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Location Privacy in Mobile Networks

This master thesis presents a client-server system for protecting the anonymity and location privacy of mobile network users against a passive network-side adversary. The server provides a pool of UICCs – technological successors to SIM cards. Users’ cellphones rely on those UICCs for accessing a mobile network. Through simultaneous, coordinated switching to new UICCs, groups of users in the same mobile radio cell become indistinguishable to the adversary. The system’s performance was evaluated based on simulated vehicle traffic. An increase of the number of users led to a rise in coordinated UICC switching, higher distance errors, and a decrease of user identification ratios. The system is capable of enhancing the anonymity and location privacy of its users against a passive adversary, provided that the opponent does not track mobile phones based on their device identities.