scholarly journals Improving SAT-based Bounded Model Checking for Existential CTL through Path Reuse

10.29007/2s1q ◽  
2018 ◽  
Author(s):  
Chuan Jiang ◽  
Gianfranco Ciardo

A complementary technique to decision-diagram-based model checking is SAT-based bounded model checking (BMC), which reduces the model checking problem to a propositional satisfiability problem so that the corresponding formula is satisfiable iff a counterexample or witness exists. Due to the branching time nature of computation tree logic (CTL), BMC for the universal fragment of CTL (ACTL) considers a counterexample in a bounded model as a set of bounded paths. Since the existential fragment of CTL (ECTL) is dual to ACTL, and ACTL formulas are often negated to obtain ECTL ones in practice, we focus on BMC for ECTL and propose an improved translation that generates a possibly smaller propositional formula by reducing the number of bounded paths to be considered in a witness. Experimental results show that the formulas generated by our approach are often easier for a SAT solver to answer. In addition, we propose a simple modification to the translation so that it is also defined for models with deadlock states.

10.29007/z3g2 ◽  
2019 ◽  
Author(s):  
Thorsten Ehlers ◽  
Dirk Nowotka

In this paper we present new implementation details and benchmarking results for our parallel portfolio solver TopoSAT2. In particular, we discuss ideas and implementation details for the exchange of learned clauses in a massively-parallel SAT solver which is designed to run more that 1, 000 solver threads in parallel. Furthermore, we go back to the roots of portfolio SAT solving, and discuss the impact of diversifying the solver by using different restart- , branching- and clause database management heuristics. We show that these techniques can be used to tune the solver towards different problems. However, in a case study on formulas derived from Bounded Model Checking problems we see the best performance when using a rather simple clause exchange strategy. We show details of these tests and discuss possible explanations for this phenomenon.As computing times on massively-parallel clusters are expensive, we consider it especially interesting to share these kind of experimental results.


2012 ◽  
Vol 23 (7) ◽  
pp. 1656-1668 ◽  
Author(s):  
Cong-Hua ZHOU ◽  
Zhi-Feng LIU ◽  
Chang-Da WANG

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Rui Wang ◽  
Wanwei Liu ◽  
Tun Li ◽  
Xiaoguang Mao ◽  
Ji Wang

As a complementary technique of the BDD-based approach, bounded model checking (BMC) has been successfully applied to LTL symbolic model checking. However, the expressiveness of LTL is rather limited, and some important properties cannot be captured by such logic. In this paper, we present a semantic BMC encoding approach to deal with the mixture ofETLfandETLl. Since such kind of temporal logic involves both finite and looping automata as connectives, all regular properties can be succinctly specified with it. The presented algorithm is integrated into the model checker ENuSMV, and the approach is evaluated via conducting a series of imperial experiments.


Author(s):  
Alexander Koch ◽  
Michael Schrempp ◽  
Michael Kirsten

AbstractCard-based cryptography provides simple and practicable protocols for performing secure multi-party computation with just a deck of cards. For the sake of simplicity, this is often done using cards with only two symbols, e.g., $$\clubsuit $$ ♣ and $$\heartsuit $$ ♡ . Within this paper, we also target the setting where all cards carry distinct symbols, catering for use-cases with commonly available standard decks and a weaker indistinguishability assumption. As of yet, the literature provides for only three protocols and no proofs for non-trivial lower bounds on the number of cards. As such complex proofs (handling very large combinatorial state spaces) tend to be involved and error-prone, we propose using formal verification for finding protocols and proving lower bounds. In this paper, we employ the technique of software bounded model checking (SBMC), which reduces the problem to a bounded state space, which is automatically searched exhaustively using a SAT solver as a backend. Our contribution is threefold: (a) we identify two protocols for converting between different bit encodings with overlapping bases, and then show them to be card-minimal. This completes the picture of tight lower bounds on the number of cards with respect to runtime behavior and shuffle properties of conversion protocols. For computing AND, we show that there is no protocol with finite runtime using four cards with distinguishable symbols and fixed output encoding, and give a four-card protocol with an expected finite runtime using only random cuts. (b) We provide a general translation of proofs for lower bounds to a bounded model checking framework for automatically finding card- and run-minimal (i.e., the protocol has a run of minimal length) protocols and to give additional confidence in lower bounds. We apply this to validate our method and, as an example, confirm our new AND protocol to have its shortest run for protocols using this number of cards. (c) We extend our method to also handle the case of decks on symbols $$\clubsuit $$ ♣ and $$\heartsuit $$ ♡ , where we show run-minimality for two AND protocols from the literature.


2017 ◽  
Vol 2 (20) ◽  
pp. 131-147
Author(s):  
Agnieszka M. Zbrzezny

We compare two SAT-based bounded model checking algorithms for the properties expressed in the existential fragment of a soft real-time computation tree logic (RTECTL) and in the existential fragment of computation tree logic (ECTL). To this end, we use the generic pipeline paradigm (GPP) and the train controller system (TC), the classic concurrency problems, which we formalise by means of a finite transition system. We consider several properties of the problems that can be expressed in both RTECTL and ECTL, and we present the performance evaluation of the mentioned bounded model checking methods by means of the running time and the memory used.


Sign in / Sign up

Export Citation Format

Share Document