Blockchain-Based Distributed Trust Model for Secure IoT Communication

As the Internet of Things (IoT) continues to grow, ensuring secure and trustworthy communication among distributed, resource-constrained devices remains a critical challenge. This paper introduces a Blockchain Based Distributed Trust (BDT) model designed to address the limitations of conventional trust mechanisms such as Public Key Infrastructure (PKI) and Proof of Work (PoW). Unlike PKI, which suffers from centralized trust bottlenecks, and PoW, which imposes excessive computational and energy burdens, BDT employs a lightweight, decentralized consensus mechanism optimized for IoT environments. By integrating an Exponentially Weighted Moving Average (EWMA) based trust score and edge level anomaly detection, BDT supports real time trust updates without reliance on central authorities. Experimental evaluation demonstrates that BDT offers substantial performance gains over PKI and PoW across key metrics. Specifically, BDT reduces communication overhead by 82.5% compared to PKI and 99.97% compared to PoW. It also achieves over 90% reduction in latency overhead relative to both alternatives. In terms of storage efficiency, BDT lowers storage requirements by 3.6% compared to PKI and 6.9% compared to PoW. Moreover, BDT maintains a false positive rate (FPR) below 3%, representing a reduction of approximately 40% compared to PKI and over 65% compared to PoW, even under high-intensity threats such as Sybil, MitM, and Replay attacks. These findings confirm that BDT offers a scalable, privacy preserving, and energy efficient trust model, delivering robust security without compromising performance making it a superior alternative to traditional PKI and PoW systems for real-time IoT applications.