LS: The population around the world is more or less completely left in the dark when it comes to espionage by means of electromagnetic radiation and seeing through walls from the outside by means of mobile stationary and air- or space-based systems. Are such things not only technically possible, but are rather common practice nowadays?

TD: Technically possible is an understatement. Yes, I’m certainly aware even from the time I was in NSA there were systems that would allow you to penetrate extraordinary types of surveillance that go far beyond what I call traditional, even in the electronic space, but when you’re talking about magnetic scanning systems yes, there’s a lot that can be detected. There are specialized vans that do that.

Is it persistent, meaning is it everywhere? No. This technology is still kind of expensive, but where it’s employed, yes I can effectively see through walls. It’s sort of [like] radar – you have radar, ground penetrating radar; this is the electromagnetic version of that that allows you to basically – I’m familiar with technology that basically when it’s directed it can scan for any and all electronic devices.

Let me give you one small example to illustrate what’s possible. When I used to live in England, you had to pay, when I used to fly in RC-135s [a large reconnaissance aircraft] – you had to pay [for a license] to listen to a radio [this was abolished in 1971] and watch television. They used to have vans that would drive around to detect whether or not the [TV] antenna was active, meaning it was actively receiving a signal, not transmitting actively receiving a signal and it could do geo-location. … if it detected an antenna that was actively receiving a signal then they would triangulate, they would find out did you have a license and if you did not have a license then you would be fined. Well take that to a much larger level, where I was aware in the military about equipment that would basically scan systems and it would pick up all, every signature it could find, both passive and active. So, yes it’s not just possible, it’s actual.