As drones become increasingly embedded in civilian systems—from environmental monitoring to disaster relief—the security of their wireless links has emerged as a critical concern. Spoofing and jamming attacks can interfere with navigation or inject false messages, making robust authentication mechanisms essential for safe drone operations. This study introduces a physical-layer Challenge–Response Authentication (CR-PLA) protocol specifically designed for drone communications. Unlike cryptographic methods, which require computational resources and increase communication overhead, CR-PLA leverages the physical properties of the wireless channel to verify a drone’s identity with low energy consumption.
The protocol works in two stages. In a setup phase, the legitimate drone (Alice) flies through predefined positions, allowing the receiver (Bob) to record reference channel gains from each location. During the authentication phase, Bob secretly chooses a sequence of positions and sends them to Alice as a challenge. Alice moves to these positions and sends pilot signals. Bob compares the measured channel gains with the stored reference values to determine whether the message came from Alice or an intruder drone (Trudy). A key contribution of the paper is the game-theoretic optimization of both Bob’s and Trudy’s strategies. Their interaction is modeled as a zero-sum game in which Bob aims to minimize the misdetection (MD) probability while Trudy attempts to maximize it. The authors derive Nash Equilibrium (NE) strategies for both players and show that optimal strategies involve selecting positions independently across rounds. This allows multi-round authentication to significantly reduce MD probability.
The paper also addresses the energy cost of drone movement. Since each position change consumes energy, the authors propose three methods to minimize travel distance while staying within the NE strategy space: an optimal multi-round approach, a simplified per-position method, and a single mixed-strategy solution. Results show that the simplified method achieves performance close to optimal while being computationally efficient. Simulation results demonstrate the protocol’s strong performance across urban and rural environments, different shadowing levels, drone altitudes, and multi-drone (“swarm”) scenarios. Even with only a few rounds of authentication, the system achieves very low misdetection rates—for example, around 10⁻³ with three rounds. Higher shadowing variance further enhances security by increasing channel diversity. Overall, the work presents a practical and energy-efficient authentication mechanism for drones, backed by rigorous statistical modeling and game-theoretic analysis. It shows how physical-layer properties and strategic optimization can jointly strengthen the security of future aerial communication systems.
Challenge-Response to Authenticate Drone Communications A Game Theoretic Approach