North Korea earns close to one billion dollars per year from illicit internet activity, primarily via illegal online gambling businesses.

Yoo Dong-ryol, head of the Korea Institute of Liberal Democracy and a former senior researcher at the Korean National Police University, made the claim at the South Korean military’s annual security conference in Seoul on Thursday.

Yoo said North Korea operates “tens of hubs in China and Southeast Asia” aimed at generating sorely needed foreign currency to prop up the isolated regime. Collectively, Yoo estimated these hubs earn around KRW 1t (US $864m) by “developing and selling illegal gambling programs, operating gambling sites using names of foreign nationals and stealing cyber money through hacking.”

Korea JoongAng Daily quoted Yoo saying illegal gambling software programs are sold for tens of millions of won, with further lucrative charges for upgrades. Yoo said the North hires local residents in other Asian countries to run the gambling sites, with the profits split “six to four or half-and-half.”