Bitcoin’s quantum threat is real, but far from an existential crisis, Galaxy says

Developers are already working to address quantum risks, and investors shouldn’t mistake a long-term challenge for an immediate threat, according to Galaxy Digital’s head of research Alex Thorn.

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What to know:

• Galaxy's Alex Thorn said the quantum threat to Bitcoin is real but limited today, affecting only certain exposed wallets and not current network security.
• Developers are already working on multiple solutions, including quantum-resistant addresses and phased upgrade proposals.
• Investors should view quantum risk as a long-term technical challenge, not a reason to avoid bitcoin today, Thorn said.

Fears that quantum computing could one day break Bitcoin’s cryptography have sparked a heated debate across the crypto industry.

But according to Alex Thorn, head of research at Galaxy Digital (GLXY), the narrative that Bitcoin is unprepared, or that investors should avoid exposure because of it, is overstated.

The risk itself is not imaginary. A sufficiently advanced quantum computer could, in theory, derive private keys from exposed public keys, allowing an attacker to forge signatures and steal funds. But Thorn argues that framing this as an imminent or uniquely Bitcoin-specific crisis misses critical context, both about the technology and about the work already underway to address it.

“The risk is real but recognized,” Thorn told CoinDesk in an interview. “And the people best positioned to solve it are actively working on it.”

Quantum computing is a fundamentally different approach to computation that uses the principles of quantum mechanics rather than classical physics. Instead of traditional bits that are either 0 or 1, quantum computers use “qubits,” which can exist in multiple states at once, a property known as superposition, allowing them to process many possibilities simultaneously.

Combined with another feature called entanglement, this enables quantum machines to solve certain complex problems far more efficiently than classical computers, particularly tasks like factoring large numbers that underpin modern encryption

Analysis from Project Eleven, a security firm focused on quantum risks in digital assets, suggests that roughly 7 million bitcoin BTC$70,426.40, worth about $470 billion at recent prices, could be vulnerable under a “long exposure” definition, meaning their public keys have already been revealed onchain. Other estimates vary widely depending on how exposure is defined.

Importantly, most bitcoin today is not immediately vulnerable. Funds are only at risk in scenarios where public keys are exposed onchain, either because users reused addresses, certain custodians employ operational shortcuts, or coins sit in older address formats. While some estimates suggest millions of BTC fall into these categories, they remain secure under current, publicly known quantum capabilities.

That distinction is central to Galaxy’s argument. The conversation has become polarized between those who dismiss quantum computing as decades away and those who warn of imminent danger. Thorn’s view lands in between. The probability of a future threat is meaningful enough to warrant action, but not so urgent that it outpaces Bitcoin’s ability to respond.

And that response is already underway.

A growing body of technical work is focused on making Bitcoin “quantum-resistant” over time. One of the most prominent efforts involves introducing new address types that rely on post-quantum cryptography. These would allow users to migrate funds away from potentially vulnerable formats, significantly reducing long-term exposure.

“There’s a lot more work being done than people realize,” Thorn said. “Developers are actively building pathways to upgrade the system.”

Other proposals tackle edge cases, such as dormant coins with permanently exposed public keys. One idea, sometimes referred to as an “hourglass” approach, would gradually restrict how such coins can be spent, mitigating systemic risk without outright confiscation or disruption.

More broadly, developers are exploring phased upgrade paths that would allow Bitcoin to adapt even under more extreme scenarios, such as a world where quantum systems can rapidly break existing cryptographic schemes. That could include changes to how transactions reveal public keys in the first place, limiting attack surfaces altogether.

While these efforts are complex, both technically and from a governance standpoint, Thorn emphasizes that Bitcoin’s open development model is a strength, not a weakness. The ecosystem has time, talent, and strong incentives to solve the problem well before it becomes critical.

Crucially, the number of actors capable of triggering a so-called “Q-day," when quantum computers can break modern cryptography, is still extremely limited. Even optimistic projections suggest only a small group of highly specialized researchers could achieve such a breakthrough in the foreseeable future.

Against that backdrop, Thorn views the growing wave of quantum-related fear, uncertainty, and doubt as disproportionate.

“Quantum computing is a powerful, potentially disruptive technology, but that doesn’t mean every risk is immediate or unmanageable,” he said.

For investors, the takeaway is straightforward. Quantum risk should be monitored, but not used as a blanket justification to avoid bitcoin exposure. The network has a track record of evolving in response to credible threats, and the groundwork for quantum resilience is already being laid.

"It’s not certain that quantum is an existential issue for bitcoin, but the chance that it is justifies concern,” Thorn said. “But what’s clear today is that Bitcoin developers are not ignoring it. Instead, many are actively working on it,” he added.

Read more: Cathie Wood's Ark Invest says quantum computing is a long-term risk for bitcoin, not an imminent threat

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