Anti-Wi-Fi paint keeps your wireless signal to yourself

Don't like the idea of your neighbors rudely snooping on the wireless signal you slaved to pay for from the lazy comfort of their living room? It's not just about slowing down your connection; while they're downloading Mad Men via bittorrent, you could be on the hook for their actions.

Wireless security and encryption systems are fraught with problems and insecurity, and other methods to restrict your signal to a small area are cumbersome at best.

Enter a new solution: Anti-Wi-Fi paint.

The idea is simple: Use a special paint on walls where you don't want wireless to pass through (say the exterior of your house). The secret is mixing aluminum-iron oxide particles in with the paint. The metal particles resonate at the same frequency as Wi-Fi and other radio waves, so signals can't pass through the thin layer of pigment. Outsiders would simply be unable to access your wireless network, just as you, inside the house, won't be able to interlope on anything beamed on the outside.

Developed by the University of Tokyo, the paint is said to be the first that can block radio frequency in higher spectra where Wi-Fi and other higher-bandwidth communications occur rather than just low-frequency wireless like FM radio. Most Wi-Fi technologies operate at 2.4GHz; the Tokyo paint can reportedly block frequencies all the way up to 100GHz, with a 200GHz-blocking paint now in the works.

The paint isn't just of interest to those concerned about wireless leaking out of the building. Movie theaters have long been interested in finding a legal way to keep cell phones silent during screenings. Electronic jammers that actively block wireless signals are illegal, but passive materials that prevent wireless signals from getting through are not. Since the wireless-blocking paint can also block the lower-frequency signals that cell phones use, addled mobile junkies would have no outlet for reaching the outside world.

Some aren't convinced that anti-Wi-Fi paint makes a lot of sense for a secure situation, though. Says one engineer, "Surely the thought of having to redecorate a building in order to provide Wi-Fi security is more costly and complex than the security functionality available in even the cheapest of Wi-Fi access points..."

Good point.