Wireless communication is a fast-growing technology to provide the flexibility and mobility for the users. But it is less secure than wired networks, and then wireless security is becoming an important in product research and development area. In this paper, we provide a hardware-software co-design of robust security for WLAN. The design objective is to provide an efficient architecture that satisfies the constraints such as processing delay and data throughput required in standards. We have implemented the design supporting IEEE 802.11n. Finally, we show its results of implementation and evaluate performance.