Investigating Optimal Progress Measures for Verification of the WebSocket Protocol

The sweep-line method is a state space reduction technique formemory-efficient on-the-fly verification of concurrent systems. Themethod relies on a progress measure capturing inherent progress in thesystem under verification to store only fragments of the state space inmemory at a time and thereby reduce peak memory usage. The sweep-line method has been applied to many concurrent systems, but theoptimality of progress measures in terms of the peak number of statesstored has not been investigated. Assessing the optimality of a progressmeasure is important since memory in most cases is the limiting factorin verification using state spaces. We derive lower bounds for the peaknumber states and present initial experimental results on near optimalprogress measures for verification of the IETF WebSocket protocol

Seventh Workshop and Tutorial on Practical Use of Coloured Petri Nets and the CPN Tools, Aarhus, Denmark, October 24-26, 2006

This booklet contains the proceedings of the Seventh Workshop on Practical Use of Coloured Petri Nets and the CPN Tools, October 24-26, 2006. The workshop is organised by the CPN group at the Department of Computer Science, University of Aarhus, Denmark. The papers are also available in electronic form via the web pages: http://www.daimi.au.dk/CPnets/workshop0

Automated Validation of State-Based Client-Centric Isolation with TLA ⁺

Clear consistency guarantees on data are paramount for the design and implementation of distributed systems. When implementing distributed applications, developers require approaches to verify the data consistency guarantees of an implementation choice. Crooks et al. define a state-based and client-centric model of database isolation. This paper formalizes this state-based model in, reproduces their examples and shows how to model check runtime traces and algorithms with this formalization. The formalized model in enables semi-automatic model checking for different implementation alternatives for transactional operations and allows checking of conformance to isolation levels. We reproduce examples of the original paper and confirm the isolation guarantees of the combination of the well-known 2-phase locking and 2-phase commit algorithms. Using model checking this formalization can also help finding bugs in incorrect specifications. This improves feasibility of automated checking of isolation guarantees in synthesized synchronization implementations and it provides an environment for experimenting with new designs.</p

Animation-based validation of reactive software systems using behavioural models

Tese de doutoramento em InformáticaDuring the development of software systems, validation is a crucial activity to guarantee that the software system ful lls the users' needs and expectations. A key issue to have a successful validation consists in adopting a process where users and clients can actively discuss the requirements of the system under development. A reactive system is expected to continuously interact with its environment. Usually, the interaction of a reactive system with its environment is supported by a set of nonterminating processes that operate in parallel. During the interaction, the reactive system must answer to high-priority events, even when the system is executing something else. Due to above characteristics, the behaviour of reactive systems can be very complex. The approach suggested in this thesis assumes that the requirements of reactive software systems are partially described by use case diagrams, and each use case is detailed by a collection of scenario descriptions. Within this approach, one can obtain, from a set of behavioural scenarios of a given system, an executable behavioural model that can support, when complemented with animation- and domain-speci c elements, a graphical animation for reproducing that set of scenarios for validation purposes. Animating the scenarios using graphical elements from the application domain ensures an e ective involvement of the users in the system's validation. The Coloured Petri nets (CPNs) modelling language is used as the notation to obtain the behavioural models, due to its natural support for mechanisms like concurrency, synchronisation, and resource sharing and its tool support. The obtained CPN model is guaranteed to be (1) parametric, allowing an easy modi cation of the initial conditions of the scenarios, (2) environment-descriptive, meaning that it includes the state of the relevant elements of the environment, and (3) animation-separated, implying that the elements related to the animation are separated from the other ones. We validate our approach based on its application to three case studies of reactive systems.Durante o desenvolvimento de sistemas de software, a validação é uma actividade crucial para garantir que o sistema de software satisfaz as necessidades e expectativas do utilizador. O sucesso na validação consiste na utilização de um processo onde os utilizadores e os clientes possam discutir de uma forma activa os requisitos do sistema que está a ser desenvolvido. Um sistema reactivo está continuamente em interacção com o seu ambiente, que é geralmente suportada por um conjunto de processos intermináveis que operam em paralelo. Durante a interacção, o sistema reactivo dever a responder aos eventos com alta prioridade, mesmo quando o sistema está a executar algo diferente. Devido às características anteriores, o comportamento dos sistemas reactivos pode ser muito complexo. A abordagem sugerida nesta tese assume que os requisitos de sistemas reactivos são em parte descritos por diagramas de casos de uso e que cada caso de uso é detalhado por uma colecção de descrições de cenários. Nesta abordagem, é possível obter, a partir de um conjunto de cenários de um dado sistema, um modelo comportamental que seja executável e que suporte, quando complementado com elementos específicos, uma animação gráfica que reproduza aquele conjunto de cenários para fins de validação. A animação dos cenários utilizando elementos gráficos do domínio da aplicação garante um envolvimento efectivo dos utilizadores na validação do sistema. A linguagem de modelação redes de Petri coloridas (CPNs) é usada como a notação para obter os modelos comportamentais, devido ao seu suporte natural a mecanismos como a concorrência, sincronização e partilha de recursos, e às suas ferramentas de suporte. Se as recomendações da abordagem proposta foram seguidas, temos a garantia que o modelo CPN: (1) parametriza as condições iniciais dos cenários, (2) contém uma descrição do ambiente, incluindo o estado dos seus elementos, e (3) separa os elementos relacionados com a animação dos outros elementos do modelo. A validação da nossa abordagem tem por base a sua aplicação a três casos de estudo de sistemas reactivos.Fundação para a Ciência e a Tecnologia (FCT) SFRH/BD/19718/200

Proceedings of the 3rd International Workshop on Formal Aspects in Security and Trust (FAST2005)

The present report contains the pre-proceedings of the third international Workshop on Formal Aspects in Security and Trust (FAST2005), held in Newcastle upon Tyne, 18-19 July 2005. FAST is an event affliated with the Formal Methods 2005 Congress (FM05). The third international Workshop on Formal Aspects in Security and Trust (FAST2005) aims at continuing the successful effort of the previous two FAST workshop editions for fostering the cooperation among researchers in the areas of security and trust. The new challenges offered by the so-called ambient intelligence space, as a future paradigm in the information society, demand for a coherent and rigorous framework of concepts, tools and methodologies to provide user\u27s trust&confidence on the underlying communication/interaction infrastructure. It is necessary to address issues relating to both guaranteeing security of the infrastructure and the perception of the infrastructure being secure. In addition, user confidence on what is happening must be enhanced by developing trust models effective but also easily comprehensible and manageable by users

Formal Aspects in Security and Trust

his book constitutes the thoroughly refereed post-proceedings of the Third International Workshop on Formal Aspects in Security and Trust, FAST 2005, held in Newcastle upon Tyne, UK in July 2005. The 17 revised papers presented together with the extended abstract of 1 invited paper were carefully reviewed and selected from 37 submissions. The papers focus on formal aspects in security and trust policy models, security protocol design and analysis, formal models of trust and reputation, logics for security and trust, distributed trust management systems, trust-based reasoning, digital assets protection, data protection, privacy and ID issues, information flow analysis, language-based security, security and trust aspects in ubiquitous computing, validation/analysis tools, web service security/trust/privacy, GRID security, security risk assessment, and case studies

Actes des Sixièmes journées nationales du Groupement De Recherche CNRS du Génie de la Programmation et du Logiciel

National audienceCe document contient les actes des Sixièmes journées nationales du Groupement De Recherche CNRS du Génie de la Programmation et du Logiciel (GDR GPL) s'étant déroulées au CNAM à Paris du 11 au 13 juin 2014. Les contributions présentées dans ce document ont été sélectionnées par les différents groupes de travail du GDR. Il s'agit de résumés, de nouvelles versions, de posters et de démonstrations qui correspondent à des travaux qui ont déjà été validés par les comités de programmes d'autres conférences et revues et dont les droits appartiennent exclusivement à leurs auteurs