Lock yourself in a cage

 

For real top-of-the-line protection, you need to get yourself a Faraday cage. This is a box made of conductive material. Properly constructed, it will block enough of your computer’s EM output that not even a military-grade Van Eck interceptor will be able to receive a useful signal.

Faraday rooms are standard issue in facilities that work with materials or devices sensitive to static discharge or electromagnetic radiation. If your company has a server room on-site, chances are it’s protected from lightning by a Faraday cage. The walls and ceiling are overlapping sheets of aluminum, iron, or copper, with the seams welded and sealed with EM-resistant gaskets. The whole thing is earthed, sending any signal that hits the wall directly into the ground. You can get a Faraday room built for you for the price of a low-end luxury car.

You can also build one yourself. Copper mesh is probably the most effective material for the price—about $8 per square foot. You’ll want several layers of mesh, each with a different opening radius to block as many different wavelengths as possible. The good news is that by the time you’re done building your Faraday cage, not only will your computer be fully protected, you won’t have any money left to steal. It’s a win-win!