In her Senate confirmation hearing on Tuesday, Janet Yellen — the former Federal Reserve chair and U.S. President-elect Joe Biden’s pick for Secretary of the Treasury — said that “cryptocurrencies are of particular concern” for their role in facilitating criminal activity, and that she would keep a close eye on them in her new role.

In response to a question from Sen. Maggie Hassan of New Hampshire about how Yellen’s Treasury Department would work to rein in crypto-related crimes and terrorist financing in particular, Yellen said: “We need to make sure that our methods for dealing with these matters, with tech-terrorist financing, change along with changing technology.”

She continued: “Cryptocurrencies are of particular concern. I think many are used, at least in a transaction sense, mainly for illicit financing. And I think we really need to examine ways in which we can curtail their use, and make sure that anti-money laundering [sic] doesn’t occur through those channels.”

Yellen, who chaired the Federal Reserve from 2014 to 2018, has been critical of cryptocurrency — and bitcoin in particular — in the past. 

“I will just say outright I am not a fan,” Yellen said, of bitcoin at a fintech conference in 2018. And at a 2017 press event, Yellen said bitcoin is “not a stable store of value, and it doesn’t constitute legal tender.”

According to new data from the blockchain analytics firm Chainalysis, criminal transactions represented 2.1% of all crypto activity in 2019. That number fell to .34% in 2020, though Chainalysis has warned that this is a conservative estimate and that the number will likely grow to something more accurate as new scams are unearthed.

Those hoping for a lax U.S. Treasury when it comes to crypto matters may have to keep waiting.

This story originally appeared in Decrypt, a Forkast.News syndication partner, and appears here with additional updates by Forkast.News.