How Laura Poitras Finds the Truth

Pasted on the wall next to the locked steel door that seals Laura Poitras’s studio from visitors and intruders is a black poster depicting a PGP key that the filmmaker has used in the past to receive encrypted messages. It makes sense that this key—a sort of invitation to send her a secret message—is the only identifiable sign that Poitras edits her movies in this building; she did, after all, once receive what is likely the most famous encrypted message of the 21st century, from Edward Snowden, who was the subject of her 2015 documentary, Citizenfour.