Communications multi-niveaux sécurisées dans une flotte de terminaux mobiles

Current mobile devices, and mobile phones in particular, are equipped with different wireless technologies that increase and diversify their communication capabilities. The combined and effective use of these technologies offers various opportunities in terms of services and applications. However, it requires detailed analysis in terms of security and choice of the communication mean to use according to context-dependent criteria : energy costs, financial costs, preferences of the involved entities, privacy issues, etc. This problem has emerged as a key issue in the Smart Urban Spaces project in which this thesis was carried out. Our contribution to this project is the creation of collaborative applications adequately using the available wireless technologies on the considered equipments. In other words, we try to use the most appropriate communication mean (according to the criteria listed above) that two or more mobile devices can use to perform exchanges (without considering their respective positions). Then, the transparency of targets localization becomes a rule. We can synthesize the central question that we have chosen to study in the following manner : how to allow a set of mobile terminals (mobile phones in particular) to securely communicate using the most appropriate technology depending on the context ? Our goal is to answer this question by defining a multilevel platform taking into account the different technologies available on the considered equipments. It is necessaty to identify the elements to consider in the design of the platform, to model them, to develop reference applications and to validate the relevance of the proposed solutions with qualitative and quantitative evaluations.