Paint that blocks the Wi-Fi signal

I bought my neighbor a laptop for myself. I checked with Wi-Fi and found a signal. I connected to the point and happily used the free Internet for about half a year. Why all? Some careless employees of a nearby store, or the desks, simply forgot to password the point. Balbies

Why am I doing this? In addition, the password is not difficult to put on Wi-Fi. But as they say, there have been cases. Yes, and attacks on wireless networks has not been canceled. So, there is also an “elegant” solution for protecting an apartment / office from those who could potentially encroach on your radio waves. To do this, you need to buy a special paint (for $ 14 per kilogram) and paint the walls. The paint, which was developed at the University of Tokyo, added iron oxide and aluminum, which blocks radio waves at frequencies up to 182 GHz. That's for sure my home is my fortress. Even with respect to radio waves.

via mobbit.info