Fears that quantum computing could one day break Bitcoin’s cryptography have sparked heated debate in the crypto industry.
But according to Alex Thorn, head of research at Galaxy Digital (GLXY), the idea 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 a looming crisis or solely Bitcoin-specific misses critical context, both about the technology and the work already underway to address it.
“The risk is real but recognized,” Thorn told CoinDesk in an interview. “And the people best placed to solve it are actively working on it.” »
Quantum computing is a fundamentally different approach to computing that uses the principles of quantum mechanics rather than classical physics. Instead of traditional 0 or 1 bits, quantum computers use “qubits,” which can exist in multiple states at once, a property known as superposition, which allows them to process many possibilities simultaneously.
Combined with another feature called entanglement, this allows quantum machines to solve some complex problems much more efficiently than classical computers, particularly tasks such as factoring large numbers that underpin modern encryption.
Analysis from Project Eleven, a security firm focused on quantum risks related to digital assets, suggests that around 7 million bitcoins worth around $470 billion at recent prices, could be vulnerable under a “long exposure” definition, meaning their public keys have already been revealed on-chain. Other estimates vary considerably depending on how exposure is defined.
It is important to note that most bitcoins today are not immediately vulnerable. Funds are only at risk in scenarios where public keys are exposed on-chain, either because users have reused addresses, some custodians employ operational shortcuts, or because coins are in older address formats. Although some estimates suggest that millions of BTC fall into these categories, they remain secure thanks to current, publicly known quantum capabilities.
This distinction is at the heart of 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 falls somewhere between the two. The likelihood of a future threat is significant enough to warrant action, but not so urgent that it exceeds Bitcoin’s ability to respond.
And this response is already in progress.
A growing body of technical work aims to make Bitcoin “quantum-proof” over time. One of the most important efforts is to introduce new types of addresses based on post-quantum cryptography. This would allow users to migrate funds out of potentially vulnerable formats, significantly reducing long-term exposure.
“There’s a lot more work to be done than people think,” Thorn said. “Developers are actively working on upgrading the system. »
Other proposals address edge cases, such as dormant coins with permanently exposed public keys. One idea, sometimes referred to as the “hourglass” approach, would gradually limit how these coins can be spent, thereby mitigating systemic risk without confiscation or outright disruption.
More broadly, developers are exploring incremental upgrade paths that would allow Bitcoin to adapt even in more extreme scenarios, such as a world where quantum systems can quickly break existing cryptographic schemes. This could include changes to how transactions reveal public keys in the first place, thereby limiting attack surfaces altogether.
While these efforts are complex, both technically and from a governance perspective, Thorn emphasizes that Bitcoin’s open development model is a strength, not a weakness. The ecosystem has the time, talent, and strong incentives to solve the problem well before it becomes critical.
Importantly, the number of actors capable of triggering so-called “Q-day,” when quantum computers can break modern cryptography, is still extremely limited. Even the most optimistic projections suggest that only a small group of highly specialized researchers could achieve such a breakthrough in the near future.
In this context, Thorn sees the growing wave of quantum-related fear, uncertainty and doubt as disproportionate.
“Quantum computing is a powerful and potentially disruptive technology, but that does not mean all risks are immediate or unmanageable,” he said.
For investors, the conclusion is simple. Quantum risk should be monitored, but should not be used as a blanket justification for avoiding Bitcoin exposure. The network has a proven track record of scaling in response to credible threats, and the foundation for quantum resilience is already being laid.
“It is not certain that quantum is an existential problem for Bitcoin, but the likelihood that it is warrants concern,” Thorn said. “But what is clear today is that Bitcoin developers are not ignoring it. On the contrary, many are actively working on it,” he added.
Learn more: Cathie Wood’s Ark Invest Says Quantum Computing Is a Long-Term Risk for Bitcoin, Not an Imminent Threat
