Covert Communications Meet 6G NTN: A Comprehensive Enabler for Safety-Critical IoT

The integration of non-terrestrial networks (NTNs) in 6G enables seamless connectivity and unleashes the potential of stringent Internet of Things (IoT) services worldwide. Among these, safety-critical IoT aims to provide ubiquitous service along with comprehensive protection against diversified over-the-air threats, which requires high-security technology under the unique constraints of NTNs. As a promising secure transmission technology rooted in information theory, wireless covert communication can conceal the presence of transmission so as to eliminate possible attack threats. In this article, we point out that the continuous evolution of covert communication paves a comprehensive avenue to tackle the complicated security challenges of safety-critical IoT in 6G NTN. We elucidate several typical security threats that may be encountered in NTN IoT and analyze how covert communication can resist these security vulnerabilities through its endogenous potential. Further, we propose an artificial intelligence-based three-participant collaborative-adversarial network to strike a balance between communication efficiency and covertness performance. Finally, some future research directions and challenges of covert communication are discussed.