U.S. Department of Homeland Security analysts work at the National Cybersecurity & Communications Integration Center (NCCIC) located just outside Washington in Arlington, Virginia September 24, 2010. U.S. national security planners are proposing that the 21st century's critical infrastructure -- power grids, communications, water utilities, financial networks -- be similarly shielded from cyber marauders and other foes. The ramparts would be virtual, their perimeters policed by the Pentagon and backed by digital weapons capable of circling the globe in milliseconds to knock out targets. To match Special Report USA-CYBERWAR/ REUTERS/Hyungwon Kang (UNITED STATES - Tags: CRIME LAW SCI TECH POLITICS)