Abstract: A novel approach for ensuring confidential wireless communication is proposed and analyzed from an information-theoretic standpoint. In this method, the legitimate receiver generates artificial noise (AN) to impair the intruder’s channel. This method is robust because it doesn’t need feedback of CSI and can withstand multi-antenna or colluding eavesdroppers. Furthermore, using the average signal-to-noise ratio, which is only a function of the path-loss, we determine the insecure regions, which is the geographical regions where Eve may decode the secret message. The secure region is the region where Eve cannot decode the message. To improve the probability of communicating securely, the target of our design can be the reduction of the insecure region. For each target value of the secrecy capacity, we derive the secure region for both SISO and MIMO systems when the channels are unknown to the transmitter. Analysis and simulation results in practical environments show that the proposed method has a good performance.