New Quantum Model Cuts Hardware Needed To Break Bitcoin Keys By 17 Times
A new estimate from quantum computing firm Alice & Bob suggests a future quantum computer with roughly 29,588 physical qubits, about 30,000, could break the cryptography protecting bitcoin wallets in around 62 minutes, a figure 17 times lower than the previous benchmark set by Google just eight months earlier.
How this compares to the last major estimate
Google’s own study, published in March 2026, put the qubit requirement for a similar attack below 500,000 physical qubits and modeled an attack taking roughly nine minutes, a dramatic drop from even earlier estimates that had run into the millions of qubits. Alice & Bob’s new figure, roughly 30,000 qubits for a 62-minute attack, represents another steep drop in the resources theoretically required, though the firm is careful to note the two studies rely on different hardware architectures and underlying assumptions, meaning they aren’t a perfectly apples-to-apples comparison.
Why the timing detail actually matters
Bitcoin’s average block confirmation time runs around 10 minutes, and a 62-minute theoretical attack window is, for now, too slow to reliably intercept and steal funds from a transaction before it confirms on-chain, a meaningful practical limitation even as the qubit-count side of the estimate keeps shrinking. Alice & Bob senior cryptanalyst Dahmun Goudarzi was direct about the open question this leaves: the team hasn’t yet calculated whether additional qubits could push that attack window under Bitcoin’s 10-minute block time, but said there’s no architectural floor preventing further estimates from converging closer to Google’s faster nine-minute figure.
The coins already most exposed
More than 6 million bitcoins currently sit at addresses whose public keys have already been exposed on-chain, typically from having made at least one outgoing transaction, which matters specifically because an attacker targeting those addresses would have considerably more time to work with than the tight window around a single unconfirmed transaction. Addresses that have never sent a transaction keep their public key hidden until the moment they do, offering meaningfully more protection under current quantum-threat models than addresses that have already revealed theirs.
What the researchers are actually recommending
Goudarzi framed the broader implication plainly: “Yes, it becomes of utmost importance that migration starts now,” pointing to the reality that replacing vulnerable cryptographic signatures across a fully decentralized network like Bitcoin’s is a slow, coordination-heavy process that could take years even once a clear migration path is agreed on. Alice & Bob expects the hardware improvements and falling resource requirements driving these successive estimates to meaningfully converge sometime in the early 2030s, a timeline that sounds distant until weighed against how long an actual network-wide cryptographic migration would realistically take to execute.
Quantum computing risk is a longer-horizon security question than most day-to-day crypto security advice covers; our complete Bitcoin security checklist focuses on the practical steps available today, while this kind of research is exactly why that checklist will likely need updates as quantum-resistant standards mature.
This article is for informational purposes only and does not constitute financial or technical advice. Figures described here reflect theoretical research estimates, not a confirmed present-day threat.