We don't stand here alone, it's possible through the great organisations that support us. The disclosures that Edward Snowden revealed aren't only a threat to privacy but to democracy, when the most important decisions made affect all of us. Thank you to Edward Snowden. I share this with Glenn Greenwald and other journalists who are exposing truth.

In terms of sources coming forward, I really reject this idea of talking about one, two, three sources. There are many sources that have informed the reporting we've done and I think that Americans owe them a debt of gratitude for taking the risk they do.

Just consider the CIA and its effort to suppress the Senate's review of its torture program. Take in the fact that we live in a country that a) legalized torture and b) where no one was ever held to account for it, and now the government's internal look at what happened is being suppressed by the CIA. That's a frightening landscape to be in.

People are starting to understand that the devices we carry with us reveal our location, who we're talking to, and all kinds of other information.

I think one of the most shocking things is how little our elected officials knew about what the NSA was doing. Congress is learning from the reporting and that's staggering. Snowden and [former NSA employee] William Binney, who's also in the film as a whistleblower from a different generation, are technical people who understand the dangers.

So my first experience was that I had to do a reboot of my expectations. Like fantastic, great, he's young and charismatic and I was like wow, this is so disorienting, I have to reboot. In retrospect, I can see that it's really powerful that somebody [Snowden] so smart, so young, and with so much to lose risked so much.

There are people who are always going to try to engage in activity that is illegal and they're going to try to subvert surveillance. But everybody should not give up their liberties and rights to privacy because some people are going to [do that]. We shouldn't stop or limit our basic liberties because some people are going to engage in criminal activities.