Power Minimization for Secure Multi-User ISAC System under Dual-Eavesdropper Threats

This study explores secure beamforming and artificial noise (AN) co-design in dual-threat integrated sensing and communication (ISAC) systems, where a base station simultaneously delivers confidential messages to multiple legitimate users and performs sensing operations. The system confronts two distinct eavesdropper categories: communication eavesdroppers (ComEves) intercepting data streams and sensing eavesdroppers (SenEves) acquiring sensitive target information. To counter these threats, we develop a joint optimization framework that coordinates transmit beamforming and AN generation at the ISAC transmitter. The optimization aims to reduce total transmit power while maintaining the required signal-to-interference-plusnoise ratio (SINR) levels for both communication receivers and sensing processes. Security enhancements are achieved through two key constraints: 1) communication secrecy rate thresholds preventing ComEve interception, and 2) mutual information limits protecting against SenEve sense. Comparative simulations reveal that the proposed scheme substantially reduces power consumption compared to conventional methods under equivalent operational constraints.