Integrate sensing and communication (ISAC), which enables the radar sensing and wireless communication to be integrated to share the spectrum, hardware infrastructure and signal processing architectures, has been recognized as one promising technical supporter of providing spectrum- and energy-efficiency services for 6G network. However, due to the shared usage of the spectrum and broadcast nature of wireless medium, ISAC systems are facing multiple security threats and attacks that may result in information leakage, service outage and network congestion. To address above security issues, in this project, we propose a novel secure ISAC (S ISAC) framework for future wireless networks aimed at providing secure and reliable communication services with precise and accurate sensing simultaneously in the following three work packages. In the first work package (WP), a covert ISAC framework will be proposed to hide the communication signal into multiple other signals, including radar signal, noise signal and jamming signal and ensure the covert communication without being detected by the malicious adversary. Next, efficient physical layer security (PLS) strategies will be developed in the second WP to against the passive eavesdropping attacks, which are launched by half-duplex eavesdroppers with the capability of decoding the communication signals. Then, to against more harmful active eavesdropping attacks that are launched by full-duplex eavesdroppers who are capable of overhearing the communication signal and sending malicious jamming signal simultaneously, robust PLS strategies will be designed by satisfying the sensing requirements in the third WP. Finally, extensive simulation results will be provided to validate the effectiveness and robustness of our proposed S-ISAC design.