Citizenfour Laura Poitras

By 2012, Poitras had begun work on the third film in her 9/11 trilogy (My Country, My Country (2006) and The Oath (2010)), which she intended to focus broadly on the topic of domestic surveillance for which she interviewed Assange, Greenwald, Binney, and Appelbaum.[18] She was first contacted by Snowden in January 2013 after he was unable to establish encrypted communications with Greenwald.[19][20] She flew to Hong Kong in late May 2013, where, over the course of eight days, she filmed Snowden in his hotel room[18] at the Mira Hotel in Hong Kong. Later, she traveled to Moscow where she filmed a second interview with Snowden conducted by Greenwald.

Production company Praxis Films was involved in the production of the documentary. The film was distributed by RADIUS TWC in the US,[21] BRITDOC Foundation and Artificial Eye in the UK[22] and Piffl Media in Germany. The broadcast rights for television were obtained by Channel 4 (United Kingdom), HBO Documentary Films (USA) and Norddeutscher Rundfunk (Germany).

The soundtrack consists of portions of the Nine Inch Nails album Ghosts I–IV, which was released under a Creative Commons license (BY-NC-SA) in 2008.

Security measures

Poitras took many security precautions related to the film, described by military writer Peter Maass among others.[23] She moved to Berlin, Germany[24] after being detained repeatedly at border controls when entering the US.[23] She edited the film in Germany after flying directly there from Hong Kong with the Snowden footage, to prevent the FBI from showing up with a search warrant for her hard drives. All the film footage is kept on encrypted drives with multiple levels of nested protection.[25] The computer she uses for reading sensitive documents is separated from the internet by an air gap. Greenwald credited her with a "complete expert level of understanding of how to do a story like this with total technical and operational safety". Maass called Poitras's security skills "particularly vital — and far from the journalistic norm — in an era of pervasive government spying", and quotes Snowden stating that "[i]n the wake of this year's disclosure, it should be clear that unencrypted journalist-source communication is unforgivably reckless."[23]

Producer Bonnefoy has also discussed the encrypted workflow used in making the film, adding "if we have a conversation that's particularly confidential, we'll move the electronics out of the room, or we'll just meet somewhere outside of the editing room, without our phones."[26]

The Film Society of Lincoln Center (which selects films for the New York Film Festival) reported[27] that Poitras changed the location of the initial screening for the NYFF's selection committee several times, in case someone was tracking her movements. The committee was shown a rough cut that had sensitive material redacted, and the NYFF "had to keep the movie's inclusion in the festival under wraps until mid-September" and it was "kept out of festival schedules and documents until we could talk about it openly". The last-minute inclusion in the festival's main slate was an unprecedented event for the NYFF,[28] and "tickets for both screenings sold out within just a few hours".[27]

The film's ending credits unusually[25] name several free software projects and security tools, without which "this film would not be possible". The programs named include Tor, Tails, Debian GNU/Linux, Off-the-Record Messaging, the GNU Privacy Guard, Truecrypt, and SecureDrop. In October 2014, the Electronic Frontier Foundation published an informational page about the software credited in the film,[29] and, in November 2015, Poitras was prominently featured in a Tor fund-raising campaign.[30]