Wireless Local Area Network is the result of computer and wireless communication, which uses the wireless channel as the transmission medium and has many advantages compared with wire network. WLAN is used more and more widely and the security is more and more important. Network risk can be infected by three aspects, such as: the frangibility of network, the vicious menace form exterior, the value of information. It analyzes the basic concept and characteristics of WLAN and studies the security mechanism from three aspects which include physical security, general security and enhanced security. It studies the general security form three technologies, such as: Services Set Identifier, MAC Address filtration, Wired Equivalent Privacy. It analyzes enhanced security from three aspects, such as: WPA, 802.11i, WAPI. It analyzes the main encrypion algorithm, such as: Temporal Key Integrity Protocol (TKIP), Counter-Mode/CBC-MAC Protocol (CCMP). At last, it studies the standard of china which is Wireless LAN Authentication and Privacy Infrastructure (WAPI).
