Zero Trust Architecture for Industrial IoT Networks

Abstract

Industrial Internet of Things (IoT) networks connect sensors, programmable logic controllers (PLCs), supervisory control and data acquisition (SCADA) systems, enterprise platforms, and cloud services to support automation, monitoring, predictive maintenance, and data-driven decision-making. This connectivity also expands the attack surface of operational technology (OT), particularly where legacy equipment, remote access, heterogeneous protocols, and stringent availability and safety requirements coexist. This paper develops a Zero Trust Architecture (ZTA) tailored to IIoT environments. The proposed architecture combines strong device and user identity, continuous verification, least-privilege and attribute-based access control, micro-segmentation, secure gateways for legacy devices, encrypted communication, continuous monitoring, and risk-adaptive policy enforcement. A simulation-oriented evaluation framework is specified using a representative industrial network comprising field devices, PLCs, SCADA/HMI systems, an edge gateway, enterprise resources, and a remote maintenance user. The evaluation is designed to compare authorized and unauthorized access, lateral-movement attempts, malicious commands, and controller or gateway failures using security and performance metrics. The architecture is intended to contain compromise while preserving the availability and timing requirements of industrial processes. Importantly, the manuscript distinguishes the proposed evaluation framework from experimentally measured results: numerical performance values are not presented as empirical findings unless generated by an executable testbed. The study concludes that Zero Trust is most practical in IIoT when implemented incrementally, with OT safety and availability treated as first-class requirements and legacy assets protected through compensating controls rather than forced modernization.