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Abstract

Unmanned aerial vehicle (UAV) swarms rely on distributed coordination and cooperative communication to achieve scalability, extend operational range, and support complex applications such as persistent surveillance and real-time message transmission. Although wireless networks such as Radio Frequency (RF) and WiFi are commonly used to enable UAV-to-UAV and UAV-to-Ground Control Station (GCS) communication, they introduce inherent security challenges. In particular, MAVLink, the predominant communication protocol in UAV systems, provides message integrity and authentication mechanisms, but lacks built-in encryption, leaving the transmitted telemetry messages susceptible to eavesdropping. In our prior work, we proposed the MAVShield cipher, which is a lightweight encryption framework for MAVLink communications. In this study, five encryption algorithms MAVShield, Advanced Encryption Standard in counter mode (AES-CTR), Speck in counter mode (Speck-CTR), ChaCha20, and Rabbit are integrated into the communication architecture of four custom built UAVs to establish robust and secure communication links for UAV-to-UAV interactions over both RF and WiFi channels. The performance of the encryption algorithms is evaluated by conducting extensive flight tests using a UAV swarm hardware testbed. The encrypted telemetry data is utilized to achieve autonomous formation control and collision avoidance during flight operations conducted using the testbed. For collision avoidance, we propose a modified artificial potential field (APF) algorithm that computes attractive and repulsive forces directly in geodetic coordinates, eliminating the need for Cartesian transformations, and employs a gradually activated repulsive force to achieve smooth, jitter-free trajectories without local minimum trapping within the operating region of interest. Key performance metrics such as CPU utilization, memory consumption, and packet delivery ratio (PDR) are measured for each encryption scheme. Our results show that despite incorporating additional security mechanisms, MAVShield maintains performance levels comparable to unencrypted communication, while outperforming the other four encryption schemes in terms of overall efficiency. Furthermore, algebraic cryptanalysis and Wireshark-based traffic analysis confirm its strong resistance to key recovery attacks and its ability to preserve telemetry confidentiality. Overall, the results indicate that MAVShield is an efficient and secure solution for UAV swarm communication.