Feasible Trace Reconstruction for Rewriting Approximations

Abstract

Abstract. Term Rewriting Systems are now commonly used as a modeling language for programs or systems. On those rewriting based models, reachability analysis, i.e. proving or disproving that a given term is reachable from a set of input terms, provides an efficient verification technique. For disproving reachability (i.e. proving non reachability of a term) on non terminating and non confluent rewriting models, KnuthBendix completion and other usual rewriting techniques do not apply. Using the tree automaton completion technique, it has been shown that the non reachability of a term t can be shown by computing an overapproximation of the set of reachable terms and prove that t is not in the approximation. However, when the term t is in the approximation, nothing can be said. In this paper, we refine this approach and propose a method taking advantage of the approximation to compute a rewriting path to the reachable term when it exists, i.e. produce a counter example. The algorithm has been prototyped in the Timbuk tool. We present some experiments with this prototype showing the interest of such an approach w.r.t. verification of rewriting models.

Ubiquitous Verification of Ubiquitous Systems

“…Additionally, security analyses of such protocols are awkward to make for humans, due to the complexity induced by multiple interleaved protocol runs and the unpredictability of the attacker behavior. Formal methods, and in particular static analysis techniques such as type systems [1,24,14,5,7,9], abstract interpretation [23,12,13,6], and theorem proving [11] proved to constitute salient tools for reliably analyzing security protocols. Nowadays, the analysis of sophisticated properties, such as anonymity, privacy, and access control policies, is within the scope of automated verification tools and the running time for such analyses ranges from a few seconds to a couple of hours, depending on the complexity of the protocol and of the cryptographic primitives.…”

The CASPA Tool: Causality-Based Abstraction for Security Protocol Analysis

“…Related Work We demonstrate the expressiveness and efficiency of our tool by drawing a comparison with T4ASP [13,9], the static analyzer for secrecy properties offered by AVISPA [2], the well-known tool suite for security protocol analysis. CASPA is capable of coping with a substantially larger set of protocols than TA4SP, and it furthermore excels in terms of performance; moreover, CASPA is capable of verifying both secrecy and authenticity properties in contrast to only secrecy properties in the case of TA4SP.…”