Authenticating civil UAV communications with post-quantum digital signatures

The integration of Unmanned Aerial Systems (UAS) into public airspace requires a secure UAV Traffic Management (UTM) system. Providing information security to communications is crucial for the UTM's operational safety. Ensuring the integrity and authentication of multicast data, such as emergency information and telemetry, is essential to prevent tampering and impersonation. Digital signatures provide an ideal solution for securing this data. However, implementing digital signature standards on small Unmanned Aerial Vehicles (UAVs) poses challenges due to hardware limitations. To address this, lightweight cryptographic algorithms have been developed for resource-constrained hardware. However, both lightweight and standard cryptographic algorithms are vulnerable to quantum computing attacks. To mitigate this vulnerability, post-quantum cryptographic primitives are being standardized. This study focuses on implementing post-quantum digital signature standards, Falcon and CRYSTALS-Dilithium, on constrained hardware resembling small UAVs. The performance of these algorithms in terms of computation time is evaluated considering real-time tasks during flights. The results demonstrate the feasibility of using unmodified standards on resource-constrained hardware alongside other priority tasks. Additionally, investigating algorithms with a reduced security level for telemetry broadcasts is considered. Falcon512 and CRYSTALS-Dilithium can both be used in this environment. Falcon512 is preferred due to its constancy in execution time and its shorter signatures and public keys.