Analysts are reluctant to provide details about what types of cryptocurrency North Korea holds, which might give away investigation methods. Chainalysis said that Ether, a common cryptocurrency linked to the open-source blockchain platform Ethereum, was 58%, or about $230 million, of the $400 million stolen in 2021.
Chainalysis and TRM Labs use publicly available blockchain data to trace transactions and identify potential crimes. Such work has been cited by sanctions monitors, and according to public contracting records, both firms work with U.S. government agencies, including the IRS, FBI and DEA.
North Korea is under widespread international sanctions over its nuclear programme, giving it limited access to global trade or other sources of income and making crypto heists attractive, the investigators say.