Enforcing Event Concealment in Discrete Event Systems with Partial Observation

Core Concepts

A defensive function can be used to enforce the concealment of secret events in a discrete event system with partial observation, even when the system is unconcealable without the defensive function.

Abstract

The content discusses the problem of event concealment and concealability enforcement in discrete event systems (DESs) modeled as non-deterministic finite automata under partial observation.
Key highlights:

The authors introduce the notion of event concealment, where certain events are deemed secret and the goal is to hide their occurrences from an external eavesdropper.
They define concealability, which characterizes the ability of the system to hide the occurrences of secret events, and provide a necessary and sufficient condition for concealability based on a diagnoser construction.
When the system is unconcealable, the authors propose a defensive function that can be placed at the interface of the system with the eavesdropper to manipulate the observations generated by the system through event deletions, insertions, or replacements.
The authors define the notion of C-enforceability, which captures the ability of the defensive function to conceal the occurrences of secret events perpetually, regardless of the system's activity.
They provide a polynomial complexity construction to obtain one necessary and one sufficient condition for C-enforceability, and show how the sufficient condition can be used to derive a strategy for the defensive function to enforce concealability.

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Key Insights Distilled From

Event Concealment and Concealability Enforcement in Discrete Event Systems Under Partial Observation

by Wei Duan,Chr... at arxiv.org 04-02-2024

https://arxiv.org/pdf/2205.03170.pdf

Deeper Inquiries

How can the proposed defensive function be extended to handle multiple types of secret events

To extend the proposed defensive function to handle multiple types of secret events, we can introduce a more complex mapping mechanism that associates each type of secret event with specific defensive actions. This can be achieved by defining separate sets of defensive actions for each type of secret event and ensuring that the defensive function can appropriately respond to the occurrence of different types of secret events. By expanding the defensive function to accommodate multiple types of secret events, we can enhance the system's ability to conceal a broader range of confidential information and improve overall security measures.

What are the potential limitations or drawbacks of the defensive function approach compared to other opacity enforcement techniques

While the defensive function approach offers a practical way to enforce concealability in discrete event systems, there are some potential limitations and drawbacks compared to other opacity enforcement techniques. One limitation is the complexity of defining and implementing the defensive function, especially when dealing with multiple types of secret events or complex system behaviors. Additionally, the defensive function may introduce overhead in terms of computational resources and processing time, which could impact system performance. Another drawback is the reliance on predefined defensive actions, which may not always cover all possible scenarios or adapt to dynamic changes in the system. Furthermore, the defensive function approach may require continuous monitoring and updates to ensure its effectiveness, adding maintenance overhead.

How can the concepts of event concealment and concealability enforcement be applied to other types of cyber-physical systems beyond discrete event systems

The concepts of event concealment and concealability enforcement can be applied to various types of cyber-physical systems beyond discrete event systems. For example, in real-time systems, such as industrial control systems or autonomous vehicles, ensuring the concealment of critical events or data from unauthorized entities is crucial for maintaining system security and integrity. By incorporating the principles of event concealment and concealability enforcement, these systems can prevent sensitive information from being exposed to potential threats or malicious actors. Additionally, in networked systems and IoT devices, the concepts of event concealment can be utilized to protect data privacy and prevent unauthorized access to sensitive information. By implementing robust concealability enforcement mechanisms, these systems can enhance their resilience against cyber attacks and unauthorized intrusions.