Zero Trust Architecture for IoT and Smart Environments: A Systematic Literature Review

Abstract

Zero Trust Architecture (ZTA) has emerged as a promising security paradigm to address the limitations of perimeter-based defenses in increasingly distributed and heterogeneous computing environments. The rapid growth of Internet of Things (IoT) and edge systems introduces challenges related to scalability, resource constraints, and continuous trust enforcement that traditional enterprise-oriented Zero Trust models fail to fully address. This paper presents a systematic literature review (SLR) of Zero Trust Architecture research for IoT and smart/edge environments, following the PRISMA 2020 protocol, with a fully reported and reproducible identification-to-inclusion pipeline (412 records identified, 19 selected studies retained). Nineteen selected studies published between 2018 and 2026 – comprising both primary technical contributions and secondary research syntheses retained as secondary research studies evidence – were synthesized through thematic classification and a study-wise quality assessment across architectural models, accesscontrol mechanisms, trust and risk evaluation, IoT constraint handling, and validation approaches. The analysis reveals a strong emphasis on architectural design and policy-based enforcement, while lightweight deployment, SOHO-scale applicability, and real-world validation remain underexplored. Based on the identified gaps, this review highlights key research directions for developing practical, resource-efficient Zero Trust frameworks tailored to constrained IoT environments.