With the ever increasing volume of information over wireless medium, security has assumed an important dimension. The security of transmitted data over a wireless channel aims at protecting the data from unauthorized intrusion. Wireless network security is achieved using cryptographic primitives. Some properties that give encryption mechanism their cryptographic strength also make them very sensitive to channel error as well. Therefore, security for data transmission over wireless channel results in throughput loss. Tradeoff between security and throughput is always a major concern in wireless networks. In this paper, a Link Adaptive Encryption scheme is evaluated that adapts to channel variations and enhances the security level of WLANs without making any compromise with the network performance.