The logo of Sony is displayed outside the Sony building at Ginza shopping district in Tokyo, Thursday, Dec. 18, 2014. A U.S. official says North Korea has been linked to the unprecedented act of cyberwarfare against Sony Pictures that exposed tens of thousands of sensitive documents and escalated to threats of terrorist attacks that ultimately drove the studio to cancel all release plans for the film at the heart of the hack, "The Interview."(AP Photo/Eugene Hoshiko)