FILE - In this April 21, 2009, photo, then-Lt. General Keith Alexander, who was then-director of the National Security Agency, speaks at the RSA Conference in San Francisco. Without warning, the electricity goes out, leaving you and your family in the dark for days, perhaps weeks. Or the gates of a dam holding back millions of gallons of water open suddenly and flood towns below. Or pipes in a chemical plant rupture, releasing deadly gas. Any one, or all, of these nightmare scenarios could be invisibly set in motion by hackers, terrorist groups or foreign governments with the motivation and technical know-how. Alexander, head of U.S. Cyber Command, has rated the country's preparedness for a major cyberattack as poor, a 3 on a scale of 1 to 10. (AP Photo/Jeff Chiu)