Checking Opacity of Vulnerable Critical Systems On-The-Fly

Abstract

Opacity is a security property capturing a system's ability to keep a subset of its behavior hidden from passive, but knowledgeable, observers. In this paper we use the formal definitions of opacity in three of its forms (simple opacity, -step weak opacity and -step strong opacity), basing on finite Labeled Transition Systems as a model. Then we present efficient algorithms for verifying opacity in all these forms within the context of a hybrid, on-the-fly approach. This approach is based on the construction of a Symbolic Observation Graph (SOG) that allows not only the abstraction of the systems behavior but also the preservation of the structure necessary for conducting opacity checking. Our preliminary experimental results are promising and demonstrate effectiveness facing the state-explosion problem which represents the main drawback of existing model checking techniques.

Checking and Enforcing Security Through Opacity in Healthcare Applications

“…The SOG allows the on-the-fly-verification of opacity variants: simple, K-step weak and K-step strong opacity [2]. It also allows the detection of cases of opacity violation.…”

“…if (a ⊆ S) then The verification is performed on LTS-modeled systems. Taking into account that we are trying to opacify Petri nets, the first modification needed to the algorithm presented in [2] consists in replacing the input by a Petri net-modeled system. The petri net has 2 sets of transitions: observable and unobservable actions, and a set of secret marking subsequently representing the states judged to be secret in the LTS.…”

“…The use of SOG-based algorithm in the verification of simple opacity proved efficient [2]. This is due to the symbolic representation of the aggregates (employing BDDs), and to the on-the-fly verification (Opacity is verified while constructing the SOG).…”

“…In this paper, we wish to bridge the gap between the theory of opacity and its practical application through the synthesis of an opaque IoT-based heart attack detection system. Building on the SOG-based verification approach developed in [2], the purpose is to verify opacity in three of its forms (simple, K-step weak opacity and K-step strong opacity) to detect security violations in our synthesized system. Then to contribute an algorithmic approach that enforces simple opacity by padding the system with minimal dummy behavior.…”

Deadline Verification for Web Services Using Timed Automata

“…In these systems, most of the communication is ensured via web services that offer quasiunlimited resources and computational power. However, companies face new challenges concerning security [1][2][3][4] and timing constraints [9][10][11]19]. A web service is a software system designed to support interoperable machine-to-machine interaction over a network [6].…”