Director Alex Gibney called for a national debate on cyber warfare at a screening of “Zero Hour,” his documentary on the details of a cyberattack on Iran's nuclear program.

The Harvard Kennedy School’s Belfer Center for Science and International Affairs hosted the screening Friday. The documentary is partly based on research on clandestine warfare by David E. Sanger ’82, chief Washington correspondent for The New York Times and a former Crimson editor, and features interviews with Belfer affiliates such as Executive Director for Research Gary Samore and Rolf Mowatt-Larssen, a senior research fellow at the Kennedy School.

“Zero Days” lays out the events leading to the cyber attack on Iran’s nuclear infrastructure in 2009. The U.S. military, with aid from its Israeli counterparts, developed computer malware to impair Iran’s nuclear program, according to the documentary. The malware ended up spreading beyond the nuclear facility.

Gibney began his research for the film based on his interest in cyber conflict. As he investigated further into the attack, however, he became more concerned with the political ramifications of the documentary.

“There was a whole world of threat that was all around us that I hadn’t at all appreciated,” he said.

The screening was followed by a panel with Gibney and Sanger, who is also an adjunct lecturer at the Kennedy School, that addressed issues the documentary details. Much of the panel focused on the potential danger of cyber warfare.

“Once cyber crosses into the realm of the physical, then it’s a physical attack, but it starts with cyber. And the idea of a cyber attack being able to take control of machines—that becomes a scary process,” Sanger said.

Gibney expressed his hope that the documentary would spark a national discussion about what he called the secrecy surrounding the cyber attack on Iran.

“I was hoping to provoke people to say, ‘Enough of the secrecy.’ The secrecy is putting us all at risk,” Gibney said.

Kilian M. Blum, a graduate student at the Fletcher School of Law and Diplomacy at Tufts who attended the event, said the movie not only focused on the use of cyber weaponry but also the politics involved in the conflict.

“I think the movie found a good balance between simplifying very complex affairs and still make it interesting even for a moderately informed audience,” Blum said. “It gave a broad overview on both the cyber side and the international relations side of the issue.”