Google has demonstrated a method for preparing “magic states” on its Willow quantum processor with about 40 times fewer errors, strengthening one component of the technology that could eventually challenge Bitcoin’s wallet cryptography.
Magic states are single-use resources needed for the non-Clifford operations that make universal quantum computing possible. Google’s cultivation method begins with a noisy state, checks it for errors and discards failed attempts.
Spending generally exposes a public key, while some newer payment formats keep it behind a hash until funds are moved. Older holdings with public keys exposed since mining would not receive that protection, and a recovery phrase stored offline would not prevent an attack based on blockchain data.
The experiment also transferred cultivated states from a distance-3 color code into a distance-5 surface code, showing that the states could move between two error-correction approaches on the same hardware. Google said the technique still must operate at larger scale, support real-time processing and preserve useful states as they enter stronger error-correcting systems.
The engineering advance arrives alongside renewed attention on dormant Bitcoin. Those movements do not establish that owners were responding to quantum risks; they could also reflect wallet changes, reorganized holdings or preparations to sell.
Under a specific set of hardware assumptions, Google previously estimated that a future superconducting quantum computer with fewer than 500,000 physical qubits could break the wallet cryptography used by Bitcoin and Ethereum. One modeled attack would last about nine minutes after a public key became available and require roughly 500,000 reliable magic states per second. The new experiment improves an input to that process, but the figures cannot be multiplied into a new attack-cost estimate because the earlier projection already assumed efficient magic-state production.