North Korea has started using nearly untraceable cryptocurrencies to convert stolen funds into cash and evade sanctions, according to an unpublished U.N. Panel of Experts report obtained by NK News. Experts estimate that hackers linked to the DPRK stole a total of $1.5 billion in cryptocurrency, some of which was exchanged for cash.

According to the report, “DPRK cyber actors have engaged in trading multiple forms of virtual currency, to include the use of several forms of alternative coins (‘altcoins’).” Altcoins are virtual currencies that are less popular than Bitcoins, but offer benefits like increased anonymity or faster transfers.