Hillary Clinton is a skeptic of bitcoin, believing that widespread use might weaken existing currencies such as the dollar and destabilize countries large and small.
During a panel discussion at the Bloomberg New Economy Forum in Singapore on Friday, the former Democratic presidential candidate and Secretary of State delivered the remarks via webcast.
What appears to be a very exciting and rather unusual initiative to practically mine new coins in order to trade with them has the potential to undermine currencies, to undermine the function of the dollar as the reserve currency, to destabilize states," she added.
Clinton's remarks come as countries try to figure out how to regulate and utilize cryptocurrency.
China has outlawed the usage of cryptocurrencies for personal gain, as well as all cryptocurrency-related corporate activity.
Crypto-trading taxes will be harder under the newly passed $1 trillion US infrastructure plan.
In the meantime, some poor countries are adopting cryptocurrency.
In September, El Salvador made bitcoin legal tender in the hopes of improving its economy, and Zimbabwe is considering doing the same.
Amazon, Cargill, CVS, IBM, Seagate, and Visa are among the world's largest firms that have already adopted blockchain, the technology that underpins bitcoin.
Elon Musk, Richard Branson, and Jack Dorsey, as well as Miami Mayor Francis Suarez and incoming New York Mayor Eric Adams, have all expressed support for bitcoin and its widespread adoption.
Meanwhile, a new analysis by Chainalysis found that North America has become the world's biggest victim of ransomware attacks, paying $131 million in bitcoin to criminals in only one year, despite the rapid surge of cryptocurrency adoption.
According to the survey, the majority of crypto-based attacks were linked to cybercriminal gangs operating in Russia.
Economic laws specialist John Reed Stark, who spent 11 years as the chief of the SEC's Office of Internet Enforcement, told Insider that Clinton's reservations about crypto were "on the money."
"Investing in cryptocurrencies violates every key investor protection guideline," Stark told Insider.
"Bitcoin and other cryptocurrencies are traded on platforms that lack the same level of security as established exchanges."
During the session, Clinton also discussed cybersecurity in relation to foreign disinformation efforts and cyberwarfare, which continue to represent a threat to the United States and other Western countries.