Abstract.One of the key demands of cyberphysical systems is that they meet their safety goals. Timed automata has established itself as a formalism for modeling and analyzing the real-time safety aspects of cyberphysical systems. Increasingly it is also demanded that cyberphysical systems meet a number of security goals for confidentiality and integrity. Notions of security based on Information flow control, such as non-interference, provide strong guarantees that no information is leaked; however, many cyberphysical systems leak intentionally some information in order to achieve their purposes.In this paper, we develop a formal approach of information flow for timed automata that allows intentional information leaks. The security of a timed automaton is then defined using a bisimulation relation that takes account of the non-determinism and the clocks of timed automata. Finally, we define an algorithm that traverses a timed automaton and imposes information flow constraints on it and we prove that our algorithm is sound with respect to our security notion.
Timing-based side-channel attacks have matured from an academic exercise to a powerful attack vector in the hand of real-world adversaries. A widely deployed countermeausure against such attacks is to reduce the accuracy of the clocks that are available to adversaries. While a number of high-profile attacks show that this mitigation can be side-stepped, there has not been a principled analysis of the degree of security it provides until now.In this paper, we perform the first information-flow analysis with respect to adversaries with coarse-grained clocks. To this end, we define an adversary model that is parametric in the granularity of the clock and connect it with a system model based on timed automata. We present algorithms for translating such a system to an information-theoretic channel, which enables us to analyze the leakage using standard techniques from quantitative information-flow analysis.We use our techniques to derive insights about the effect of reducing clock resolution on security. In particular, (1) we show that a coarse-grained clock might leak more than a fine-grained one, (2) we give a sufficient condition for when increasing the grain of the clock we achieve better security, and (3) we show that the attack techniques used in the literature form a strict hierarchy in terms of the information an adversary can extract using them.Finally, we illustrate the expressiveness of our development on a case study of a system that uses RSA signatures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.