One of the biggest criticisms levelled against Wi-Fi is that it’s wide open. Without additional security measures, Wi-Fi wireless LANs are open to anyone.
There are countless tales of private corporate LANs being accessed simply by putting a Wi-Fi-enabled laptop in the right place. Most Wi-Fi equipment is sold with a basic security standard, WEP (wired equivalent privacy), already there, but the ad hoc nature of many installations means WEP often isn’t even turned on. Even when it is, it won’t protect against a halfway competent hacker — the algorithm WEP is based on has been proven to be breakable, meaning regular changes to the WEP key are necessary for any semblance of security.
Other available security measures include making access to the LAN available only to the MAC (media access control) addresses of known, registered users. (The MAC address is a unique address assigned to each network card.)
Application of virtual private network encryption to the wireless LAN is another, albeit expensive, option and some vendors of wireless LAN gear have proprietary security in place — for example, Cisco’s LEAP (light extensible authentication protocol), which changes WEP keys faster than a hacker could crack the code. Further wireless LAN security standards from the IEEE are on the horizon, including TKIP (temporal key integrity protocol) and AED (advanced encryption system).
The CDMA and GPRS cellular data networks, by contrast, have extensive encryption measures in place and are very secure. Another drawback with Wi-Fi is interference.
Signals from clashing wireless LANs can wreak havoc and in such cases, the only option is to sit down and talk about it — because it operates in unlicensed spectrum, no one has pre-emptive rights.