Together We are Strong: Securing Industrial Wireless Networks with Overhearing Nodes

Recent works have shown that the wireless link between two nodes is neither a shared secret nor unforgeable by an adversary - questioning the effectiveness of many physical layer security mechanisms. In this work, we argue that physical layer security is still valuable when multiple nodes combine their measurements of overheard adversarial transmissions. This assumption is applicable to, e.g., industrial wireless networks, where nodes are spatially close and wireless links are unique. First, we design a novel physical layer adversary detection algorithm particularly suited for the scenario of multiple sensing nodes. Second, we evaluate our algorithm with real-world measurements, which show that already four detecting nodes are sufficient to significantly increase the detection performance.