Research Cuts Bitcoin-Breaking Quantum Computer Estimate 20-Fold to 500,000 Qubits
Updated
Updated · blog.bitpanda.com · Jul 21
Research Cuts Bitcoin-Breaking Quantum Computer Estimate 20-Fold to 500,000 Qubits
3 articles · Updated · blog.bitpanda.com · Jul 21
Summary
A new paper says a quantum computer capable of breaking Bitcoin cryptography may need about 500,000 error-corrected qubits—roughly 20 times fewer than earlier estimates, bringing the engineering target closer.
That still leaves the threat beyond current hardware: the largest demonstrated quantum machines are around 1,000 qubits, and experts still broadly place a viable attack in the 2030s.
Bitcoin is not equally exposed today because unused addresses do not reveal the public-key data needed for this kind of attack; older address formats, including some long-dormant holdings, remain a harder problem.
NIST finalized post-quantum cryptography standards in 2024, and blockchains including QRL, Algorand and XRP Ledger have already deployed or tested them, while Bitcoin and Ethereum have active upgrade proposals.
For most crypto users, the nearer risk remains classical theft: Chainalysis said about $1.7 billion was stolen in 2023 through hacks, phishing and key compromises, not quantum attacks.
Are nation-states already harvesting our crypto data, waiting for a quantum computer to unlock it all?
To save Bitcoin from quantum theft, must the network freeze billions in dormant coins, betraying its core promise?
6.9 Million Bitcoin at Risk: How Google's 2026 Quantum Breakthrough Accelerates the Urgency for Crypto Security and Post-Quantum Migration
Overview
In March 2026, Google Quantum AI published a landmark whitepaper that created a new urgency for cryptocurrency security. The report highlights how quantum computing, especially through Shor's algorithm, poses a real threat to current cryptographic standards like ECDLP-256, which protect networks such as Bitcoin and Ethereum. The Taproot upgrade in Bitcoin, while improving privacy, also exposes public keys, making them potentially vulnerable to future quantum attacks. Despite growing awareness, no major quantum-specific security changes had been made to Bitcoin’s core by 2025. This situation underscores the need for immediate action to develop quantum-resistant solutions and protect digital assets.