marc rogers is principal security researcher at cloudflare, and, joining us again, dmitri alperovitch, co- founder and chief technology officer at crowdstrike. dmitri alperovitch, you came on the program last week and made the case that the president was correct and that the f.b.i. was correct and this was definitely, definitely north korea. why so certain? remind people why are we so certain of that? >> i can't speak for the f.b.i. or u.s. government who are very certain but i can speak for crowdstrike who has done independent analysis and we have tracked it to a group active since 2006, primarily south korea, u.s. forces korea are looking for military planning, exercises observe the peninsula, things of natural concern and importance to north korea. we've seen them engage in destructive attacks like the sony attacks in colluding use of same infrastructure, some i.p. addresses used in the attack on sony were used in some of the past attacks and part of the malware, the code used in sewny, has been shared across some of the previous attacks, so we've seen them attack south korea in 20

marc one last consideration with you politically, end of the year happy new year to you both. be well. >>> tomorrow is 2015 which is just before 2016 so we'll have lots to talk about. >> roger ebert's" the new cnn film. we sit down with the director who gives us an inside look at ebert's life. >>> the critically acclaimed cnn film "life itself" makes its global tv debut here on cnn this sunday night. it dives into film critic roger ebert's life his relationships and his fight against cancer. john berman sat down with the director steve james starting with the discussion of ebert's inspiring love story with his wife, chaz. >> so it's about a man, in this movie, but also about to me at least a couple of relationships, a couple of amazing relationships. there's this love story with chaz. >> yes. >> which is just beautiful. >> yes. >> she is the love of my life. she saved me from the fate of living out my life alone, which is where i seem to be heading. >> to be able to witness that up close was to see the depth of that relationship was astounding and the love and the sort of connection that they had. i mean that was, you know i can't think of a more inspiring relationship and for me a