Exploring Physical-Layer Anti-Privacy-Theft Capacity in Wireless Networks

This paper studies wireless physical-layer impact on anonymity, considering information sniffing over the air as a threat model. Information can leak at the communication physical layer even though encryption is employed. A discrete memoryless channel as system model is used to reflect the fighting between the users and sniffer. Two anonymity metrics are defined and examined based on the probabilistic model. The sniffer is equipped with a classifier and a number of sniffing receivers in the field in order to figure out who is sending packages based on received signal strength (RSS). Four physical-layer anti-sniffing techniques are considered. Computer simulation is used to generate numerical results, considering a wireless uplink transmission system with time-division fashion in a lognormal fading environment. Performances for the best, worst and uniform probability distributions of users' presence are provided. The observations suggest that there could be a potential risk of privacy leakage at the physical layer and also a great potential to guard privacy using physical-layer means.