Hyperproperties relate multiple executions of a program and are commonly used to specify security and information-flow policies. Most existing work has focused on the verification of $k$-safety properties, i.e., properties that state that all $k$-tuples of execution traces satisfy a given property. In this paper, we study the automated verification of richer properties that combine universal and existential quantification over executions. Concretely, we consider $\forall^k\exists^l$ properties, which state that for all $k$ executions, there exist $l$ executions that, together, satisfy a property. This captures important non-$k$-safety requirements, including hyperliveness properties such as generalized non-interference, opacity, refinement, and robustness. We design an automated constraint-based algorithm for the verification of $\forall^k\exists^l$ properties. Our algorithm leverages a sound-and-complete program logic and a (parameterized) strongest postcondition computation. We implement our algorithm in a tool called ForEx and report on encouraging experimental results.
HyperLTL is an extension of linear-time temporal logic for the specification of hyperproperties, i.e., temporal properties that relate multiple computation traces. HyperLTL can express information flow policies as well as properties like symmetry in mutual exclusion algorithms or Hamming distances in error-resistant transmission protocols. Previous work on HyperLTL model checking has focussed on the alternation-free fragment of HyperLTL, where verification reduces to checking a standard trace property over an appropriate self-composition of the system. The alternation-free fragment does, howev…
Reactive programs combine traditional sequential programming constructs with primitives to allow communication with other concurrent agents. They are ubiquitous in modern applications, ranging from components systems and web services, to cyber-physical systems and autonomous robots. In this paper, we present an algebraic verification strategy for concurrent reactive programs, with a large or infinite state space. We define novel operators to characterise interactions and state updates, and an associated equational theory. With this we can calculate a reactive program's denotational semantics, …
These proceedings contain the papers presented at the 11th International Workshop on Automated Specification and Verification of Web Systems (WWV 2015), which was held on 23 June 2015 in Oslo, Norway, as a satellite workshop of the 20th International Symposium on Formal Methods (FM 2015). WWV is a yearly interdisciplinary forum for researchers originating from the following areas: declarative, rule-based programming, formal methods, software engineering and web-based systems. The workshop fosters the cross-fertilisation and advancement of hybrid methods from such areas.
These proceedings contain the papers presented at the 10th International Workshop on Automated Specification and Verification of Web Systems (WWV 2014), which was held on 18 July 2014 in Vienna, Austria, as a satellite workshop of the Federated Logic Conference (FLoC 2014), associated to the 7th International Joint Conference on Automated Reasoning (IJCAR 2014), as part of the Vienna Summer of Logic (VSL 2014). WWV is a yearly workshop that aims at providing an interdisciplinary forum to facilitate the cross-fertilization and the advancement of hybrid methods that exploit concepts and tools dr…
In this report, we present the preliminary work developed for our research project for the APDC (Área Prática de Desenvolvimento Curricular) course. The main goal of this project is to develop a framework, on top of the Why3 tool, for the verification of effectful higher-order programs. We use defunctionalization as an intermediate transformation from higher-order OCaml implementations into first order ones. The target for our translation is WhyML, the Why3's programming language. We believe defunctionalization can be an interesting route for the automated verification of higher-order programs…
Ladder Logics is a programming language standardized in IEC 61131-3 and widely used for programming industrial Programmable Logic Controllers (PLC). A PLC program consists of inputs (whose values are given at runtime by factory sensors), outputs (whose values are given at runtime to factory actuators), and the logical expressions computing output values from input values. Due to the graphical form of Ladder programs, and the amount of inputs and outputs in typical industrial programs, debugging such programs is time-consuming and error-prone. We present, in this paper, a Why3-based tool protot…
Algebraic effects and handlers are a powerful abstraction to build non-local control-flow mechanisms such as resumable exceptions, lightweight threads, co-routines, generators, and asynchronous I/O. All of such features have very evolved semantics, hence they pose very interesting challenges to deductive verification techniques. In fact, there are very few proposed techniques to deductively verify programs featuring these constructs, even fewer when it comes to automated proofs. In this paper, we present an extension to Cameleer, a deductive verification tool for OCaml code, that allows one to…
With declining costs and increasing performance, the deployment of renewable energy systems is growing faster. Particular attention is given to stand-alone solar photovoltaic systems in rural areas or where grid extension is unfeasible. Tools to evaluate electrification projects are available, but they are based on simulations that do not cover all aspects of the design space. Automated verification using model checking has proven to be an effective technique to program verification. This paper marks the first application of software model checking to formally verify the design of a stand-alon…
A large number of web applications is based on a relational database together with a program, typically a script, that enables the user to interact with the database through embedded SQL queries and commands. In this paper, we introduce a method for formal automated verification of such systems which connects database theory to mainstream program analysis. We identify a fragment of SQL which captures the behavior of the queries in our case studies, is algorithmically decidable, and facilitates the construction of weakest preconditions. Thus, we can integrate the analysis of SQL queries into a …
We present symQV, a symbolic execution framework for writing and verifying quantum computations in the quantum circuit model. symQV can automatically verify that a quantum program complies with a first-order specification. We formally introduce a symbolic quantum program model. This allows to encode the verification problem in an SMT formula, which can then be checked with a delta-complete decision procedure. We also propose an abstraction technique to speed up the verification process. Experimental results show that the abstraction improves symQV's scalability by an order of magnitude to quan…
This paper surveys how formal verification can be used to prove the correctness of ad hoc routing protocols, which are fundamental infrastructure of wireless sensor networks. The existing techniques fall into two classes: verification on small-scale networks and verification on unbounded networks. The former one is always fully automatic and easy to use, thanks to the limited state space generated in verification. However, it cannot prove the correctness over all cases. The latter one can provide a complete proof based on abstractions of unbounded network. However, it usually needs user interv…
Timed Intruder Models have been proposed for the verification of Cyber-Physical Security Protocols (CPSP) amending the traditional Dolev-Yao intruder to obey the physical restrictions of the environment. Since to learn a message, a Timed Intruder needs to wait for a message to arrive, mounting an attack may depend on where Timed Intruders are. It may well be the case that in the presence of a great number of intruders there is no attack, but there is an attack in the presence of a small number of well placed intruders. Therefore, a major challenge for the automated verification of CPSP is to d…
The growing complexity and diversity of models used in the engineering of dependable systems implies that a variety of formal methods, across differing abstractions, paradigms, and presentations, must be integrated. Such an integration relies on unified semantic foundations for the various notations, and co-ordination of a variety of automated verification tools. The contribution of this paper is Isabelle/UTP, an implementation of Hoare and He's Unifying Theories of Programming, a framework for unification of formal semantics. Isabelle/UTP permits the mechanisation of computational theories fo…
Freie Universität Berlin（柏林自由大学）；Cambridge University（剑桥大学）
We present an automated verification of the well-known modal logic cube in Isabelle/HOL, in which we prove the inclusion relations between the cube's logics using automated reasoning tools. Prior work addresses this problem but without restriction to the modal logic cube, and using encodings in first-order logic in combination with first-order automated theorem provers. In contrast, our solution is more elegant, transparent and effective. It employs an embedding of quantified modal logic in classical higher-order logic. Automated reasoning tools, such as Sledgehammer with LEO-II, Satallax and …
These proceedings include selected papers presented at the 9th Workshop on Horn Clauses for Verification and Synthesis and the Tenth International Workshop on Verification and Program Transformation, both affiliated with ETAPS 2022. Many Program Verification and Synthesis problems of interest can be modeled directly using Horn clauses and many recent advances in the CLP and CAV communities have centered around efficiently solving problems presented as Horn clauses. The HCVS series of workshops aims to bring together researchers working in the communities of Constraint/Logic Programming (e.g., …
In industrial model-based development (MBD) frameworks, requirements are typically specified informally using textual descriptions. To enable the application of formal methods, these specifications need to be formalized in the input languages of all formal tools that should be applied to analyse the models at different development levels. In this paper we propose a unified approach for the computer-assisted formal specification of requirements and their fully automated translation into the specification languages of different verification tools. We consider a two-stage MBD scenario where first…
State-machine based notations are ubiquitous in the description of component systems, particularly in the robotic domain. To ensure these systems are safe and predictable, formal verification techniques are important, and can be cost-effective if they are both automated and scalable. In this paper, we present a verification approach for a diagrammatic state machine language that utilises theorem proving and a denotational semantics based on Unifying Theories of Programming (UTP). We provide the necessary theory to underpin state machines (including induction theorems for iterative processes), …
Formal Verification of Safety Architectures for Automated Driving
National Institute of Informatics（国立信息学研究所）；National Institute of Advanced Industrial Science and Technology (AIST)（国立先进工业科学技术研究院（AIST））；Japanese-French Laboratory for Informatics（日法信息学实验室）；The Graduate University for Advanced Studies (SOKENDAI)（综合研究大学院大学（SOKENDAI））
Scalable and automatic formal verification for concurrent systems is always demanding. In this paper, we propose a verification framework to support automated compositional reasoning for concurrent programs with shared variables. Our framework models concurrent programs as succinct automata and supports the verification of multiple important properties. Safety verification and simulations of succinct automata are parallel compositional, and safety properties of succinct automata are preserved under refinements. We generate succinct automata from infinite state concurrent programs in an automat…
Stochastic hybrid systems have received significant attentions as a relevant modelling framework describing many systems, from engineering to the life sciences: they enable the study of numerous applications, including transportation networks, biological systems and chemical reaction networks, smart energy and power grids, and beyond. Automated verification and policy synthesis for stochastic hybrid systems can be inherently challenging: this is due to the heterogeneity of their dynamics (presence of continuous and discrete components), the presence of uncertainty, and in some applications the…
The output of an automated theorem prover is usually presented by using a text format, they are often too heavy to be understood. In model checking setting, it would be helpful if one can observe the structure of models and the verification procedures. A 3D visualization tool (\textsf{VMDV}) is proposed in this paper to address these problems. The facility of \vmdv is illustrated by applying it to a proof systems.
Automated Experiment Design for Data-Efficient Verification of Parametric Markov Decision Processes
Department of Computer Science, University of Oxford（牛津大学计算机科学系）；Department of Electrical Engineering, Eindhoven University of Technology（埃因霍温理工大学电气工程系）
We introduce a framework for the formal specification and verification of quantum circuits based on the Feynman path integral. Our formalism, built around exponential sums of polynomial functions, provides a structured and natural way of specifying quantum operations, particularly for quantum implementations of classical functions. Verification of circuits over all levels of the Clifford hierarchy with respect to either a specification or reference circuit is enabled by a novel rewrite system for exponential sums with free variables. Our algorithm is further shown to give a polynomial-time dec…
In this paper, we propose a tool, called DataProVe, for specifying high-level data protection policies and system architectures, as well as verifying the conformance between them in a fully automated way. The syntax of the policies and the architectures is based on semi-formal languages, and the automated verification engine relies on logic and resolution based proofs. The functionality and operation of the tool are presented using different examples.
