"In this March 22, 2007 file photo, U.S. Assistant Secretary of State Christopher Hill, right, walks through a hotel lobby with Victor Cha, the U.S. National Security Council's director for Asian Affairs, before heading to six-party talks on North Korea's nuclear program, in Beijing. Cha, who served as Asia policy director in the George W. Bush White House, said despite the long history of censuring North Korea over its weapons development, there's no diplomatic play book to follow in a case like the destructive hacking attack against Sony Pictures. ""On the nuclear and missile side we have established a pattern of interactions between states on how to respond, but in the cyber world there's no rules right now,"" he said. (AP Photo/Greg Baker, File)"
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