The anonymity that make bitcoin and cryptocurrencies like it so alluring is a large part of what makes them dangerous.
Not just to ransomware victims who find themselves forced to pay hackers in untraceable digital cash, but to investors sinking their savings into a currency that doesn't exist outside cyberspace and to government regulators seeking to preserve financial stability.
Since there's no way to trace transactions in cryptocurrency, there's no mechanism for recovery once it changes hands. And on top of that, there are the wild swings in value: Bitcoin lost nearly half its value, dropping 42 percent to $10,015, in just four weeks through the end of January as the level of concern and criticism from the government increased.
Those are among the issues that prompted corporate titans from Warren Buffett to JPMorgan's Jamie Dimon to turn up their noses at the prospect of doing business in cryptocurrency and spurred the Senate Banking Committee to schedule a hearing with Securities and Exchange Commission Chairman Jay Clayton and Commodity Futures Trading Commission Chairman J. Christopher Giancarlo.
"I want to make sure these are not used by bad guys, that they don't turn into old Swiss numbered bank accounts," Treasury Secretary Steve Mnuchin told the Banking Committee during testimony about the financial system's stability in late January. "In the U.S., if you're dealing with these cryptocurrencies and wallets and other things, you have the same Bank Secrecy Act, the same money laundering requirements as banks. We want to make sure that around the world, that exists."
It's also important to ensure that consumers tempted by run-ups in prices — bitcoin surged 14-fold last year — are aware of the risks, Mnuchin said. Cryptocurrencies are generated, or mined, when networked computers record and validate transactions in blockchain, a secure ledger accessible worldwide by multiple parties. Buying the equipment to handle mining, however, can be costly in itself.
"Experience tells us that while some market participants may make fortunes, the risks to all investors are high," Giancarlo and Clayton wrote in a column for the Wall Street Journal. "These markets are new, evolving and international. As such they require us to be nimble and forward-looking."
Both the SEC and the commodities-trading commission "are trying to sharply the curb the market in the United States for digital currencies," Jaret Seiberg, an analyst with Cowen Washington Research Group, said in a report.
While Seiberg doesn't expect a ban in the near future, "that could change long-term for national security reasons," he noted.
Indeed, trading in cryptocurrencies was banned last year by regulators in China who pointed to concerns about maintaining "economic and financial order," and JPMorgan's Dimon has said other countries are likely to do the same. Establishing a sovereign currency is one of the first actions governments undertake when they're formed, and none are likely to stand by while a competitive money supply they don't control grows large enough to become a threat, he said.
"In terms of cryptocurrencies, generally, I can say almost certainly that they will come to a bad ending," Buffett, the 87-year-old head of Berkshire Hathaway known as the Oracle of Omaha for his investing prowess, told CNBC in January. "We don't own any, we're not short any, and we'll never have a position in them."
Starbucks chairman Howard Schultz has a less dour view, though he doesn't believe bitcoin itself will be a currency in the future.
Eventually, however, blockchain will be used to create a legitimate currency, he told investors in January. To gain consumer trust, it will have to be legitimized in a brick-and-mortar company in which people have confidence, and the coffeehouse chain could be that place.
Starbucks, he hastened to add, isn't creating its own digital currency or even investing in one.
Still, "we are heading into a new age in which blockchain technology is going to provide a significant level of a digital currency that is going to have a consumer application," Schultz said. "And I believe that Starbucks is in a unique position to take advantage of that."