In Vehicle-to-Everything (V2X) systems, reliable and secure information exchange plays a pivotal role in road safety and traffic management. Due to the open nature of the wireless medium and the constant or intermittent mobility of vehicles, the security of transmissions in V2X is more challenging compared to traditional wireless networks. Physical layer security (PLS) leverages the inherent randomness of wireless communication channels to ensure the confidentiality and security of information transmission. Current PLS schemes in integrated communications and sensing (ISAC) enabled V2X systems is to utilize communication interference to significantly impact the eavesdropping channel more than the legitimate channel. However, in an ISAC-enabled V2X system, it is crucial to prioritize and address the issue of interference coupling as it significantly impacts the confidentiality and security of information exchange. This goes beyond simply relying on the communication interference. Until now, no discussions or studies on integrating security with ISAC (Seucue-ISAC) in ISAC-enabled V2X systems, specifically regarding the exploitation of sensing interference or coupling interference. In this article, we provide a comprehensive review on PLS metrics and security threats encountered in V2X communication. And then, we discuss and analyze four popular PLS techniques and the main challenges associated with their implementation in ISAC-enabled V2X systems. Finally, we share our vision for PLS studies in ISAC-based V2X systems to promote Secure-ISAC.

翻译：在车联网（V2X）系统中，可靠且安全的信息交换对道路安全和交通管理起着关键作用。由于无线介质的开放性以及车辆的持续或间歇性移动，V2X传输的安全性相比传统无线网络更具挑战性。物理层安全（PLS）利用无线通信信道的固有随机性来确保信息传输的机密性和安全性。当前，在集成通信与感知（ISAC）赋能的V2X系统中，PLS方案通过利用通信干扰来显著影响窃听信道，使其劣于合法信道。然而，在ISAC赋能的V2X系统中，优先解决干扰耦合问题至关重要，因为它严重影响信息交换的机密性和安全性。这一问题超出了单纯依赖通信干扰的范畴。截至目前，尚无针对ISAC赋能的V2X系统中将安全与通感一体化（Secure-ISAC）相结合的研究或讨论，特别是关于利用感知干扰或耦合干扰的探索。本文对V2X通信中遇到的PLS指标和安全威胁进行了全面综述。随后，我们讨论并分析了四种流行的PLS技术及其在ISAC赋能的V2X系统中实现所面临的主要挑战。最后，我们展望了基于ISAC的V2X系统中的PLS研究方向，以推动Secure-ISAC的发展。