Google's Quantum AI team has dramatically lowered the bar for breaking Bitcoin's ECDSA cryptography, estimating that a future quantum computer could succeed with under 500,000 physical qubits-far fewer than the millions previously thought.

Their optimized Shor's algorithm models show a potential double-spend attack completing in about 9 minutes, outpacing Bitcoin's typical 10-minute block time and achieving a 41% success rate in simulations, particularly against addresses with exposed public keys.

This development highlights risks to roughly 25% of BTC holdings in legacy addresses vulnerable to such attacks once a cryptographically relevant quantum machine emerges.

Google has set 2029 as a critical deadline for migrating to post-quantum cryptography to safeguard systems, urging Bitcoin developers to accelerate upgrades before the threat materializes.

The research underscores that while quantum computers remain years away from this capability, proactive protocol changes like quantum-resistant signatures are now more urgent than ever.
https://www.mexc.com/cs-CZ/news/988874