cybercommand center. >> how many cyberattacks do you see a day here? >> if you had to quantify, hundreds of thousands. >> and it gets worse, cyberattacks happening at lightning speed. so the nsa has to put up defenses just as fast. >> the fastest we've ever done that is ten minutes from start to finish. got the threat, put the defense up. >> ten minutes? >> ten minutes. >> incredible. >> the cyberintruders are getting faster, smarter. china, suspected in the largest theft of u.s. government personal information. russia, believed to be behind the hacking of white house e-mail. and now terrorists such as isis and al qaeda have learned how to disappear from u.s. electronic surveillance completely. >> is it true that terrorists or adversaries can go completely dark? >> absolutely. there is part of the world that's dark to us. in other words, we can't see. >> the term "to go dark" is what