Alice & Bob: 30,000 qubits could break bitcoin in an hour

Quantum computing firm Alice & Bob estimates that a future machine with about 30,000 physical qubits (~29,588) could crack the cryptography protecting bitcoin wallets in roughly 62 minutes — about 17 times less hardware than Google's March estimate of under 500,000 qubits. The findings remain theoretical and rest on a different hardware design, but they suggest the computing power needed to threaten bitcoin could be smaller than previously thought.

An attack that fast would still be slower than bitcoin's 10-minute block time, making it too slow to reliably steal funds from pending transactions — but more than 6 million bitcoin sit at addresses with exposed public keys, where an attacker could take time to work backwards from a public key to the private one. Senior cryptanalyst Dahmun Goudarzi said "there is no architectural floor" and urged bitcoin developers to start migrating to quantum-resistant security now, warning that upgrades could take years as threatening hardware advances toward the early 2030s. Read the report.