Earlier this month, Google announced a brand-new quantum chip dubbed Willow.
The 105-qubit chip — that’s double the qubit count of the tech giant’s preceding Sycamore chip — completed a computation in under five minutes that would take a modern supercomputer a “mind-boggling” 10 septillion years, the company said.
The news reignited a debate surrounding the security of blockchains, the distributed ledgers that run digital currencies like Bitcoin. Could a future quantum computer break the cryptocurrency’s encryption, allowing thieves to abscond with unfathomable sums?
As Fortune reports, researchers at the University of Kent found in a yet-to-be-peer-reviewed study that the risk is very real. In fact, just the downtime required to update the blockchain to protect itself from an encryption-breaking quantum computer could extend to 76 days — and the resulting losses would likely be staggering.
“Bringing your technology down… can be very, very costly, even if it’s on for a few minutes or a few hours,” coauthor and senior lecturer at the University of Kent Carlos Perez-Delgado told Fortune.
“If I had a large quantum computer right now, I could essentially take over all the Bitcoin,” he added. “By tomorrow, I could be reading everybody’s email and getting into everybody’s computer accounts, and that’s just the fact.”
But exactly how imminent this threat is remains highly debatable. In an update last week, AllianceBernstein analysts argued that Bitcoin contributors should “start preparing for the quantum future.”
However, “any practical threat to Bitcoin seems decades away,” the analysts wrote.
Researchers have similarly argued that it would take quantum computers with millions of qubits to break Bitcoin encryption in a single day.
Analysts have also found that SHA-256 encryption, which serves as the security measure protecting Bitcoin miners today, could eventually be cracked — albeit with quantum hardware that hasn’t even been dreamed up yet.
On a broader scale, apart from cracking cryptocurrencies, Google’s latest quantum chip also falls woefully short of doing anything actually useful as of right now.
“The particular calculation in question is to produce a random distribution,” German physicist and science communicator Sabine Hossenfelder tweeted in response to Google’s recent announcement. “The result of this calculation has no practical use.”
In short, while many agree that quantum computers could pose a growing threat to the cryptography behind Bitcoin, the cryptocurrency community could still have plenty of time to implement changes to protect the blockchain.
Which is easier said than done. As Fortune points out, Bitcoin’s decentralized nature could make pushing an encryption update an immense task.
But that doesn’t mean the cryptocurrency shouldn’t do it. In an October blog post, Vitalik Buterin, the cofounder of the prominent cryptocurrency Ethereum, argued that advancing quantum computing tech could have “consequences across the entire Ethereum roadmap.”
“The indisputable fact that nobody can argue is that when we do get there,” Perez-Delgado told Fortune, “our current securities, the cybersecurity systems — which includes everything from Bitcoin to email — will be in great danger.”
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