Decentralized Zero-Trust Authentication Framework for Edge-Enabled Industrial Internet of Things (IIoT) Using Smart Contracts

The proliferation of Industrial Internet of Things (IIoT) architectures has significantly expanded the attack surface of critical manufacturing infrastructures, rendering traditional perimeter-based security models obsolete. Centralized authentication mechanisms frequently introduce single points of failure, latency overheads, and vulnerability to advanced persistent threats. This paper introduces TrustChain-IIoT, a decentralized, zero-trust identity verification and access management framework leveraging private Ethereum-compatible smart contracts and lightweight cryptographic primitives. The proposed architecture replaces static credentials with dynamic, reputation-weighted cryptographic tokens issued at the edge gateway layer. Real-world benchmark simulations across an emulated smart factory network demonstrated that TrustChain-IIoT processes cross-device authentication requests within 42 milliseconds while mitigating up to 99.4% of simulated Man-in-the-Middle (MitM), replay, and Sybil attacks. The empirical results demonstrate that decentralized zero-trust paradigms provide scalable, tamper-resistant access control without compromising the real-time operational constraints of mission-critical industrial ecosystems.