Google's Willow Quantum Chip Reduces Error Rate in Magic State Preparation; Early Bitcoin Wallets at Risk from Quantum Computing

ChainCatcher reports that Google has announced its Willow quantum chip reduced the error rate in preparing special states (Magic States) required for quantum computation by approximately 40 times using a method called “Cultivation.” The related research was published this week in *Science* and could lower the hardware costs of future large-scale quantum computers, while drawing increased attention to the potential threat of breaking Bitcoin wallets. Magic States are critical resources needed to perform certain quantum operations, and their preparation consumes substantial hardware resources. Google’s experiment achieved a state fidelity of approximately 99.99%, but only about 8% of attempts passed screening. Researchers note that further scaling of the experiment and solutions for real-time operation and error correction are still required. In March, Google estimated that, under specific hardware assumptions, a future quantum computer might need fewer than 500,000 physical qubits to break the cryptographic protections used by Bitcoin and Ethereum wallets. For Bitcoin, some early wallets have had their public keys publicly exposed since mining, making them theoretically vulnerable to future quantum attacks; wallets whose public keys remain undisclosed may face different attack conditions. However, this breakthrough does not mean quantum computers are currently capable of breaking Bitcoin. Google’s prior cost estimates for such attacks already assumed an efficient Magic States preparation scheme; therefore, this result cannot be simply interpreted as a 40-fold reduction in the cost of breaking Bitcoin. The research remains in the stage of advancing quantum hardware and error-correction technologies, and the full device and engineering capabilities required for actual attacks have not yet been realized.