Security Analysis Of 802.11 WLAN

IEEE ratified the WLAN 802.11 standard in Oct 1997, which was a landmark that WLAN technology went from the laboratory into the market. As the 802.11 b, 802.11 a and 802.11g standards were ratified by IEEE, products consistent with these standards became popular in the market. With the flourish of WLAN market, people are concerned about the WLAN security more than ever. Data transmitted in WLAN over high frequency radio is subject to eavesdropping, furthermore, physical media access control measures don't adapt to WLAN.By sustentation fund from National High Technology Research and Development Project (863 project) grant NO. 2002AA143021, we do an in-depth study on the security in WLAN, which is a component of the security technology in Broadband Wireless IP network. In this paper, we first analyze the mechanism of the present security protocols. We point out their merits and flaws, and present some attacking ways by means of the design flaws in the protocols. Secondly, we analysis the major elements in IEEE 802.1li, including key management authentication system and data privacy protocols. Basing on the analysis mentioned above, we design an authentication protocol well adapted to WLAN. With the development of WLAN market, roaming is becoming an important scenario. With the analysis of the requirements of roaming, we draw the conclusion that none of the present protocols meet the special requirements of roaming. An authentication protocol for WLAN is presented to support roaming and its performance and security are analyzed. The proofs of the two authentication protocols presented in the paper are obtained.