Hide and Code: Session Anonymity in Wireless Line Networks with Coded Packets
The broadcast nature of the communication channel enables a malicious eavesdropper to gain information about connectivity and active sessions in a multi-hop wireless network. This can be achieved simply by overhearing the transmitted signals over the ether and analyzing their timings. Focusing on techniques that can meet information-theoretic criteria for session anonymity under traffic analysis attacks, the authors rely on a judicious choice of transmission schedules to conceal multicast or bidirectional unicast sessions from a global eavesdropper at any given point in time. A systematic approach for constructing the aforementioned transmission schedules for arbitrary network topologies is derived from an equivalent coloring problem in an auxiliary conflict graph.