Physical Layer Security in NFC: Advances, Potential Toward 6G Wireless Communications

With the advent of sixth-generation wireless communication, the development of extremely large-scale antenna arrays (ELAA) and terahertz (THz) frequency bands has significantly advanced research into near-field communication (NFC). Unlike traditional far-field communication (FFC), which is based on a plane wave propagation model, NFC capitalizes on its unique spherical wave propagation characteristics to precisely focus signals, thus attracting considerable attention. However, the inherent complexity of NFC channels and the security threats associated with short-range communications present significant challenges. To better reflect realistic scenarios, this article assumes that the position of potential untrusted nodes is uncertain, allowing dynamic adjustments to attack strategies. Consequently, legitimate users may be exposed to risks such as passive eavesdropping or active interference. In response to these concerns, this article addresses the issue of physical layer security (PLS) in NFC by leveraging key technologies including resolution enhancement, deployment of extremely large-scale reconfigurable intelligent surfaces (XL-RIS), and pinching antennas to propose methods for enhancing system security. Finally, this article outlines feasible solutions to anticipated future challenges, providing new insights into the realization of secure communication in the near-field.