As a journalist, Laura Poitras was the quiet mastermind behind the publication of Edward Snowden’s unprecedented NSA leak. As a filmmaker, her new movie Citizenfour makes clear she’s one of the most important directors working in documentary today. And when it comes to security technology, she’s a serious geek.

In the closing credits of Citizenfour, Poitras took the unusual step of adding an acknowledgment of the free software projects that made the film possible: The roll call includes the anonymity software Tor, the Tor-based operating system Tails, the anonymous upload system SecureDrop, GPG encryption, Off-The-Record (OTR) encrypted instant messaging, hard disk encryption software Truecrypt, and GNU Linux. All of that describes a technical setup that goes well beyond the precautions taken by most national security reporters, not to mention documentary filmmakers.

Poitras argues that without those technologies, neither her reporting on the Snowden leaks nor her film itself would have been possible. In an interview ahead of the October 24th opening of Citizenfour in theaters, she talked about the importance of those crypto tools, how to make a film in the shadow of the NSA, and a new era of high-level whistleblowing.

“These crypto tools let someone reveal information in a way that they can remain anonymous. That path has opened up.”

In January, Snowden contacted Poitras via anonymous email and began to describe the contents of the leak he planned to give her. Poitras says she quickly realized that “this was going to be a game-changer.” She asked her anonymous source to meet her for a more secure face-to-face conversation. But Snowden insisted that meeting in person was impossible, in part because he wished to remain anonymous even to Poitras herself. So they were left with fragile online communications. “If I wasn’t already up to speed with using encryption, this leak might never have happened,” she says. “It was necessary.”

Poitras filming in Utah. RADiUS-TWC

Poitras was already accustomed to encrypting her communications; she had been repeatedly stopped at the U.S. border and searched after the release of My Country, My Country, her 2006 film on the daily life of a family in Iraq, and later learned to use crypto tools when communicating with WikiLeaks' Julian Assange and privacy activist Jacob Appelbaum. When she realized the depth of Snowden's leaks, she went so far as to buy a new laptop—with cash—and to use it only with the Tails operating system. That free software is designed to leave no trace of your communications on your computer and to route all network data over the Tor anonymity network. Poitras says she used that Tails computer only to communicate with Snowden, and only in public places with Wifi connections—never her home or office.

Aside from her communications with Snowden, Poitras says she also kept all the film's footage on encrypted drives. Given that more than 30 people worked on the film, that's no simple organizational task. Poitras declined to share the full details of her security scheme for that content, but she says that “some of it is more deeply nested in terms of how it’s protected and who has access to it.” In fact, not even Citzenfour’s funders and distributors saw a full, unredacted version of the film until just days before its premiere at the New York Film Festival last Friday. Until then, she showed them versions that had black blocks covering portions of certain frames.

“No amount of violence can solve a math problem.”

Poitras’ caution is echoed in the movie’s narrative. In intimate scenes she recorded with Snowden in his Hong Kong hotel room—the core of her film—she shows him worrying that the VoIP deskphone in his room has been turned into a bug. He chides Glenn Greenwald for using a too-short password, dons a blanket over his head and laptop to enter his own passphrase (Snowden jokingly calls it his “magical mantel of power”) and freezes up when a fire alarm test interrupts their work, suspecting foul play. Still, Poitras says that none of that was meant to portray Snowden as paranoid. “I wouldn’t describe anything that Snowden recommends in that hotel room as paranoia,” she says. “When your adversary is the NSA, that’s not paranoid.”

But despite her dark assessment of the NSA’s reach, Poitras argues that Snowden's ability to stay out of the agency’s grasp shows the power of cryptography. She quotes the cypherpunk mantra that cryptography levels the playing field between the individual and the government; it represents a math problem that no amount of authoritarian force can solve. “I do think that so long as we can maintain the ability for crypto not to be backdoored, there’s a way for people to communicate securely,” she says.

“I have a lot of respect for the cypherpunk movement,” she adds. “The free software community should be supported more widely. I’m totally in solidarity with what they do.”

"There are people who have profound moral concerns about these policies. And that leads to whistleblowers."

Poitras, the recipient of Macarthur "genius" grant in 2012, argues we've entered a new era of whistleblowing, one in which insiders will increasingly come forward to leak evidence of corruption and injustice. But she cautions that technology is only a part of the shift. "It’s not just about the tools. It’s about people willing to risk their lives to expose information," she says.

Poitras points to a new generation of government insiders who she says feel betrayed by the permanent institutionalization under Obama of policies that they saw as emergency measures under Bush. "The growth of the surveillance state, the increased drone wars, Guantanamo, these are activities that the U.S. government is engaging in that people think the public has a right to know about, and that they’ll take risks to reveal," she says. "There are many, many whistleblowers and sources out there."

"One of the legacies of Snowden’s disclosures, perhaps, is breaking the model."

After years of shooting for Citizenfour, Poitras says she actually discovered she had the material for two films. She won't say exactly what the subject of this second film might be, but hints that much of her footage is of Julian Assange. She's also working on a gallery exhibit at the Whitney Museum in New York scheduled for 2016.

In the meantime, Poitras has helped to found the Intercept, an investigative online magazine launched with Glenn Greenwald, Jeremy Scahill and eBay billionaire Pierre Omidyar. In her film, she reveals that the Intercept already has a second source, one who's communicated with Jeremy Scahill via encrypted messages and given him secret information on a U.S. terrorist watchlist and drone programs.

Poitras refused to discuss that source. But she points to the Intercept as part of a new media movement that's bolder and less beholden to governments' requests that leaked information be filtered or redacted. No longer will sources need to leak their secrets to the New York Times, which held off on revealing Bush's warrantless wiretapping program for more than a year at the administration's request.

"We all know these stories of sources who take a risk to approach an institution and that institution doesn't publish the information," she says. "I think that the existence of the Intercept or WikiLeaks or other outlets that are willing to publish that information creates a different media landscape."

And should we expect to see more radical disclosures from those outlets? Poitras bristles at the word "radical."

"I don't think what we're doing is radical," she says. "I think it's radical to censor information because the government asks you to. That's radical."