David Duong, Head of Institutional Research at major U.S. cryptocurrency exchange Coinbase, warned on January 5 that advances in quantum computing could become a structural threat to Bitcoin’s long-term security.

$IonQ ? Coinbase warns: ~33% of Bitcoin supply vulnerable to quantum attacks.
The post-quantum transition is no longer theoretical it’s becoming an institutional priority.

Quantum-safe solutions from @IonQ_Inc and @IDQuantique are the infrastructure of tomorrow’s security.… pic.twitter.com/M7NWBWjU2H

— TechInnovation (@TechInnovationz) January 6, 2026

According to Duong’s analysis, approximately 6.51 million BTC , nearly one-third of the circulating Bitcoin supply , could be vulnerable to future quantum attacks. The risk stems from Bitcoin addresses where public keys are already exposed on-chain, particularly in cases involving address reuse or legacy script types.

Concerns Over Bitcoin’s Signature Security

Bitcoin’s security model relies primarily on the Elliptic Curve Digital Signature Algorithm (ECDSA) for transaction authentication and the SHA-256 hash function for mining. Duong cautioned that sufficiently powerful quantum computers could theoretically derive private keys from exposed public keys, allowing attackers to drain funds from vulnerable addresses.

While quantum computing remains largely experimental, Duong emphasized that the threat is transitioning from a purely theoretical concern to a credible long-term structural risk. He noted that markets may not be adequately pricing in this possibility, even though the implications for Bitcoin’s future valuation could be significant.

Duong argued that signature security poses a more immediate concern than quantum-powered mining attacks, which remain constrained by current scalability limitations. If attackers can identify exposed public keys, they could impersonate legitimate owners and move funds without authorization.

As a result, investors may need to reassess wallet management practices, particularly avoiding address reuse and migrating funds to more secure address formats.

Market Awareness Grows as Institutions Flag Quantum Risk

Awareness of quantum-related risks is increasing among institutional investors. In May 2025, asset management giant BlackRock updated the prospectus for its spot Bitcoin ETF, the iShares Bitcoin Trust, explicitly listing quantum computing as a potential risk factor.

Duong observed that the growing adoption of Bitcoin ETFs has accelerated institutional participation, bringing greater scrutiny to long-term systemic risks such as quantum computing.

Transitioning Bitcoin to quantum-resistant cryptographic standards would require broad coordination across the ecosystem, including wallet providers, exchanges, miners, custodians, and developers. Achieving consensus and executing such a transition would be a complex and time-consuming process.

Duong stressed that preparations must begin well before quantum computers are capable of breaking cryptographic protections, not after the threat becomes imminent.

Although the likelihood of a near-term quantum attack remains low, the potential value of assets at risk could reach hundreds of billions of USD, making proactive planning essential for Bitcoin’s long-term resilience.