Analyse formelle des protocoles cryptographiques et flux d'information admissible

Requis des protocoles cyptographiques et méthodes formelles -- L'interférence admissible -- Validation des propriétés de sécurité -- Un modèle de calcul probabiliste polynomial -- Sémantique contextuelle du modèle prospa

A Time-Triggered Constraint-Based Calculus for Avionic Systems

The Integrated Modular Avionics (IMA) architec- ture and the Time-Triggered Ethernet (TTEthernet) network have emerged as the key components of a typical architecture model for recent civil aircrafts. We propose a real-time constraint-based calculus targeted at the analysis of such concepts of avionic embedded systems. We show our framework at work on the modelisation of both the (IMA) architecture and the TTEthernet network, illustrating their behavior by the well-known Flight Management System (FMS)

Probable innocence in the presence of independent knowledge

We analyse the Crowds anonymity protocol under the novel assumption that the attacker has independent knowledge on behavioural patterns of individual users. Under such conditions we study, reformulate and extend Reiter and Rubin's notion of probable innocence, and provide a new formalisation for it based on the concept of protocol vulnerability. Accordingly, we establish new formal relationships between protocol parameters and attackers' knowledge expressing necessary and sufficient conditions to ensure probable innocence

Behavioural equivalences and interference metrics for mobile ad-hoc networks

Abstract Connectivity and communication interference are two key aspects in mobile ad-hoc networks (MANETs). This paper proposes a process algebraic model targeted at the analysis of both such aspects. The framework includes a probabilistic process calculus and a suite of analytical techniques based on a probabilistic observational congruence and an interference-sensitive preorder. The former enables the verification of behavioural equivalences; the latter makes it possible to evaluate the interference level of behaviourally equivalent networks. The result is a comprehensive and effective framework for the behavioural analysis and a quantitative assessment of interference for wireless networks in the presence of node mobility. We show our techniques at work on two realistic case studies

Reconciling Belief and Vulnerability in Information Flow

Belief and vulnerability have been proposed re- cently to quantify information flow in security systems. Both concepts stand as alternatives to the traditional approaches founded on Shannon entropy and mutual information, which were shown to provide inadequate security guarantees. In this paper we unify the two concepts in one model so as to cope with (potentially inaccurate) attackers’ extra knowledge. To this end we propose a new metric based on vulnerability that takes into account the adversary’s beliefs

A Game-Theoretic Analysis of Cooperation in Anonymity Networks

Anonymity systems are of paramount and growing importance in communication networks. They rely on users to cooperate to the realisation of an effective anonymity service. Yet, existing systems are marred by the action of ‘selfish’ free-loaders, so that several cooperation incentives are being proposed. We propose a game-theoretic model of incentives in anonymity networks based on parametric utility functions, which make it flexible, adaptable and realistic.We then use the framework to analyse the cost of cooperation and the performance of the gold-star incentive scheme in the Crowds protocol