Due to great efficiency improvement in resource and hardware space, integrated sensing and communication (ISAC) has gained much attention. In the paper, the physical layer security (PLS) of ISAC system under communication eavesdropper together with sensing eavesdropper is investigated. The system secrecy rate is maximized by transmit beamforming design of communication and sensing signals when taking sensing security, sensing performance and transmit power constraint into consideration. To deal with the formulated non-convex optimization problem, the successive convex approximation (SCA) together with the first-order Taylor expansion and semidefinite relaxation (SDR) is utilized. Additionally, it is theoretically validated that the SDR does not yield sub-optimality in the paper. Thereafter, an iterated joint secure beamforming algorithm against communication and sensing eavesdroppers is proposed. Simulation results validate the effectiveness and advance of the proposed scheme.

翻译：集成感知与通信（ISAC）因在资源和硬件空间上的高效性提升而备受关注。本文研究了在存在通信窃听者和感知窃听者情况下ISAC系统的物理层安全（PLS）问题。在考虑感知安全性、感知性能和发射功率约束的条件下，通过设计通信信号与感知信号的发射波束赋形，最大化系统的保密速率。为处理所建立的非凸优化问题，本文采用了逐次凸逼近（SCA）结合一阶泰勒展开与半定松弛（SDR）的方法。此外，本文从理论上验证了SDR不会产生次优性。进而提出了一种联合迭代安全波束赋形算法，以对抗通信与感知窃听者。仿真结果验证了所提方案的有效性与优越性。