U.S. expected to formally blame North Korea for Sony cyber attack

By Steve Holland and Aruna Viswanatha WASHINGTON (Reuters) - U.S. authorities were expected to announce on Friday that investigators had determined that North Korea was behind a devastating cyber attack against Sony Pictures, setting up a possible confrontation between Washington and Pyongyang. The probe into the hack found North Korea was involved and that there may also be a Chinese link, either through collaboration with Chinese actors or the use of Chinese servers to mask the origin of the a