More than 2,000 radiologic detectors were deployed at US ports of entry following the attacks of 9/11. The nondescript roadside boxes can stand more than 14 feet tall and sniff out fissile material passing by in trucks, cars or shipping containers. But are those radiologic detectors as good at fending off cyber attacks? In our final segment, we speak with Dr. Rico Chandra, the CEO and co-founder of Arktis, which makes radiologic detectors, about efforts to shore up this critical infrastructure against cyber attack and the steps his company is taking to harden their devices.