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.

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.

Those who are experts in the fields of surveillance, privacy, and technology say that there need to be two tracks: a policy track and a technology track. The technology track is encryption. It works and if you want privacy, then you should use it.

Snowden is almost preternaturally prepossessing and self-possessed. I think of a novelist whose dream character just walks into his or her head. It must have been like that with you and Snowden. But what if he'd been a graying guy with the same documents and far less intelligent things to say about them? In other words, how exactly did who he was make your movie and remake our world?

One of the things that I think is true is that encryption actually is able to secure our communications, that every individual can use encryption, and that it's accessible and in many cases free.

From a personal perspective, because I'm on a watchlist and went through years of trying to find out why, of having the government refuse to confirm or deny the very existence of such a list, it's so meaningful to have its existence brought into the open so that the public knows there is a watchlist, and so that the courts can now address the legality of it. I mean, the person who revealed this has done a huge public service and I'm personally thankful.

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.