Securing Wireless Network Coding against Pollution Attack at the Physical Layer

We take a physical layer perspective in detecting the falsely injected vector (pollution attack) and removing it from the polluted packet to restore the true coded packet in wireless network coding system. The proposed scheme builds on the maximum likelihood detection principle which is optimal in the sense of minimizing the probability of detection error. It discards only the faulty information and keeps the true coded packet, thereby making the retransmission of new coded packets unnecessary. This allows uninterrupted communication even under the attack. The proposed scheme is shown to provide a significant reliability gain over the cryptographic solution.