When I was working in Japan, I created a system for ensuring that intelligence data was globally recoverable in the event of a disaster. I was not aware of the scope of mass surveillance. I came across some legal questions when I was creating it. My superiors pushed back and were like, "Well, how are we going to deal with this data?" And I was like, "I didn't even know it existed."

Much of what I saw in Geneva really disillusioned me about how my government functions and what its impact is in the world. I realised that I was part of something that was doing far more harm than good.

I had been looking for leaders, but I realized that leadership is about being the first to act.

Let's put it this way. The United States government has assembled a massive investigation team into me personally, into my work with the journalists, and they still have no idea what documents were provided to the journalist, what they have, what they don't have, because encryption works.

The internet is the most complex system that humans have ever invented. And with every internet enabled operation that we've seen so far, all of these offensive operations, we see knock on effects. We see unintended consequences.

[Bill] Binney designed ThinThread, an NSA program that used encryption to try to make mass surveillance less objectionable. It would still have been unlawful and unconstitutional.

It's important to remember when you start doing things like attacking hospitals through the internet, when you start attacking things like internet exchange points, when something goes wrong, people can die. If a hospital's infrastructure is affected, lifesaving equipment turns off.