# Augmented Reality and the Digital Twin: State-of-the-Art and Perspectives for Cybersecurity
## 4 Perspectives for Cybersecurity
### Blueprint Architecture for DTs with AR in Security  
To enable all these benefits in the coming age of CPS, it is necessary to have a clear vision of the underlying conceptual architecture. In this section, we discuss a high-level concept based on the general academic architecture described in Section 3.3.3 and first concepts from practitioners [73]. The concept we introduce is not a technical architecture but, rather, an abstract blueprint for respective architectures. This blueprint is displayed in Figure 6 and shows how an AR-powered DT approach can be intertwined into modern cybersecurity architectures. In terms of architecture, the application of AR and the DT for cybersecurity especially comes into play in the _Application Layer_ (see Figure 6). While the _Physical Layer_ might provide security-relevant data (e.g., system logs or network traffic) to the _Digital Twin_, the real benefit for security can be provided when the DT is utilized for security applications. Typically, these security-relevant functionalities manifest in the application layer, where information from the DT is retrieved and analyzed. AR, as part of the _Presentation Layer_ on top of the application layer, finally, provides a visual representation for this information and enhances the security applications through its augmentation potential. **Physical Layer:** The foundation of the architectural blueprint is the physical layer, where the real-world system (i.e., real twin) under consideration is operating. Within this layer, the real-world system data originates. From a security perspective, we differentiate between two types of data relevant to any security measure: Dynamic data, such as logs, sensor data, or network traffic data, which is produced continuously; and Static data, which occurs rather non-frequently and primarily describes the physical system, e.g., its topology, configurations, etc. **Digital Twin:** Through its replication mode, the DT aims to mirror the current events in the real-world twin and induce the same states virtually as are present in the real-world counterpart. Thus, the DT layer's data lake is continuously synchronized with the most recent data from the physical layer. Additionally, the collected information is enriched with semantics and ontologies to give context to the data. On this basis, the Digital Twin can build models to represent the real-world system virtually. With these models, it can run in different operation modes. The analysis mode is mainly based on dynamic data to  
Figure 6: Conceptual architecture for AR-DT combination in cybersecurity. conduct analytical operations, such as predictive maintenance or anomaly detection. The simulation mode allows testing scenarios that might occur in the future (e.g., an attack or the implementation of another sub-component). Such simulations could, for instance, help to build a cyber range. With these functionalities, the DT is a crucial component to enable situational awareness in its full meaning. **Application Layer:** The first two layers of this concept (i.e., Physical Layer and Digital Twin) are universally applicable for any use case of the AR-DT combination. However, the application layer of the conceptual architecture is highly dependent on the use case. When applying the AR-DT combination for cybersecurity use cases, the application layer holds all necessary security measures. Security Information and Event Management (SIEM) systems, Intrusion Detection (IDS), Intrusion Prevention Systems (IPS), etc., can be connected to the DT via respective interfaces to evaluate and ensure the security posture of CPS. Although these security systems might also rely on other data sources, the DT will become a crucial part of CPS-oriented security analytics. Besides the aforementioned system, other security-oriented tools might be applied in this layer. One of them is training- and education-oriented security applications, such as cyber ranges built under the use of the DT.