One of the most frightening things, I think, is the capacity for retroactive searching, so you can go back in time and trace who someone is in contact with and where they've been.

The fact that the CIA knew that two of the 9/11 hijackers were entering the United States and didn't notify the FBI and that nobody lost their job is shocking. Instead, we occupied Iraq, which had nothing to do with 9/11. I mean, how did those choices get made?

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.

When the most important decisions are made in secret, we lose our ability to check the powers that control.

Certainly, when it comes to my profession as a journalist, that allows the government to trace what you're reporting, who you're talking to, and where you've been. So no matter whether or not I have a commitment to protect my sources, the government may still have information that might allow them to identify whom I'm talking to.

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.

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.

I don't speak Arabic - I know a little to get by, but that's all.

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.

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.