Secure Communication of Integrated Air-Space-Ground-Maritime Networks: Technologies, Application and Challenges

The integrated air-space-ground-maritime network (ASGMIN) refers to the interconnected and collaborative integration of resources and information across three-dimensional spatial domains. This integration aims to establish an efficient and seamless service system, playing a vital role in achieving intelligence and global coverage in the sixth-generation (6G) era. This article explores the concept, architecture and secure communication technologies of the ASGMIN. It begins by highlighting the limitations of existing networks, including issues with coverage, resource utilization, stringent application requirements. The article then introduces the multi-dimensional integration of ASGMIN, combining air, space, ground, and maritime networks to achieve full-area coverage and intelligent collaboration. It further analyzes the technical advantages of ASGMIN in terms of full-area coverage, high-speed intelligence, safety, reliability, and flexible deployment. The article also highlights its wide-ranging in national security, disaster relief, intelligent transportation, and environmental monitoring. To address security threats, this article discusses four key security technologies in detail: physical layer security, physical layer authentication, covert communication, and reconfigurable intelligent surface. These technologies enhance security by improving channel quality differences, leveraging unique physical-layer characteristics for device identity verification, reducing signal detection probability, and optimizing the channel environment, respectively. This article also summarizes the potential and challenges of these technologies in areas like anti-eavesdropping, anti-interference and complex network applications. It proposes future research directions, including artificial intelligence (AI)-based dynamic security management, multi-level security policy coordination and cross-layer protocol standardization. In conclusion, this article emphasizes the critical role of innovative secure communication technologies in addressing the evolving needs of different networks.