While Researchers Say Bitcoin Has Time on Quantum Security, Not Everyone Agrees

A new report from Coinshares argues that quantum computing poses a manageable, long-term risk to Bitcoin, but a pointed rebuttal from a post-quantum security advocate says that confidence may be misplaced.

Post-Quantum Security Debate Heats up After Coinshares’ Bitcoin Report

The Coinshares report, titled “Quantum Vulnerability in Bitcoin: A Manageable Risk,” contends that while future quantum computers could theoretically undermine parts of Bitcoin’s cryptography, the practical danger remains distant and limited in scope.

Bitcoin.com News reported Sunday on Coinshares’ view, noting that the chief area of concern centers on Bitcoin’s elliptic-curve signature schemes, which could be weakened by Shor’s algorithm if sufficiently powerful quantum machines emerge. However, the firm emphasizes that such machines would require millions of fault-tolerant logical qubits—orders of magnitude beyond current capabilities.

Coinshares further argues that exposure is largely confined to legacy Pay-to-Public-Key (P2PK) addresses, which account for roughly 1.6 million BTC, or about 8% of total supply. Of that amount, only about 10,200 BTC sits in transaction sizes large enough to cause short-term market disruption if compromised suddenly, the report says.

More modern address formats, including Pay-to-Public-Key-Hash (P2PKH) and Pay-to-Script-Hash (P2SH), conceal public keys until funds are spent, significantly reducing quantum exposure. Coinshares also stresses that quantum computing cannot alter Bitcoin’s 21-million supply cap or bypass proof-of-work.

The firm cautions against aggressive interventions such as premature protocol forks or proposals to burn potentially vulnerable coins, arguing that such moves could undermine Bitcoin’s neutrality, decentralization, and property rights.

Instead, Coinshares suggests that gradual upgrades, including post-quantum signature schemes introduced via soft forks, would allow the network to adapt defensively over time. The report also contains several quotes from individuals in the industry, including Ledger CTO Charles Guillemet and Blockstream‘s Adam Back.

Is Bitcoin’s Quantum Risk a Growing Blind Spot?

The measured outlook from the latest Coinshares report has drawn criticism from Alex Pruden, the CEO of Project Eleven, who says the industry is underestimating both the pace of quantum progress and the scale of Bitcoin’s exposure. Alongside this, Nic Carter, who has been warning about quantum risk relentlessly, shared Pruden’s X thread and said:

“As much as I respect Chris and his work at Coinshares, he’s wrong on this one.”

In the X thread, Pruden argues that quantum timelines are compressing faster than commonly assumed and that the security community is increasingly treating post-quantum migration as urgent, not theoretical. The Project Eleven executive insists:

“Betting the security of trillions of dollars in assets on ‘it’ll be slow’ is reckless.”

Pruden points to recent research from Google showing that the number of qubits required to break widely used encryption schemes may be far lower than previously believed. He also cites government mandates requiring critical infrastructure to migrate to post-quantum cryptography by 2030 as evidence that threat models are shifting.

He disputes Coinshares’ claim that exposure is limited to legacy P2PK addresses, arguing that any Bitcoin address that has previously revealed a public key—including many large wallets—could be vulnerable to a sufficiently advanced quantum attack.

Pruden further criticizes what he characterizes as overreliance on selective expert opinions, warning that dismissing quantum risk because timelines remain uncertain could leave digital-asset networks scrambling when migration becomes unavoidable.

Ethan Heilman: Uncertainty, Not Imminence, Is the Real Quantum Risk

Alongside this, computer science researcher and software engineer Ethan Heilman contends that even if quantum computing presents no near-term danger to Bitcoin, the ecosystem should still approach the issue with urgency, given that defensive upgrades require years to design, implement, and gain broad adoption.

He emphasizes that timelines for cryptographically relevant quantum computers (CRQCs) remain deeply uncertain, and that low-probability, high-impact scenarios cannot be dismissed. Using hypothetical figures, Heilman explains in a brief X thread responding to Pruden that even a modest chance of a CRQC arriving earlier than expected becomes consequential once the multi-year effort required to develop a protocol solution—and the additional time needed for wallets and users to migrate—is taken into account.

Heilman’s central argument is that “far off” is an imprecise and often misleading phrase—some interpret it as five years, others as 30—and that the uncertainty itself is the true source of risk. Because adoption proceeds slowly and cautiously by necessity, Heilman argues that the prudent course is to begin steady, intentional progress now, reducing tail risks well before they evolve into pressing concerns.

Also read: Quantum Doomsday Clock Predicts Bitcoin’s Downfall by 2028

At the heart of the disagreement is not whether quantum computers will eventually threaten Bitcoin, but how soon networks must begin preparing—and how disruptive that preparation may be. Coinshares sees ample time for orderly upgrades, while Project Eleven argues that even a decade-long window is narrow given the complexity of migrating millions of keys in a decentralized system.

For now, the debate highlights a growing fault line in crypto security: whether Bitcoin’s resilience lies in patient evolution or early, coordinated action against threats that remain just beyond the horizon.

FAQ 🕰️

• Is quantum computing an immediate threat to Bitcoin?

No, most researchers agree that practical quantum attacks are not imminent, but timelines remain uncertain.

• Which Bitcoin addresses are most vulnerable to quantum attacks?

Legacy addresses and those that have already exposed public keys face higher theoretical risk.

• Can Bitcoin upgrade to resist quantum attacks?

Yes, post-quantum signature schemes could be introduced through future protocol upgrades.

• Why is there disagreement among experts?

The debate centers on how fast quantum capabilities may advance and how complex migration would be.