A zero-trust decentralized architecture for heterogeneous IoT monitoring systems

Ensuring the integrity of infrastructures and the sustainability of the environment are critical tasks in today's society. Structural health and environmental monitoring are disciplines that aim to monitor these assets by trying to assess their condition and detecting potential issues. Over time, these activities have become increasingly dependent on the Internet of Things (IoT). This connection has allowed new capabilities to be introduced and brought these systems to work on large-scale environments. Unfortunately, this dependency also introduced several issues, such as centralization, lack of transparency, and interoperability, that weaken their reliability, which is essential for informed decision-making in the field. In this thesis we tackle these problems through a multi-layer, zero-trust decentralized architecture to enhance transparency, trustworthiness, and interoperability in monitoring systems. The architecture introduces an Interoperability Layer based on the W3C Web of Things (WoT) standard that enables a seamless integration among various IoT devices and platforms. Additionally, we introduce a Trustability Layer powered by ZONIA, a decentralized blockchain oracle system that ensures data integrity without relying on centralized entities or specialized hardware. ZONIA operates under a zero-trust paradigm, aggregating data from multiple sources and employing a truth inference algorithm and a reputation system to maintain system resiliency. We validated our approach through several evaluations of the components in these layers and through the development and deployment of a real-world structural health monitoring platform based on the proposed architecture.