Establishing secured communication among the intended users of wireless networks is a major concern. Especially, providing confidentiality is a critical requirement in a wireless communication system which is more susceptible to eavesdroppers. Prevailing cryptographic methods were proven to meet the security needs to some extent. Sophisticated encryption techniques cannot be always deployed in wireless devices, where the resources are limited. However, physical layer security is recently emerging into a promising paradigm to aid security in wireless networks by exploiting the dynamics of wireless channel. In this study, a physical layer security technique was proposed to enhance confidentiality which selects the modulation type adaptively, based on both channel signal‐to‐noise ratio and phase between transmitter and receiver. The performance of the proposed technique is evaluated for two types of eavesdroppers such as random and intelligent attackers through simulations. The proposed method improves confidentiality and throughput while maintaining the targeted symbol error rate than the existing algorithms.