Google has announced a major milestone in quantum technology with the introduction of its Willow chip. According to research published in the journal Science, this new chip has managed to reduce errors by approximately 40 times during the preparation of special quantum states required for complex computations. This development directly impacts the security of the Bitcoin network, as it addresses one of the most resource-intensive hurdles in building computers capable of breaking current encryption.

The Bitcoin Threat and Shor’s Algorithm

The security of Bitcoin wallets relies on the pair of private and public keys. While today's computers are unable to derive a private key from a public one, a sufficiently powerful quantum computer running Shor’s algorithm could theoretically achieve this. Google's progress focuses on the preparation of calculations, a stage often overlooked that consumes vast amounts of processing power.

Of particular concern is the vulnerability of older coins. Unlike modern methods that hide the public key, Bitcoins mined in the early years of the network have their keys exposed on the blockchain. Recent activity in dormant wallets from 2010 and 2011 may represent defensive moves by holders against future quantum attacks.

The "Cultivation" Method and Logical Qubits

The primary challenge in quantum computing remains the fragility of qubits, which are easily affected by external factors such as heat and vibration. Google's solution involves creating "logical qubits" by grouping physical qubits for error correction. These require so-called "magic states," which are continuously consumed during processing.

Using a method called "cultivation," the Willow chip:

  • Starts from a basic quantum state.
  • Checks for errors and discards problematic attempts.
  • Achieves 99.99% fidelity in the approved states.
  • Retains approximately 8 out of 100 attempts as "clean" states.

Although the technology is in its early stages and does not yet operate in real-time, the reduction in required hardware brings quantum supremacy one step closer to compromising the encryption protocols of Bitcoin and Ethereum.