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 all my work, I'm interested in trying to understand the human consequences of government policies.

We're definitely in an era where the government wants to keep more secrets and it wants to come after anyone who's exposing those secrets and in many cases exposing government illegality. They're coming after the journalists and they're coming after the whistleblowers. It's not a good sign if the government is expending much energy trying to find out who journalists are talking to.

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.

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 was in correspondence with an anonymous source for about five months and in the process of developing a dialogue you build ideas, of course, about who that person might be. My idea was that he was in his late forties, early fifties. I figured he must be Internet generation because he was super tech-savvy, but I thought that, given the level of access and information he was able to discuss, he had to be older.

It's not everyday that a whistleblower is actually willing to be identified.