underestimate the cyber power the isolated nation of north korea can wield. people are always surprised because north korea is such a medieval society in many ways and yet have sophisticated high-tech capability to hack. the way they built it, also the way they at the same time are on the press pes of building an advanced nuclear capability. translator: the cyber war that started and no other country can attack north korea because there is no point. reporter: a former colonel in the north korea military who defected from kim jong-un came to hauo power. for years worked side-by-side with the hacking unit. notorious bureau 121. translator: only the very brightest students get to become hackers. they learn everything about the internet. then they work in the cyber research center, which is directly controlled by the