Bitcoin’s cryptographic resilience is facing renewed questions after a Google researcher suggested that quantum computers may be capable of breaking its encryption far sooner than expected.
Craig Gidney, a leading quantum computing researcher at Google, published new findings indicating that the hardware requirements to break 2048-bit RSA encryption, a key mathematical element similar to that of Bitcoin, have dropped significantly.
Gidney pointed out that his earlier estimates placed the threshold at 20 million noisy qubits, but the new projection requires fewer than one million.
The reduced computational burden marks a significant leap in quantum capability, though it might take several days instead of a few hours.
The Google researcher attributes the advancement to more refined quantum algorithms and enhanced error correction techniques that reduce the number of physical qubits needed by encoding logical qubits more efficiently.
Bitcoin’s quantum computing frailties
The revelations arrive as concerns grow over the pace of quantum computing development. Last year, Google introduced its Willow chip, a next-generation quantum processor that many believe brought real-world threats to digital security closer than previously assumed.
In response, major financial institutions are updating their disclosures. For example, BlackRock recently flagged quantum computing as a material risk for its Bitcoin ETF product, IBIT.
According to the firm:
“If quantum computing technology is able to advance and significantly increase its capacity relative to the capacity of today’s leading quantum computers, it could potentially undermine the viability of many of the cryptographic algorithms used across the world’s information technology infrastructure, including the cryptographic algorithms used for digital assets like Bitcoin.”
This shift reflects growing awareness that technological breakthroughs could challenge Bitcoin’s foundational encryption earlier than anticipated.
Despite the concern, some experts believe the crypto sector still has time to adapt to the potential risks.
Today’s logical-qubit demos top out at dozens (e.g., Quantinuum’s 12 logical qubits). Gidney’s 1,000,000-qubit figure is about physical (noisy) qubits, not logical. We’re three orders of magnitude away in sheer qubit count, and need major error-rate breakthroughs.
Even the physical-qubit goal is likely 8–12 years out, and a true million-logical-qubit machine is decades away.
| Leading platform (universal gate-based) | Physical qubits | Notes |
|---|---|---|
| IBM “Condor” (superconducting) | 1,121 | First >1 k-qubit chip, still noisy |
| Atom Computing (neutral atoms) | >1,000 | Prototype announced in March 2025 |
| Google “Willow” (superconducting) | 105 | Record low error rates, crosses QEC “threshold” |
| Quantinuum H2 (trapped ions) | 56 | High-fidelity ion trap; Microsoft used it to build 12 logical qubits |
| D-Wave Advantage 2 (annealer) | 1,200 | Not a universal machine, can’t run Shor’s algorithm |
Meanwhile, Bitcoin analyst Fred Krueger believes the emergence of a “quantum-resistant” version of the top crypto is inevitable.
He anticipates a network split between a newly fortified Bitcoin and a legacy version, similar to how Ethereum split into ETH and Ethereum Classic.
He stated:
“Ulimately there will be a fork. ‘Quantum Resistant Bitcoin (QRB)’ and ‘Bitcoin Classic.’ The big money will recognize and push QRB. Some will fight it. Bitcoin Classic (BTC) will become the new Ethereum Classic.”
Still, if Bitcoin becomes vulnerable in eight years, the network will not have long to adopt a quantum-resistant upgrade.