Integrated sensing and communication (ISAC) enables the efficient sharing of wireless resources to support emerging applications, but it also gives rise to new sensing-based security vulnerabilities. Here, potential communication security threats whereby confidential messages intended for legitimate users are intercepted, but also unauthorized receivers (Eves) can passively exploit target echoes to infer sensing parameters without users being aware. Despite these risks, the joint protection of sensing and communication security in ISAC systems remains unexplored. To address this challenge, this paper proposes a two-layer dual-secure ISAC framework that simultaneously protects sensing and communication against passive sensing Eves and communication Eves, without requiring their channel state information (CSI). Specifically, transmit beamformers are jointly designed to inject artificial noise (AN) to introduce interference to communication Eves, while deliberately distorting the reference signal available to sensing Eves to impair their sensing capability. Furthermore, the proposed design generates artificial ghosts (AGs) with fake angle-range-velocity profiles observable by all receivers. Legitimate receivers can suppress these AGs, whereas sensing Eves cannot, thereby significantly reducing their probability of correctly detecting the true targets. Numerical results demonstrate that the proposed framework effectively enhances both communication and sensing security, while preserving the performance of communication users and legitimate sensing receivers.

翻译：集成感知与通信（ISAC）能够高效共享无线资源以支持新兴应用，但同时也引发了新的基于感知的安全漏洞。此处不仅存在合法用户预期接收的机密信息被拦截的潜在通信安全威胁，未经授权的接收器（窃听者）还可被动利用目标回波来推断感知参数，而用户对此毫无察觉。尽管存在这些风险，ISAC系统中感知与通信安全的联合保护机制仍未得到充分探索。为应对这一挑战，本文提出了一种双层双重安全ISAC框架，该框架能在无需获取信道状态信息（CSI）的条件下，同时保护感知与通信安全，抵御被动感知窃听者与通信窃听者的攻击。具体而言，通过联合设计发射波束成形器，一方面注入人工噪声（AN）以对通信窃听者引入干扰，另一方面则有意扭曲可供感知窃听者利用的参考信号，从而削弱其感知能力。此外，所提设计还能生成具有虚假角度-距离-速度特征的人工幻影（AGs），且所有接收器均可观测到这些幻影。合法接收器能够抑制这些AGs，而感知窃听者则无法做到，从而显著降低其正确检测真实目标的概率。数值结果表明，所提框架在保障通信用户与合法感知接收器性能的同时，能有效提升通信与感知的双重安全性。