Google’s latest quantum computing development has reportedly cut certain error rates by a factor of 40 and achieved 99.9% accuracy, bringing renewed attention to the potential long-term threat quantum technology could pose to Bitcoin’s cryptographic defenses. However, the breakthrough focuses on reducing computational errors, and its effectiveness at a much larger scale has yet to be demonstrated.

The results do not indicate that Bitcoin faces an immediate quantum attack. Instead, they suggest that researchers are making progress on some of the technical challenges that have constrained quantum computing. Although the gap between current systems and more powerful machines may be narrowing, significant engineering hurdles remain.

Google’s research examines magic states, specialized resources required for certain quantum computing operations. The primary report estimates that producing these states can account for around 95% of a quantum computer’s processing capacity. Improving their generation and reliability could remove a major bottleneck in developing larger and more capable quantum systems.

Quantum error correction is a fundamental requirement for building fault-tolerant computers capable of performing complex calculations reliably. However, threatening Bitcoin’s cryptography would require several demanding capabilities to converge, including sufficient computing power and the ability to execute calculations accurately within a practical timeframe. The latest findings reinforce the importance of preparing for future quantum risks.

How Close Is Quantum Computing to Breaking Bitcoin?

A Google white paper published in March estimated that compromising Bitcoin’s cryptographic security could require between 1,200 and 1,450 logical qubits. These are error-corrected units used for reliable quantum calculations, rather than the raw physical qubits installed in a processor.

Google’s Willow quantum chip, announced in December 2024, contains 105 physical qubits. IBM has reported having 70 logical qubits, while QuEra has executed algorithms involving up to 96 logical qubits. IBM’s roadmap targets 200 logical qubits by 2029 and 2,000 by 2033, but these remain future objectives rather than demonstrated capabilities of current systems.

Separate estimates linked to Google and discussed in other reports suggest that fewer than 500,000 physical qubits might be sufficient under certain assumptions. This figure refers to physical qubits and should not be directly compared with the estimate of 1,200–1,450 logical qubits, since the two measurements describe different aspects of quantum computing capacity.

Another hypothetical scenario suggests that a sufficiently advanced quantum computer could derive a private key from an exposed public key in approximately nine minutes. This is a proposed future attack scenario, not an ability demonstrated by any existing quantum machine.

Bitcoin’s actual exposure would also depend on whether the public key associated with an address had been revealed. Google’s analysis examines quantum-related vulnerabilities across cryptocurrency systems, while protecting Bitcoin would require a technically sound migration plan and coordinated action among developers, users, exchanges and custodians.

Quantum Computing Presents a Long-Term Security Challenge for Bitcoin

The primary report estimates that roughly 6.26 million BTC are held in addresses considered vulnerable to potential quantum attacks. This risk is conditional on future machines becoming capable of deriving private keys from exposed public keys. Protecting those funds would require quantum-resistant security measures and a reliable process for moving assets to safer arrangements.

Jameson Lopp, co-founder and chief security officer of Casa, has estimated that a machine capable of breaking Bitcoin’s public-key cryptography could still be at least a decade away. Progress in quantum error correction highlights why the issue deserves attention, although it does not establish that such an attack is currently feasible.

At the time covered by the source report, Polymarket assigned a 1% probability to the relevant event occurring by the end of the year and an 11% probability by the end of 2027. These figures represent prediction-market expectations, not scientifically established timelines for when a quantum attack could become possible.

The broader challenge is ensuring that Bitcoin can transition to post-quantum security before a credible attack becomes feasible. Developing new cryptographic protections, testing their reliability and coordinating their adoption across the network could take considerable time. Beginning preparations early would give the ecosystem more opportunity to address technical and migration challenges.

For Bitcoin investors, Google’s latest result does not demonstrate an immediate security breach or independently establish a bearish trading signal for BTC. Its significance lies in the longer-term implications: quantum error correction is advancing, but building a reliable system capable of compromising Bitcoin’s cryptography would still require major progress in computational scale, fault tolerance and sustained performance that current quantum machines have not demonstrated.