I. Introduction
Cooperative cognitive radio networks (CCRN) have emerged as a promising paradigm to address the spectrum scarcity and inefficiency in traditional wireless communication systems [1], [2], [3]. When primary users (PUs) are transmitting messages in the primary channel, secondary users (SUs) function as relays or friendly jammers to help PUs for transmission. In reward, when the primary channel is idle, SUs can opportunistically access and utilize underutilized spectrum bands licensed to primary users (PUs), while ensuring minimal interference to PU transmissions. The dynamic access feature of CCRN exposes it to many security threats. Physical layer security (PLS) has emerged as a promising approach to enhance the security of CCRNs by exploiting the characteristics of wireless channels [4], [5], [6].