Bitcoin’s quantum computing threat has reached the upper echelons of finance.

And Sergio Ermotti, CEO of $5 trillion Swiss bank UBS, is the latest Wall Street leader to sound the alarm.

“The potential effect of quantum computing on the safety of [cryptocurrencies] still needs to be proved,” Ermotti told CNBC on Thursday at the World Economic Forum in Davos, Switzerland.

Ermotti joins a growing chorus that includes the likes of Ray Dalio, BlackRock, and Christopher Wood, the global head of equity strategy at Jefferies’ Financial Group.

Wood removed Bitcoin from his recommended long-term pension portfolio last week, citing the growing threat of quantum computers.

The store of value concept is clearly on less solid foundation.

—  Christopher Wood

Watching large financial institutions fret over quantum computing raises agonising questions: how secure is Bitcoin? How should developers protect the network? And when do they have to act?

Indeed, Bitcoin developers have been caught in a heated debate over how to address the threat of quantum computers, a theoretical but rapidly advancing technology that could break the encryption that undergirds the Bitcoin network.

Wood cited research from Chaincode Labs, which found that 20% to 50% of all Bitcoins could be stolen by thieves armed with quantum computers. That could amount to anywhere between $400 billion to $900 billion in Bitcoin.

‘Quietly concerned’

Crypto venture capitalist Nic Carter has been a vocal advocate of moving quickly to address the potential quantum threat.

He recently led a $20 million investment in Project Eleven, a startup attempting to address the threat that quantum computers pose to cryptocurrencies.

“In the world of institutional allocation, virtually everyone I have talked to is quietly concerned about Bitcoin,” Carter, a general partner at Castle Island Ventures, told DL News.

“I have yet to encounter a single individual who has carefully considered the risk and dismissed it entirely.”

But what is that risk, exactly?

Bitcoin uses the Elliptic Curve Digital Signature Algorithm, which ensures that only the owner of a private key can authorise a transaction. While current computers need trillions of years to derive private keys from exposed public keys, quantum computers could do so in hours or days.

Doing so would allow malicious actors to drain Bitcoin out of vulnerable wallets. Given the vast number of endangered coins, quantum computers could have a massive impact on the $1.7 trillion Bitcoin network.

Dalio, Ermotti, and Woods aside, most institutional concern hasn’t led to public warnings because the requisite analysis takes time and allocators don’t want to spook their clients, according to Carter.

“Many of them are in ‘wait and see’ mode to see if Bitcoin developers actually meaningfully respond to the threat,” he said.

But that patience is running out.

“I firmly believe that this year, if the Bitcoin developers don’t demonstrate any actual urgency, institutional allocators will start to make noise about it,” Carter told DL News.

They won’t publicly pressure development teams, however. Instead, they’ll act through capital deployment.

“They will simply, quietly downgrade and re-weight Bitcoin in their portfolios, or inform their clients they think there’s a 5% risk of Bitcoin going to 0 within 10 years,” Carter said.

Greed & Fear

Wood did just that in his long-running Greed & Fear newsletter last week, a copy of which was shared with DL News.

Wood said he believes Bitcoin developers will eventually act, burning vulnerable coins rather than letting hackers steal them.

While that could boost the value of the remaining coins, uncertainty over the quantum question has undermined Bitcoin’s claim to being a digital alternative to gold, the researcher noted.

“While GREED & fear does not believe that the quantum issue is about to hit the Bitcoin price dramatically in the near term, the store of value concept is clearly on less solid foundation from the standpoint of a long-term pension portfolio,” Wood wrote.

Previously, Wood had recommended that investors put 10% of their long-term pension portfolio in Bitcoin. Now, he suggests they put half that in gold, and the other half in gold mining stocks.

Gold has been on a tear, up 76% in the past year. The precious metal traded at $4,830 on Wednesday, according to Yahoo Finance.

Real or overblown?

To be sure, researchers disagree on when quantum computers will become powerful and stable enough to crack blockchains’ cryptography.

Pierre-Luc Dallaire-Demers, founder of Pauli Group, previously told DL News that quantum computers could crack Bitcoin’s encryption within four to five years.

“Google just keeps delivering milestones on schedule and that’s how the threat for Bitcoin will become increasingly more real,” Dallaire-Demers said.

Ethereum co-founder Vitalik Buterin sees the technology progressing even quicker. He warned in November that quantum computers could break Ethereum’s underlying security model before the next US presidential election in 2028.

Paulo Viana, another researcher, estimates eight years.

“Considering how complicated it is to transition to a quantum resistant option, eight years seems to be concerning,” he said.

‘Denial and complacency’

Carter’s frustration centres on the Bitcoin developer community.

“So far I have only seen denial and complacency from the developers,” Carter told DL News.

Indeed, many have brushed off the fear.

“My critique has been of people trying to trigger panic, using unrealistic short time-frames,” Bitcoin developer Adam Back wrote in December.

Bitcoin evangelist Michael Saylor has also been dismissive of the threat.

“I don’t worry about it,” he told Bloomberg News last year.

“Microsoft and Google market their quantum projects, but they would never sell a quantum computer that cracked cryptography as it would destroy their own companies.”

Perhaps one problem is that there’s no single solution. Bitcoin would need a package of half a dozen Bitcoin Improvement Proposals, or BIPs, to protect itself from quantum computing, Carter argued.

And even then, it could take years, given the notoriously sluggish process that BIPs have to go through to get approved.

Carter also believes that institutional quantum concerns are already affecting Bitcoin’s price.

“This is already resulting in a price headwind in my opinion, and I think it will only get worse this year, unless developers adopt a radically different outlook,” Carter said.

Pedro Solimano is a DL News markets correspondent based in Buenos Aires. Aleks Gilbert is a DL News DeFi correspondent based in New York City . Got a tip? Email them at psolimano@dlnews.com and aleks@dlnews.com.