Security Analysis And Improvement Of IEEE802.11i

Wireless LAN with the best visions of the future in all developing fields of wireless communication is attacked easily, for the communication medias used with the open media. It's a key problem which needs to be solved urgently on eatablishing and perfecting a kind of reliable-orientated wireless LAN security standard.The WLAN's security protocol standard are transiting from 802.11 to 802.11i. on the basic of looking back the 802.11 protocol simply, the paper analyed and studied completely on the security 802.11i protocol following ht aspects like this : security capbility discovery, authentication and access control, dynamic key management, data transfer. The result showed that using the CCMP protocol will enhance the data more safe and comprehensive. In addition, an authentication process, combining the 802.1X authentication and key management procedures, is performed to mutually authenticate the devices and generate a fresh session key for data transmissions. Therefor, an implementation of 802.11i protocols in a WLAN enhanced the security in the WLAN.Unfortunately, as the 802.11i does not emphasize availability, there are several loopholes. The paper mainly studied the unprotected management frame and control frame and anallysised the two kinds attack ways from the loophole:Man-in-the-Middle attack on the authentication stage,Dos attack on the 4-way Handshaking.The paper provided a new improved authentication methed based on the tunnel and used the source code (such as hostap,freeradius) to build a 802.1x/EAP-TTLS authentication platform and designed a client software testing the feasiability of tunnel authentication under linux system.The paper provided a new proved plan basing on the two kinds of plan improved and provided by others.To attain the goal of transmising the parameter which produce PTK safelyand identity authentication by using PMK and public key.What is achieved in this paper not only presents some formal analysis and effective solution to 802.11 i standard's leak, but also contributes to improvement of this standard.