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Widespread mobile network connectivity has changed society and, consequently, increased our dependency on its proper functioning for transportation, safety, finance, and more. This thesis is concerned with improving the security of mobile networks and focuses on two such instances: vehicular and cellular networks. We aim at mitigating certain security risks even in the presence of strong attackers, which could be manifested in the form of internal malicious agents in cellular network providers or connected vehicles compromised with malicious software, to mention a couple of examples. Within this scope, we target two main challenges: proving that a selected set of security protocols in vehicular and cellular networks guarantee the expected security properties and improving the trustworthiness of location information shared by neighbouring vehicles.

Our contributions to security protocols involve employing formal methods to verify security properties in the vehicular communication protocol Ensemble and in the fifth generation of cellular networks (5G). The Ensemble protocol aims to enable multi-brand truck platooning and is currently in a prestandardisation effort in Europe. We report a potential weakness that was resolved in the latest versions and verify that strong security properties are fulfilled. To make verification tractable, we propose a strategy based on the hierarchy of cryptographic keys which may also be employed in protocols that have similar keying structures. In 5G, we identify a weakness that could be exploited to frame people into suspicion of serious crimes when lawful interception operations are conducted. We then design the …