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Privacy-preserving in mobile business supplying location-based services (LBS) has the potential to become a primary concern for clients and service providers. In m-business providing LBS services, a client sends its exact locations to service providers. This data may involve sensitive and private personal information. Therefore, the misuse of location information by service providers creates privacy issues for clients. Moreover, the query must not be linked to the mobile client, even if the location information is exposed willingly by her/him to obtain specific services. Thus, there are location cloaking algorithms that allow the protection of the location privacy of mobile users. Hence, many temporal and spatial approaches to cloaking a specific user's location have been proposed. Different from the existing methods, the current works define location and query privacy separately. Therefore, in this paper, we investigate the issues related to the mobile client privacy. Mainly, we aim to preserve the client location privacy as well as the continuous queries privacy, where mobile clients continuously emit different queries during their travels. It's on this premise that we propose a new clique-based cloaking algorithm named Mobile Clique Cloak (MCC) to preserve the mobile client's privacy in the M-business providing LBS services. Also, to build the cloaking region in our approach, we take into account the similarity of client velocity and direction to obtain a right balance between quality of service QoS and privacy. Furthermore, we generate different realistic dummies instead of dropping the query; thus, all queries will be processed even in the case of k−1 other mobile clients' queries cannot be found. Moreover, our work deals with a series of attacks in the same cloaking process (location attack, tracking attack, query sampling attacks and homogenous attack). We evaluate our approach from three aspects: privacy guaranty, quality of service and performance. Experimental evaluation of our algorithms on a real world map shows that our approach ensures total privacy for clients and protects the privacy of clients during the entire query period whiles allowing clients' choice of privacy requirements. Besides, we compare our algorithm with existing privacy protection algorithms such as V-DCA, D-TC and GCA. According to the evaluation results and a comparison of the algorithms, our algorithm MCC can make a good balance between quality of service, performance and privacy. [ABSTRACT FROM AUTHOR]

Role-Based Access Control (RBAC) is one of the most used models in designing and implementation of security policies, in large networking systems. Basic RBAC model does not consider temporal aspects which are so important in such policies. Temporal RBAC (TRBAC) is proposed to deal with these temporal aspects. Despite the elegance of these models, designing a security policy remains a challenge. Designers must ensure the consistency and the correctness of the policy. The use of formal methods provides techniques for proving that the designed policy is consistent. In this paper, we present a formal modelling/analysis approach of TRBAC policies. This approach uses Hierarchical Timed Coloured Petri Nets (HTCPN) formalism to model the TRBAC policy, and the CPN-tool to analyse the generated models. The timed aspect, in HTCPN, facilitates the consideration of temporal constraints introduced in TRBAC. The hierarchical aspect of HTCPN makes the model "manageable", in spite of the complexity of TRBAC policy specification. The analysis phase allows the verification of many important properties about the TRBAC security policy. [ABSTRACT FROM AUTHOR]

In the original publication of this article, the third author's name was incorrectly published. [ABSTRACT FROM AUTHOR]

Nowadays, a wide range of systems are becoming structurally dynamic, variably interconnected, and highly complex. The use of classical formal approaches, such as Petri nets, in the design of such systems becomes neither convenient nor sufficient. Indeed, they cannot handle, in a natural way, the dynamic structure and the growing complexity of modern systems. Introducing reconfigurability in Petri nets, as well as generalized stochastic Petri nets increases the modeling power, but decreases the applicability of analysis techniques. In fact, several properties become undecidable In this paper, we extend generalized stochastic Petri nets to a reconfigurable formalism, while maintaining verifiability with reduced complexity. The proposed approach identifies a set of properties that are preserved after reconfiguration. These properties are decidable with reduced time and space complexity. The use of the proposed formalism is illustrated through a running example. • A new Petri nets based formalism is proposed for reconfigurable systems. • The new formalism handles two aspects: stochastic time and reconfigurability. • Improved Net Rewriting Systems and Generalized Stochastic Petri Nets are combined. • A new approach for the performance evaluation is proposed and exploited. • The formalism is exploited in an Reconfigurable Manufacturing Systems case study. [ABSTRACT FROM AUTHOR]