What we're really debating is not security versus liberty, it's security versus surveillance. When we talk about electronic interception, the way that surveillance works is it preys on the weakness of protections that are being applied to all of our communications. The manner in which they're protected.

If an adversary didn't target our power plants but they did target the core routers, the backbones that tie our internet connections together, entire parts of the United States could be cut off. That would have a tremendous impact on us as a society and it would have a policy backlash.

America is a fundamentally good country. We have good people with good values who want to do the right thing. But the structures of power that exist are working to their own ends to extend their capability at the expense of the freedom of all publics.

You are not even aware of what is possible. The extent of their capabilities is horrifying. We can plant bugs in machines. Once you go on the network, I can identify your machine. You will never be safe whatever protections you put in place.

The only reason I do these interviews - I hate talking about myself, I hate doing this stuff - is because incredibly well-meaning people, whom I respect and trust, tell me that this will help bring about positive changes. It's not going to cause a sea change, but it will benefit the public.

We've seen a departure from the traditional work of the National Security Agency. They've become sort of the national hacking agency, the national surveillance agency. And they've lost sight of the fact that everything they do is supposed to make us more secure as a nation and a society.

We're now more than a year since my NSA revelations, and despite numerous hours of testimony before Congress, despite tons of off-the-record quotes from anonymous officials who have an ax to grind, not a single US official, not a single representative of the United States government, has ever pointed to a single case of individualized harm caused by these revelations. This, despite the fact that former NSA director Keith Alexander said this would cause grave and irrevocable harm to the nation.