Research Of Wireless Local Area Network's Key Distribution

The old secure framework of Wireless Local Area Network has many problems in three aspects: access control, authentication and algorithm of data encryption, such as:flimsiness of mechanism of Service Set Identity control and authentication ,and the data encryption and integrality of Wired Equivalent Privacy has some secure problems, so that its design goal can't be achieved. Furthermore, lack of effective key management is a blind spot of its secure design.Presently, there are two main secure technology of Wireless Local Area Network:Virtual Private Network and 802.1x. The application of Virtual Private Network in Wireless Local Area Network has been limited, because the interrupt of Virtual Private Network link influences continuity of operation in roaming and handoff case. 802.1x protocol is suitable for Wireless Local Area Network, because of its flexibility and adaptability for new authentication method. IEEE 802.11i work group has engaged in many researches of application of 802.1x protocol. And they put forward a new generation of secure framework, named Robust Security Network.Robust Security Network has made up blankness of the key management. And it includes two key hierarchy:pairwise key hierarchy and group key hierarchy. 4-way handshake and group key handshake protocol are used to distribute the two kinds of key. But the introduction of the two protocols makes delay of roam bigger. And quality of service in roam is played down. There are two measures to reduce it. First, the start point of key distribution is advanced from behind authentication to before authentication. The key distribution starts from association. Second, the group key distribution is joined into pairwise key's distribution. The individual process of group key's distribution is cancelled. These improved measures are in favor of reducing the delay in roaming case. And the compatibility of them for Robust Security Network's protocol of key distribution is kept.