The very fundamentals of WLAN that make this technology disruptive also make it a challenge in terms of security. LANs are based on the wired fundamentals, especially in terms of confidentiality and access control. In the wired world, the wires protect the communication to some extent?one needs to connect to a physical jack to communicate. In the wireless world, however, the signals are in the air, open for all to listen. Also, the wireless signals cross the physical boundaries of an organization. This same signals-in-the-air property of WLANs makes it important that there be strong confidentiality (based on encryption) and access control based on authentication mechanisms. In some sense, most of WLAN security is about achieving this balance.