Physical layer security and covert communication in UAV-ISAC networks: A comprehensive survey

Under the rapid development of the low-altitude economy, while unmanned aerial vehicle-assisted integrated sensing and communication (UAV-ISAC) significantly enhances perception accuracy and communication reliability in dynamic network environments, it also faces security threats from information leakage and malicious interference in open electromagnetic environments, making physical layer security (PLS) and covert communication technologies particularly crucial. This work reviews recent advances in PLS and covert communication techniques for UAV-ISAC networks. It first introduces the basic architecture and typical application scenarios of UAV-ISAC networks, and then discusses two main aspects: For PLS, key technologies are highlighted. including channel characteristic-based design, cooperative communication, resource allocation, and reconfigurable intelligent surface (RIS)-assisted approaches. For covert communication, representative solutions are summarized across spatial domain, power domain, time-frequency domain, RIS, and artificial intelligence (AI)-aided methods, along with their technical characteristics and system performance under complex scenarios. Finally, the current challenges in PLS and covert communication for UAV-ISAC networks are analyzed, and the future development potential of network security in UAV-ISAC systems is discussed.