Transforming Opacity Verification to Nonblocking Verification in Modular Systems

Mohajerani, Sahar; Lafortune, Stéphane

doi:10.1109/tac.2019.2934708

Cited by 24 publications

(9 citation statements)

References 22 publications

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“…Notice that x ∈ X \ S because x i ∈ X i \ S[i]. Therefore, the lemma holds by ( 12), (13), and Definition 3. Remark 3: Assumption 1 is a necessary condition for Theorem 3.…”

Section: Local Initial-state Opacitymentioning

confidence: 91%

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Local Opacity Verification for Distributed Discrete Event Systems

Pruekprasert¹,

Cai²

2021

Preprint

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This paper studies current-state opacity and initial-state opacity verification of distributed discrete event systems. The distributed system's global model is the parallel composition of multiple local systems: each of which represents a component. We propose sufficient conditions for verifying opacity of the global system model based only on the opacity of the local systems. We also present efficient approaches for the opacity verification problem that only rely on the intruder's observer automata of the local DESs.

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“…Notice that x ∈ X \ S because x i ∈ X i \ S[i]. Therefore, the lemma holds by ( 12), (13), and Definition 3. Remark 3: Assumption 1 is a necessary condition for Theorem 3.…”

Section: Local Initial-state Opacitymentioning

confidence: 91%

“…These data structures can be large, especially for distributed DESs with several local components. To mitigate this problem, many previous studies (e.g., [11], [12], [13]) investigated compositional opacity verification approaches. The approaches construct abstract structures of local DESs.…”

Section: Introductionmentioning

confidence: 99%

Local Opacity Verification for Distributed Discrete Event Systems

Pruekprasert¹,

Cai²

2021

Preprint

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“…In the following discussion, a restricted version of observation equivalence called opaque observation equivalence is employed. This notion was first defined in [27] in the context of verifying opacity.…”

Section: A Opaque Observation Equivalencementioning

confidence: 99%

Compositional and Abstraction-Based Approach for Synthesis of Edit Functions for Opacity Enforcement

Mohajerani

Lafortune

2020

IEEE Trans. Automat. Contr.

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This paper develops a novel compositional and abstraction-based approach to synthesize edit functions for opacity enforcement in modular discrete event systems. Edit functions alter the output of the system by erasing or inserting events in order to obfuscate the outside intruder, whose goal is to infer the secrets of the system from its observation. We synthesize edit functions to solve the opacity enforcement problem in a modular setting, which significantly reduces the computational complexity compared with the monolithic approach. Two abstraction methods called opaque observation equivalence and opaque bisimulation are first employed to abstract the individual components of the modular system and their observers. Subsequently, we propose a method to transform the synthesis of edit functions to the calculation of modular supremal nonblocking supervisors. We show that the edit functions synthesized in this manner correctly solve the opacity enforcement problem.

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“…The reason for evaluating this abstraction is that it is known to be more efficient than visible bisimulation. This abstraction has independently been proposed for opacity verification by Mohajerani and Lafortune (2019) and . In both reports, the abstraction gives an enormous reduction in computation time, compared to opacity verification without abstraction.…”

Section: Modularity and Abstractionmentioning

confidence: 99%

Incremental Observer Reduction Applied to Opacity Verification and Synthesis

Noori-Hosseini¹,

Lennartson²,

Hadjicostis³

2018

Preprint

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An incremental observer generation for modular systems is presented in this paper. It is applied to verification and enforcement of current-state opacity and current-state anonymity, both of which are security/privacy notions that have attracted attention recently. The complexity due to synchronization of subsystems, but also the exponential observer generation complexity, are tackled by local observer generation and an incremental abstraction. Observable events are hidden and abstracted step by step when they become local after synchronization with other subsystems. For systems with shared unobservable events, complete observers can not be generated before some local models are synchronized. At the same time, observable events should be abstracted when they become local, to avoid state space explosion. Therefore, a new combined incremental abstraction and observer generation is proposed. This requires some precaution (detailed in the paper) to be able to accomplish local abstractions before shared unobservable events are removed by observer generation. Furthermore, it is shown how current state opacity and anonymity can be enforced by a supervisor. This is achieved by a natural extension of the verification problem to a supervisory control problem based on forbidden states and incremental abstraction. Finally, a modular and scalable building security problem with arbitrary number of This work was partly carried out within the project SyTec -Systematic Testing of Cyber-Physical Systems, a Swedish Science Foundation grant for strong research environment. The support is gratefully acknowledged.

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Transforming Opacity Verification to Nonblocking Verification in Modular Systems

Cited by 24 publications

References 22 publications

Local Opacity Verification for Distributed Discrete Event Systems

Local Opacity Verification for Distributed Discrete Event Systems

Compositional and Abstraction-Based Approach for Synthesis of Edit Functions for Opacity Enforcement

Incremental Observer Reduction Applied to Opacity Verification and Synthesis

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