Abstract: Cooperation among multiple cognitive users provides an improvement for primary user detection. However, this paradigm also poses new security vulnerabilities in cognitive radio system. Specifically, malicious users falsify sensing data can decrease cooperative sensing performance. In this paper, we propose a secure cooperative sensing scheme to resist malicious user attack. The proposed scheme is performed in both user-wise and time-wise detections with trusted nodes assistance, where the stability of the scheme in the context of several malicious users is guaranteed. Simulations show that the performance of our scheme outcomes the one proposed by Kaligineedi. The proposed scheme can work effectively in the scenario where a half of the users are malicious.