Research On Security Mechanism Of Wi-Fi Wireless Local Area Networks

Wireless Local Area Networks (WLAN) is applied to various fields widely for its flexible removability and high data rate. However, because the signals are transmitted through wireless channel, which can be captured and used easily by attacker, the main security problems are about identity authentication and data security. The identity authentication function insures that unauthorized users will not be accessed to WLAN; the data security function insures that the data in WLAN will not be used illegally. These are ideal double security mechanism, and the attention of this thesis is concentrated on data security mechanism.Based on the overall study of the structure, the standard and the security field's present state of WLAN, this thesis researched into the data security mechanism in general use in depth, WEP and TKIP, and then gave the analysis about security of them. Aimed at the data security mechanism which has highest security, CCMP, this thesis analyzed its encryption algorithm AES, operator schema CCM, encapsulation process and decapsulation process detailedly.Based on the theoretical research mentioned above, Aimed at the new demand of Block Ack and Frame Aggregation mechanism to CCMP, this thesis combined the merits of sequential and parallel implementary method and gave a modified method. Then, this thesis analyzed the modified method theoretically and emulated the modified CCMP with MATLAB. The theoretical analysis and simulation result show that the modified method not only meet the new demand of Block Ack and Frame Aggregation mechanism to CCMP, but also realize the same data security function as sequential and parallel method. The modified method has high feasibility.