department of homeland security where he serves as deputy undersecretary of national protection, ellen nakoshima reports on national security issues for the "washington post." mr. ridinger, you talked about some of these threats and ellen gave an example of what could happen. but where do these threats come from? >> threats come -- let's say attacks. threats, events, attacks, they come from everywhere. one of the key points about cyber space is at distribution is actually very -- attribution is very difficult. back when i was a prosecutor that used to be sort of my business. about defense and not about attribution. but trying to find the trail of bread crumbs back to the ultimate source that's hacked these are very difficult. people are anonymous online. a hacker can go through multiple systems. so if he or she wants to break into a particular government computer they're going to first break into an university computer for example and then go through perhaps a couple of private computers, maybe even some individuals' home computer, before launching a attempt to intrude into and get access to tha