Google’s latest breakthrough with its Willow quantum chip has intensified concerns about the security of Satoshi-era Bitcoin holdings. The chip significantly reduced errors by about 40-fold when preparing magic states, a critical resource for quantum calculations that could potentially crack Bitcoin wallets. While the experiment achieved high fidelity (99.99%) among the states that passed inspection, only 8% of preparation attempts succeeded, highlighting substantial scaling challenges ahead.
The findings underscore why older Bitcoin coins, whose public keys have been exposed for years, are particularly vulnerable. An attacker using Shor’s algorithm could theoretically reverse-engineer secret keys from public ones, allowing them to sign transactions as the owner. This risk is heightened for coins that have been inactive for decades, as seen with recent movements of 100.02 BTC from July 2010 and 553.59 BTC from wallets inactive since 2011-2014.
Quantum computers face significant hurdles, including the fragility of qubits and the need for constant production of magic states. Google’s cultivation method aims to streamline this process, but real-time operations and error correction remain areas needing further development. Earlier research suggested that a quantum computer with fewer than 500,000 physical qubits could break Bitcoin’s wallet cryptography, and Google’s latest work advances the engineering methods needed to sustain such an attack.
While the breakthrough does not immediately make a Bitcoin attack 40 times cheaper, it brings the threat closer to reality. The debate over quantum risks continues to grow, with some holders moving their coins in response to these concerns.