  LiDAR systems that rely on classical signals are susceptible to
intercept-and-recent spoofing attacks, where a target attempts to avoid
detection. To address this vulnerability, we propose a quantum-secured LiDAR
protocol that utilizes Gaussian modulated coherent states for both range
determination and spoofing attack detection. By leveraging the Gaussian nature
of the signals, the LiDAR system can accurately determine the range of the
target through cross-correlation analysis. Additionally, by estimating the
excess noise of the LiDAR system, the spoofing attack performed by the target
can be detected, as it can introduce additional noise to the signals. We have
developed a model for target detection and security check, and conducted
numerical simulations to evaluate the Receiver Operating Characteristic (ROC)
of the LiDAR system. The results indicate that an intercept-and-recent spoofing
attack can be detected with a high probability at a low false-alarm rate.
Furthermore, the proposed method can be implemented using currently available
technology, highlighting its feasibility and practicality in real-world
applications.
