# Blockchain Solutions for Enhancing Security and Privacy in Industrial IoT
## 3 Background
### Integrated Architectural Framework for Smart Industrial Systems  
The architecture presented in this work combines principles from the Industrial Internet of Things (IIoT) and smart factory systems to form a comprehensive framework that supports intelligent, secure, and efficient industrial operations. This integrated model draws from two foundational references: the IIC-IIRA (Industrial Internet Consortium Industrial Internet Reference Architecture) and the Korea Smart Factory Foundation Reference Model. By aligning these architectures, the system enables seamless data flow, real-time analytics, automation, and robust security across the multiple layers of an industrial ecosystem.  
At its core, and as shown in Figure 1A, the IIC-IIRA architecture follows a layered structure that facilitates both the vertical and horizontal integration of systems. The IIC-IIRA model defines three primary layers--enterprise, transport, and edge--each with distinct roles in managing data, processing logic, and device interaction. The enterprise layer serves as the strategic center, hosting high-level applications, analytics engines, and centralized data repositories. It ensures enterprise-wide coordination, decision making, and integration with external systems. Below it, the transport layer functions as an intermediary that orchestrates the communication between the upper enterprise systems and the lower edge and field devices. This layer handles data orchestration, local storage, and intermediate computation to support real-time responsiveness. At the lowest level, the edge layer operates at the physical-digital interface, where IoT devices collect data  
Figure 1: Smart factory architecture reference models and major cyberattacks.  
and edge nodes perform localized processing and control actions. This hierarchical design reduces latency, enhances autonomy, and improves bandwidth efficiency.  
Complementing this structure is the Korea Smart Factory Foundation Reference [27], as shown in Figure 1B, which emphasizes application-driven control, automation, and monitoring within a manufacturing context. In this model, the application system acts as the central intelligence hub, integrating AI-based analytics and issuing control commands based on operational insights. These commands are executed by the control automation layer, which comprises controllers and sensors responsible for regulating machinery and processes in real time. Concurrently, the monitoring/operation data component gathers information from IoT-enabled field automation systems and cloud services, feeding it back into the application layer for continuous optimization. A key aspect of this model is its explicit consideration of cybersecurity threats, identifying common attack vectors such as DDoS, MITM, code injection, and physical breaches. Security mechanisms are embedded throughout each layer to ensure the integrity, confidentiality, and availability of critical systems and data.  
Together, these models illustrate a cohesive architectural vision for next-generation industrial environments. They emphasize distributed data management, intelligent edge processing, cloud scalability, and secure communication. The integration of AI and advanced analytics allows for predictive maintenance, process optimization, and autonomous decision making. Moreover, the layered approach ensures modularity, adaptability, and interoperability across diverse technologies and platforms. By combining the structured rigor of the IIC-IIRA with the practical focus of the Korean smart factory model, this architecture provides a scalable foundation for deploying intelligent industrial solutions that meet evolving technological and operational demands.