Integrated sensing and communication (ISAC) has emerged as a pivotal technology for next-generation wireless networks, enabling simultaneous data transmission and environmental sensing. However, existing ISAC systems face fundamental limitations in achieving high-resolution sensing while maintaining robust communication security and spectral efficiency. This paper introduces a transformative approach leveraging stacked intelligent metasurfaces (SIM) to overcome these challenges. We propose a multi-functional SIM-assisted system that jointly optimizes communication secrecy and sensing accuracy through a novel layered optimization framework. Our solution employs a multi-objective optimization formulation that balances secrecy rate maximization with sensing error minimization under practical hardware constraints. The proposed layered block coordinate descent algorithm efficiently coordinates sensing configuration, secure beamforming, communication metasurface optimization, and resource allocation while ensuring robustness to channel uncertainties. Extensive simulations demonstrate significant performance gains over conventional approaches, achieving 32-61\% improvement in sensing accuracy and 15-35\% enhancement in secrecy rates while maintaining computational efficiency. This work establishes a new paradigm for secure and high-precision multi-functional wireless systems.

翻译：集成感知与通信（ISAC）已成为下一代无线网络的关键技术，能够同时实现数据传输与环境感知。然而，现有ISAC系统在实现高分辨率感知的同时，难以兼顾通信安全性与频谱效率。本文提出一种利用堆叠智能超表面（SIM）的变革性方法以应对这些挑战。我们设计了一种多功能SIM辅助系统，通过新颖的分层优化框架联合优化通信保密性与感知精度。该方案采用多目标优化模型，在实际硬件约束下平衡保密率最大化与感知误差最小化。所提出的分层块坐标下降算法高效协调感知配置、安全波束成形、通信超表面优化与资源分配，同时确保对信道不确定性的鲁棒性。大量仿真结果表明，相较于传统方法，本方案在保持计算效率的同时，感知精度提升32-61%，保密率提高15-35%。本研究为安全高精度的多功能无线系统建立了新范式。