US sanctions Tornado Cash over fears of aiding North Korean hackers

The United States on Monday imposed sanctions on Tornado Cash, a popular cryptocurrency service that allows users to mask their transactions, accusing it of helping hackers, including from North Korea, to launder proceeds from their cybercrimes.

The Lazarus Group, a well-known North Korean government-backed hacking group that has conducted numerous data breaches, both politically and sometimes financially motivated, has laundered at least $455m through Tornado Cash, the treasury said. The Lazarus Group is under US sanctions.

The United States and South Korea have said North Korea has mobilized thousands of hackers to steal funds including cryptocurrencies to finance its weapons programs. North Korea denies the allegations.

Tornado Cash was also used to launder about $100m after the hack of Horizon Bridge, a service operated by the Harmony blockchain, in June and as recently as last week in the $190m hack of crypto startup Nomad, the treasury said.

Despite requests for Tornado Cash to make changes, the criminal activity continued, the official said.

Reuters could not immediately reach Tornado Cash for comment.