Anti-WiFi paint blocks your wireless signal from intruders

How can you protect against a hacker neighbor who keeps hooking up to your wireless internet signal? The solution: paint the walls of your house!

Researches at the University of Tokyo have developed a special paint that blocks Wi-Fi signals. The trick is in the mixture of paint and particles of aluminum-iron oxide. The metal particles resonate at the same frequency as Wi-Fi waves, thus the signals can’t pass through this type of paint.

For instance, if you paint the walls of a space in your house, let’s say the bathroom, the wireless network inside the bathroom will remain in the bathroom. The magic works both ways so you also won’t be able to access anything that’s beamed on the outside.

The idea is not entirely new — similar paints have existed before — but this paint is the first to block signals up to 100 GHz. Most Wi-Fi technologies used today work at a frequency of 2.5 GHz. According to the engineers, the paint is a quick and cheap method of protection against unauthorized users, as opposed of investing into expensive software encryption systems.

The head of the project, Shinichi Ohkoshi, in the interview for BBC says that he is not yet completely satisfied with the result and they are already working on a paint that can block signals up to 200 GHz.

According to Ohkoshi, the paint isn’t just of interest to people who want to limit their Wi-Fi access. For example, movie theaters are interested in a way that would prevent cell phones from ringing during movie screenings. There are other uses as well: in medicine, they could transmit large amounts of data from a medical device to a computer inside a painted room that would be shielded from stray electromagnetic radiation from the outside.

The cost? According to the maker, the anti wifi paint will cost about $15 per kilogram.