, CoAP, HTTP) were designed for low bandwidth and efficiency, not for high-level security.For example: MQTT is fast but lacks encryption and integrity features. CoAP is lightweight but vulnerable to spoofing and replay attacks. HTTP, while more secure, consumes high bandwidth and energy, making it unsuitable for constrained IoT devices.This raises a critical question: How can IoT data transmission be made secure, trustworthy, and tamper-proof without compromising efficiency?