## 3 Proposed Approach
[PERSON]'s model strengthens defense mechanisms by incorporating structured methodologies for human factor analysis, including monitoring insider behavior patterns and assessing social engineering susceptibility, thereby enhancing the robustness of the five-layer structure by addressing human-centric vulnerabilities at each security level [36; 37]. This enhanced approach can guide future adaptations of multi-layered models for energy infrastructure. Compared to other commonly implemented defense strategies, such as perimeter-focused or single-layer defense models, the layered defense strategy employed in this study offers significant advantages in flexibility and robustness. Single-layer strategies often rely heavily on perimeter defenses (e.g., firewalls) and risk rapid system-wide compromise when breached. By contrast, this layered approach includes redundancy across multiple points of defense, enabling the system to withstand partial breaches without compromising the entire infrastructure. For example, while firewalls are the primary defense in perimeter-focused strategies, here, intrusion detection and response mechanisms embedded in the application layer allow threats to be isolated and managed beyond the initial perimeter. Furthermore, [PERSON]'s human-centered approach is integrated, incorporating 'cyber persona' analysis to detect insider threats--a critical vulnerability often overlooked in traditional defense models. * In a single defense strategy, if an external intrusion occurs, the entire system quickly becomes compromised. In contrast, a layered defense architecture allows different layers to detect and block various types of threats, ensuring that even if an attack bypasses one layer, other layers can still provide a barrier. * For example, if the network layer is compromised, additional security measures in the application layer, such as security protocols and IDSs, can provide further protection. This creates a multi-layered defense system; yet, additional refinements, such as integrating predictive analytics and human threat monitoring at each layer, may improve resilience against attacks. [PERSON]'s framework suggests that adopting additional analysis-oriented layers enhances robustness. Figure 1 shows the layered security architecture that illustrates the role of each security layer in protecting energy infrastructure systems. This architecture is divided into five distinct layers, ranging from the physical layer to the security layer, with each layer responsible for safeguarding specific components of the system. Each layer operates independently but is interconnected, forming a comprehensive, multi-layered defense system that provides protection against various potential threats. The physical layer secures physical infrastructure such as power plants and power grids, focusing on hardware and equipment. The control layer ensures the security of control systems such as SCADA and SIS, making sure these systems operate safely. The network layer is responsible for securing the communication networks where data transmission occurs. The application layer defends software-based systems, such as SCADA and SIS, from malware and other cyber threats. The security layer includes mechanisms such as firewalls and IDSs that protect the entire system from external intrusions. The greatest advantage of a layered security architecture is that each layer provides independent protection while simultaneously interacting with other layers to form a multi-tiered defense. Each layer has a specific role in defending against particular threats, making this model stronger than a single-layer defense. For instance, even if the physical layer is breached, the control, network, and application layers can still provide additional protection, preventing a single intrusion from compromising the entire system. In contrast to a single defense strategy, where failure at one point can have catastrophic consequences, a layered approach enhances system resilience by allowing each layer to detect and mitigate threats independently.