A Lightweight Hybrid Post-Quantum Authentication Protocol for Resource-Constrained UAV–GCS Communications

Resource-constrained unmanned aerial vehicle–ground control station (UAV–GCS) communications face substantial post-quantum authentication costs, expensive cryptographic operations triggered by invalid requests, and key-state desynchronization during rekeying. To address these problems, this paper proposes QUAD, a lightweight hybrid post-quantum authentication and key agreement protocol. QUAD combines request pre-authentication, hybrid key establishment, and mutual key confirmation to reject invalid requests before costly cryptographic operations. It also allows a bounded transition period for receiving records under the old and new keys to mitigate key-state inconsistencies caused by link disruptions. Confidentiality and authentication are analyzed using ProVerif, while cryptographic and communication overhead, denial-of-service scenarios, and key-update behavior are evaluated on a Raspberry Pi platform. Under the specified security model, QUAD satisfies the tested authentication and confidentiality properties, reduces the computational burden of invalid requests, and improves bidirectional communication continuity under selected packet-loss conditions. These findings support its feasibility for post-quantum security in resource-constrained UAV–GCS links.