Mémoire d ' Habilitation à Diriger les Recherches

Security is a very old concern, which until quite recently was mostly of interest for military purposes. The deployment of electronic commerce changes this drastically. The security of exchanges is ensured by cryptographic protocols which are notoriously error prone. The formal veri cation of cryptographic protocols is a di cult problem that can be seen as a particular model-checking problem in an hostile environment. Many results and tools have been developed to automatically verify cryptographic protocols. Recently, new type of applications have emerged, in order to face new technological and societal challenges, e.g. electronic voting protocols, secure routing protocols for mobile ad hoc networks, . . . These applications involve some features that are not taken into account by the existing veri cation tools, e.g. complex cryptographic primitives, privacy-type security properties, . . . This prevents us from modelling these protocols in an accurate way. Moreover, protocols are often analysed in isolation and this is well-known to be not su cient. In this thesis, we use formal methods to study these aspects concerning the veri cation of cryptographic protocols.