Coinbase Research Warns Quantum Computing Threatens Bitcoin Security

• Coinbase research warns quantum computing could weaken Bitcoin’s core cryptography over the long term.
• About 32.7% of Bitcoin supply may be exposed due to public key reuse and legacy script types.
• Experts say quantum-resistant signature upgrades will be needed as computing capabilities advance.

Quantum computing is emerging as a possible long-term risk to Bitcoin’s cryptographic foundations, according to research commentary from a senior analyst at Coinbase. The assessment adds to a growing network of disclosures from financial institutions and technology experts examining how future advances in computing power could affect digital asset security models.

David Duong, head of global investment research at Coinbase, stated that recent progress in quantum computing could challenge the cryptographic mechanisms that secure Bitcoin. His comments referenced regulatory disclosures filed by BlackRock, which acknowledged similar risks in its amended prospectus for the iShares Bitcoin Trust ETF submitted to U.S. regulators on May 9, 2025.

In that filing, BlackRock stated that Bitcoin’s cryptographic infrastructure could become “flawed or ineffective” if quantum computing develops to a level capable of undermining current encryption standards. The firm noted that quantum computing remains in early stages, making its eventual impact difficult to quantify, but identified the technology as a material risk factor.

Algorithms and attack vectors under review

Duong highlighted that cryptographically relevant quantum computers (CRQCs) could eventually execute Shor’s and Grover’s algorithms, which target widely used cryptographic systems. In Bitcoin’s case, these algorithms could weaken two core components: the SHA-256 hashing function used in proof-of-work mining and the Elliptic Curve Digital Signature Algorithm (ECDSA) used to authorize transactions.

According to Duong, successful exploitation of these vulnerabilities could allow attackers to derive private keys from exposed public keys or gain efficiency advantages in mining. While quantum-enabled mining attacks were described as a lower-priority risk at present, signature-related threats were identified as more immediate in scope.

Share of supply exposed to long-range attacks

The research estimated that roughly 32.7% of Bitcoin’s circulating supply, approximately 6.51 million BTC, is susceptible to long-range attacks due t address reuse and script types that reveal public keys onchain. Duong identified Pay-to-Public-Key (P2PK), bare multisignature (P2MS), and Taproot (P2TR) outputs as examples where exposure exists.

He also noted that all Bitcoin outputs face short-range risk during the moment of spending, when public keys briefly appear in the mempool. These factors, the research said, support the need for eventual migration toward quantum-resistant signature schemes.

Broader context of quantum development

The warning comes in spite of ongoing advances in quantum research. In October 2025, Pierre-Luc Dallaire-Demers of Google stated that sufficiently advanced quantum systems could break Bitcoin’s cryptography within five years. Separately, Google has reported progress in quantum-related algorithms designed to support future practical applications, underscoring continued momentum in the field.

Duong added that while traditional financial systems may face greater disruption due to reliance on closed architectures, open blockchain protocols such as Bitcoin and Ethereum are already assessing cryptographic upgrades in response to these projected developments.