As Digital Currency’s Popularity Rises, So Do Privacy Fears

Helping people without bank accounts “sounds very bleeding heart, but what if the end result is a surveilled bank account system?” says Rohan Grey, a professor of law at Willamette University who has worked on digital dollar proposals, including the one last spring. “Suddenly now you’re talking about building a monetary system where every transaction could be stored as data and create a robust social graph of the United States.”

Those concerns are as old as digital money. In 1994, my WIREd colleague Steven Levy profiled David Chaum, a cryptographer and inventor of a digital form of money called e-cash. His idea was that, instead of papers and coins, people would carry around digital tokens stored in dedicated devices that might look like a debit card or a key fob, or they could send them by email. (This was well before smartphones.) Chaum’s primary concern was how to keep those transactions secure and private using cryptographic controls. But at the time, a digital dollar issued by the US government wasn’t in the cards. “When I called a spokesperson for the Federal Reserve to ask about electronic cash, he laughed at me,” Levy wrote at the time. “It was as if I were inquiring about exchange rates with UFOs.”

That was before payments apps like Paypal, before Bitcoin, and before Facebook proposed Libra, now called Diem, which promises a form of private currency designed to remain within the walls of its vast digital fortress. It was before, in other words, central banks had much competition. In China, for example, private payment systems such as Alipay and WeChat Pay are near-ubiquitous. A government-issued digital yuan could allow competitors, such as traditional banks, to muscle their way into payments and would also potentially give the Chinese government more visibility into the nation’s economy.

Another impact of that competition is the dwindling use of physical cash. In Sweden, for example, officials view the e-krona as a way to ensure that money remains accessible to the public even in a world where physical cash is hard to come by. Otherwise, there might come a time when buying groceries, saving for retirement, or receiving a welfare check would depend on the strength of private financial networks. Even as it fades from view, public money also offers a kind of backstop in dire times. During the pandemic, fewer people are using cash, but the amount in circulation has actually increased as people stock up from ATMs. Cash is a safe haven—risk-free, so long as you pick a good hiding spot.

But would a digital currency be a replacement for cash? In a paper published last month titled “On the Possibility of a Cash-Like CBDC,” researchers at Sweden’s Riksbank argued that, no, it wasn’t really possible. The reason: privacy. Regardless of how a digital currency is designed, they wrote, someone would have to keep track of transactions to prevent what’s known as the double-spend problem—a digital equivalent of counterfeiting. In other words, digital transactions need to be tracked using some kind of ledger. And with that, it would be impossible to ensure absolute privacy, even with efforts to conceal details of transactions or the identities of the parties involved. With bits and bytes, there’s always the potential for a backdoor or a leak.

The WIRED Guide to Bitcoin

The cryptocurrency represents amazing technological advances. Bitcoin has a way to go before it’s a a true replacement for, or even adjunct to, the global financial system.

In theory, it would be possible for people to transact without leaving a trace, using forms of secure hardware, on which people could load their digital dollars and transact without connecting back to any centralized system. But current forms of secure hardware aren’t fault-proof and raise security concerns, explains Neha Narula, director of the Digital Currency Initiative at MIT, whose research team is working with the Federal Reserve in Boston to develop digital dollar prototypes. Privacy should be a top priority for any payment system, but setting sights on perfection can set up false expectations. “We’re approaching it as digital cash. But that doesn’t mean we’re trying to get beyond cash or replace cash,” she says.

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