A new paper from Google Quantum AI has sharply reduced the estimated resources needed for a quantum attack on ECDLP-256, the elliptic curve problem that protects Bitcoin, Ethereum, and many other blockchain systems. Classical computers would still need an impractical amount of time to break it, but the study argues that a quantum computer running Shor’s algorithm could do so on a much shorter timescale in theory.
Resource estimates drop far below earlier assumptions
The research involved Google Quantum AI scientists, Ethereum Foundation researcher Justin Drake, and Stanford professor Dan Boneh. The paper describes two attack circuits. One would require fewer than 1,200 logical qubits and 90 million operations; the other would need fewer than 1,450 logical qubits and 70 million operations. In either case, the team estimates the attack could be carried out with under 500,000 physical qubits, down from earlier estimates of roughly 10 million qubits.
That does not mean a practical attack is ready today. It does mean the gap between theory and implementation may be narrowing faster than many in crypto had assumed, and the margin for delaying migration plans looks smaller than before.
Google withheld the full attack blueprint
Google did not release the detailed technical designs for the circuits. Instead, the team published a zero-knowledge proof that allows others to verify the correctness of the claim without exposing the underlying attack method. Ryan Babbush and Hartmut Neven of Google said the decision follows responsible disclosure norms commonly used in cybersecurity.
Google Quantum AI is the company’s advanced quantum computing research unit and has worked with academic partners across both theoretical and applied quantum algorithm design. The way this result was disclosed shows the firm considers the work security-sensitive, not just academically interesting.
More than 1.7 million BTC flagged in exposed-key wallet formats
The study warns that more than 1.7 million BTC are held in wallet formats where public keys have already been exposed. When additional script types are included, that figure rises to 2.3 million BTC. In a future quantum attack scenario, those coins would sit closer to the front line of risk.
The concern is not limited to Bitcoin. The paper says Ethereum, Solana, and other networks may face comparable exposure through certain smart contract implementations, staking platforms, and data storage methods. The issue touches core cryptographic assumptions across multiple chains.
The migration clock is now part of the debate
Google has set an internal 2029 deadline to complete its own move to post-quantum cryptography. That timeline reflects growing confidence inside the company that quantum threats could arrive earlier than once expected. The findings have also pushed several digital asset figures to call for immediate preparation.
Dragonfly Capital managing partner Haseeb Qureshi said the research is highly significant and argued that all blockchain networks should begin planning their transitions now. He said Google’s implementation of Shor’s algorithm looks much more efficient than earlier projections and that post-quantum readiness may be needed before the end of the decade.
Castle Island Ventures co-founder Nic Carter described the whitepaper as “very sobering.” In his view, new quantum papers are rapidly changing how urgent the issue looks, and the threat is no longer a distant hypothetical. He added that the Google Quantum AI paper might not even be the most concerning quantum paper released that day.