Watch 123Movies. DEFCON is the world's largest hacking conference, held in Las Vegas, Nevada. In 2012 it was held for the 20th time. The conference has strict no-filming policies, but for DEFCON 20, a documentary crew was allowed full access to the event. The film follows the four days of the conference, the events and people (attendees and staff), and covers history and philosophy behind DEFCON's success and unique experience.