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.
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.
Meanwhile, Bitcoin analyst Fred Krueger believes the emergence of a “quantum-resistant” version of the top crypto is inevitable.
“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.
