Physical-Layer Challenge-Response Authentication for Drone Networks

Authenticating the communications among drones operating as a network (or a swarm) is crucial for the control of the network. When drones are in turn supporting communications with other ground devices (e.g., in non-terrestrial networks), all nodes in the network need to be authenticated for end-to-end security. The absence of a reliable fixed network architecture among drones, which are only connected by wireless links, calls for new authentication mechanisms that can complement or be used as alternatives to those offered by cryptography. We propose a challenge-response (CR) physical-layer authentication (PLA) mechanism, where, upon a transmission request from a transmitting drone, referred to as Alice, Bob either asks Alice to move in a specific (randomly chosen) position or moves to a (randomly chosen) position: in both cases, changes in the propagation environment are controlled by Bob. Then, the message is transmitted and Bob estimates the channel from the received signal and verifies that it is compatible with the positions assumed by Alice and Bob. Note that Bob may represent a group of drones that cooperate for authentication. We discuss several security challenges to this CR PLA mechanism and compare them with existing approaches. Preliminary results on the performance of the proposed authentication scheme are presented, showing the advantage of the CR PLA approach.