Objectives: To propose relay selection plans for a CR network. A network of Cognitive Radio (CR) is considered. It comprises of one Secondary Transmitter (ST), a set of multiple Secondary Relays (SRs) and one Secondary Destination (SD) and an eavesdropper is also present. Here the ST is transmitting to SD assisted by SRs, while eavesdropper attempts interception of secondary transmission. Methods: Care is exercised in selecting relay to protect ST-SD transmission. Protection is against eavesdropper both single-relay as well as multi-relay aid that. In particular, possibly best SR gets chosen in a singlerelay type selection to assist transmission of secondary type. Multi-relay selections invoke multiple SRs for simultaneous forwarding of transmission of ST to SD. Findings: Both probabilities of intercept as well as outage are analyzed for the put forth single-relay as well as relay of multi type selecting methods meant for transmission of secondary type. This relies upon the realistic kind of sensing of spectrum. Evaluation of performance is done on the classic type transmission of direct kind and also the approaches of artificial noise based for comparing them with proposed schemes of relay selection. Improvements/Applications: It shows that relaxing intercept probability requirement improves performance of outage related to transmission of direct type, schemes for selection of relay and also-based on noise of artificial type-scheme and vice versa. This leads to the implication that a trade-off is done between reliability and security of secondary transmission when eavesdropping attacks are present. This implication is popularly coined as security to reliability - a trade-off (SRT). Also it is demonstrated that SRTs schemes of single-relay as well as multi-relay selection are normally better compared to classic direct transmission. It explicitly demonstrates the salient features of selection of relay scheme in question. This is related to offering protection to transmissions of secondary type from attacks of eavesdropping. Apart from this there is an increase in SRs' count, obviously SRTs about relay of single type in question now as well as relay of multi type selection method improve substantially.