Its rare that a hacker convention makes national news, but three MIT students caused a whole lot of controversy when they planned a presentation about security holes in Boston's subway system for DefCon in Las Vegas earlier this month. They were forced to cancel the talk at the last minute by a 10-day federal restraining order, requested by Boston's Massachusetts Bay Transit Authority (MBTA). On Tuesday, a judge denied motions by the MBTA to issue a preliminary injunction aimed at keeping the students quiet for a further five months. Now, in his most extensive interview to date, MIT subway hacker Zack Anderson talks with PM about what's wrong with the Charlie Card, what happened at DefCon, and what it's like to tango with the FBI and the MBTA.