Volume 25 (2017) Pages 288-295
WEP has serious vulnerabilities, and they cause various key recovery attacks. Although a more secure protocol such as WPA2 is recommended, according to each research by IPA and Keymans NET, WEP is still widely used because of the lack of knowledge about security of the wireless LAN. On the other hand, it takes large costs to replace a wireless LAN equipment in large-scale facilities. They need a secure method which can be used on their equipment by updating the firmware of WEP. In 2011, Morii, one of us, et al. showed IVs which prevented the Klein attack, the PTW attack, and the TeAM-OK attack. However, they did not present how to obtain such IVs and evaluate security of them. This paper shows the secure method of WEP and how to use it as fast as WEP. We show an IV which prevents the establishment of previous key recovery attacks. Moreover, we show how to use our IV efficiently on the operation of WEP. Our method requires about 1.1 times the processing time for the encryption than WEP. As a result, our method can prevent previous key recovery attacks and realize communication as fast as WEP.