4This paper measures outage probability (OP) and intercept probability (IP) of a secondary secure network in a relaying underlay spectrum-sharing cognitive radio (USS-CR) system. In this scheme, one of successful secondary relays is chosen to obtain the highest signal-to-noise ratio (SNR) at a secondary destination. This paper considers the case where channel state information (CSI) of the eavesdropping links is not available. The OP and IP performance of the considered scheme is calculated via analysis and simulations, under impact of hardware noises, over Rayleigh fading channels Index Terms4Underlay spectrum-sharing cognitive radio, physical-layer security, outage probability, intercept probability, hardware impairments.