Overview of Opacity in Discrete Event Systems

Ye, Guo; Jiang, Xiaoning; Guo, Chaozhong; Wang, Shouguang; Karoui, Oussama

doi:10.1109/access.2020.2977992

Cited by 10 publications

(10 citation statements)

References 96 publications

(139 reference statements)

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“…At M 0 = p 1 + p 2 , the transition t 1 could be firable. The set of explanations of t 1 is Σ(M 0 , t 1 ) = {ε, t 2 , t 2 t 3 } and Y(M 0 , t 1 ) = { 0, [10] T , [11] T }. Since Y(M 0 , t 1 ) ≠ { 0}, there exists at least a transition sequence t 2 t 1 such that λ(t 2 t 1 ) = db ∈ L NS and Pr(db) = Pr(b) = b.…”

Section: Verification Of Language-based Opacitymentioning

confidence: 99%

“…The initial marking of the MBRG is then initialized based on the initial marking M 0 and added to the set MB . After that, M := M \ {M 0 } is done and for all basis markings M ∈ M, if M ∈ M \ M, then a composed pair (M, − 1) is added to the set M. Once M ∉ M \ M, the binary scalar of M is computed according to Equation (10), i.e., α(M), and the pair (M, α(M)) is added to the set . At the end, the set of markings of β is (Steps 15 to 32).…”

Section: Modified Basis Reachability Graph (Mbrg)mentioning

confidence: 99%

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Language-based Opacity Verification and Enforcement in the Framework of Labeled Petri Nets

Habbachi

et al. 2022

Science Progress

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This work deals with the language-based opacity verification and enforcement problems in discrete event systems modeled with labeled Petri nets. Opacity is a security property that relates to privacy protection by hiding secret information of a system from an external observer called an “intruder”. A secret can be a subset of a system's language. In this case, opacity is referred to as language-based opacity. A system is said to be language-based opaque if an intruder, with a partial observation on the system's behavior, cannot deduce whether the sequences of events corresponding to the generated observations are included in the secret language or not. We propose a novel and efficient approach for language-based opacity verification and enforcement, using the concepts of basis markings and basis partition. First, a sufficient condition is formulated to check language-based opacity for labeled Petri nets by solving an integer-programming problem. A unique graph, called a modified basis reachability graph (MBRG), is then derived to verify different language-based opacity properties. The proposed method relaxes the acyclicity assumption of the unobservable transition subnet thanks to the basis partition notion. A new embedded insertion function technique is also provided to deal with opacity enforcement. This technique ensures that no new observed behavior is created. A verification algorithm is developed to check the enforceability of a system. Finally, once a system is proved to be enforceable, an algorithm is given to construct a new structure, called an insertion automaton, which synthesizes all possible insertion functions that ensure opacity.

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Section: Verification Of Language-based Opacitymentioning

confidence: 99%

Section: Modified Basis Reachability Graph (Mbrg)mentioning

confidence: 99%

Language-based Opacity Verification and Enforcement in the Framework of Labeled Petri Nets

Habbachi

et al. 2022

Science Progress

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“…Given a supervisor S A that satisfies Eq. (1) and a homomorphic encryption scheme {KGen, Enc, Dec, Eval}, if there exists a map f ε such that: f ε (Enc(q(k)), Enc(e(k))) = Enc(f (q(k), e(k))), (15) we say that the given S A can be homomorphically encrypted through a specified encryption scheme. We call f ε as an encrypted control policy.…”

Section: A Feasibility Of Applying Homomorphic Encryption Schemementioning

confidence: 99%

“…Passive attacks are those in which an attacker intercepts information flows between two parties to steal information stored in a system by eavesdropping or similar means. Opacity is an information flow property that characterizes the inability for an external intruder to know whether the given "secret" behavior happens in a system [14], [15]. However, almost all studies on opacity are based on data transmitted in plaintext data.…”

Section: Introductionmentioning

confidence: 99%

Homomorphic Encryption of Supervisory Control Systems Using Automata

Zhou

Nasr

et al. 2020

IEEE Access

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Cyber-physical systems have been highly integrated into many contemporary infrastructures. As this integration deepens, the importance of protecting these systems from unauthorized access and data corruption increases. Nowadays, cyber-physical systems are not well protected against network attacks. One solution is to improve the security of a system by encrypting the transmitted data. In this paper, we consider the encryption of supervisors of discrete event systems modeled with deterministic finite-state automata. We propose an encryption framework of supervisory control systems based on the matrix notation of automata. The purpose of using matrix notation is to make it suitable for homomorphic encryption schemes over integers, which are emerging in the cryptography area. We calculate the entropy of the matrix notation and find that as the size of a system increases, it gets smaller and approaches zero. Owing to the low entropy of the matrix notation, we propose an algorithm to enhance its entropy. By applying the entropy-enhancing process, the distribution characteristics of entries in matrices or vectors can be hidden to avoid a brute force attack. Correspondingly, we propose an entropy restoration algorithm to ensure that the control action can be transmitted correctly.

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“…Several notions of opacity have been proposed and studied in the literature [4], [5], [6]. Overviews, surveys on commonly used techniques and existing tools, and historical remarks on the opacity of DES are presented in [7], [8], [9].…”

Section: Introductionmentioning

confidence: 99%

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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Overview of Opacity in Discrete Event Systems

Cited by 10 publications

References 96 publications

Language-based Opacity Verification and Enforcement in the Framework of Labeled Petri Nets

Language-based Opacity Verification and Enforcement in the Framework of Labeled Petri Nets

Homomorphic Encryption of Supervisory Control Systems Using Automata

Local Opacity Verification for Distributed Discrete Event Systems

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