(Reuters) - The U.S. Treasury on Friday lifted economic sanctions against Tornado Cash, a firm that makes cryptocurrency transactions harder to track, which the Biden administration had accused of helping launder more than $7 billion for North Korean and other cyber hackers.

The Treasury Department's Office of Foreign Assets Control blacklisted Tornado Cash in 2022 after concluding it was helping launder the proceeds of cyber crimes, including more than $455 million stolen by Lazarus, a North Korean government-backed hacking group.

Six users of Tornado Cash - a cryptocurrency "mixer" that obscures the origins and recipients of transactions - had filed a lawsuit to challenge the sanctions with the financial backing of the Coinbase crypto exchange.

In November, a U.S. appeals court found that OFAC had overstepped its authority, but the sanctions remained in place.

In a statement, the Treasury said it had decided to repeal them after reviewing legal and policy issues raised by the use of sanctions within "evolving technology and legal environments".

Still, the Treasury Department said it remained concerned about North Korea's "state-sponsored hacking and money laundering campaign," through which it has stolen digital assets to finance government activities.

"Securing the digital asset industry from abuse by North Korea and other illicit actors is essential to establishing U.S. leadership and ensuring that the American people can benefit from financial innovation and inclusion," said Treasury Secretary Scott Bessent.

President Donald Trump has sought to broadly overhaul U.S. cryptocurrency policies and this month signed an executive order to establish a strategic reserve of cryptocurrencies. He also held a summit for industry leaders at the White House.

Two of the co-founders of Tornado Cash were charged in 2023 with facilitating more than $1 billion in money laundering, including for the Lazarus Group. One, Roman Storm, awaits trial and has denied engaging in criminal activity.

Last May, one of Tornado Cash's developers, Alexey Pertsev, was sentenced to five years and four months in prison in the Netherlands for money laundering.