Google Says Quantum Computers Could Break Bitcoin And Crypto Encryption In 10 Minutes

Google has published research showing that the encryption protecting Bitcoin and most other cryptocurrencies could be broken by a quantum computer using far less computing power than previously thought. Before reading further, SMBtech reminds readers that other infrastructure security (including that used by banks) would likely fall even quicker.

The tech giant’s Quantum AI division has outlined two new quantum circuits that could crack 256-bit elliptic curve cryptography – the backbone of blockchain security – using roughly 20 times fewer physical qubits than prior estimates suggested.

While the quantum computer powerful enough to execute such an attack does not yet exist, Google has set itself an internal deadline of 2029 to migrate its own systems to quantum-resistant encryption. The timeline signals the company views this as a near-term threat rather than a distant theoretical concern.

Fewer qubits, bigger problem

In a whitepaper released this week, Ryan Babbush, Director of Research for Quantum Algorithms at Google, and Hartmut Neven, VP of Engineering at Google Quantum AI, detailed two quantum circuits implementing Shor’s algorithm against the 256-bit elliptic curve discrete logarithm problem, known as ECDLP-256.

One circuit uses fewer than 1,200 logical qubits and 90 million Toffoli gates. The other uses fewer than 1,450 logical qubits and 70 million Toffoli gates.

The researchers estimate either circuit could be executed on a superconducting qubit machine with fewer than 500,000 physical qubits in a matter of minutes, based on hardware assumptions consistent with some of Google’s existing quantum processors.

That represents an approximately 20-fold reduction in the number of physical qubits required compared with previous estimates, and continues what Google describes as a long history of gradual optimisation in compiling quantum algorithms to fault-tolerant circuits.

Billions in Bitcoin at risk

The implications are significant. Approximately 6.9 million Bitcoin, worth tens of billions of dollars, currently sits in wallets that would be vulnerable to this type of quantum attack.

The threat extends beyond Bitcoin. Most blockchain technologies and cryptocurrencies rely on ECDLP-256 for critical aspects of their security. The growth of stablecoins and tokenised real-world assets means traditional financial instruments are increasingly governed by the same vulnerable code.

And cryptocurrency is only the starting point. The same elliptic curve cryptography underpins bank logins, health records, government systems and secure communications worldwide.

A new disclosure model

Google’s researchers took an unusual approach to publishing their findings. Rather than releasing the quantum circuits themselves, the team developed what they describe as a zero-knowledge proof, a cryptographic construction that allows third parties to verify the claims without gaining access to the underlying attack details.

“We’re exploring a new model for how to elucidate the code-breaking capabilities of future quantum computers and outlining steps that should be taken to mitigate their consequences,” Babbush and Neven wrote.

The pair noted that the team engaged with the US government before publication and urged other research teams to adopt similar practices.

“We want to raise awareness on this issue and are providing the cryptocurrency community with recommendations to improve security and stability before this is possible,” the researchers stated.

Responsible disclosure in a fragile ecosystem

The whitepaper devotes considerable attention to the politics of vulnerability disclosure in the cryptocurrency space.

Google’s researchers acknowledged that cryptocurrencies are not simply decentralised data processing systems. Their value as digital assets derives both from the digital security of the network and public confidence in the system.

That creates a unique problem. While digital security can be attacked using cryptographically relevant quantum computers, public confidence can also be undermined through fear, uncertainty and doubt.

The researchers warned that unscientific and unsubstantiated resource estimates for quantum algorithms breaking ECDLP-256 “can themselves represent an attack on the system.”

It is a fine line. Google wants the industry to act with urgency, but without triggering a panic that could destabilise markets.

Post-quantum cryptography as the path forward

Google has been working on post-quantum cryptography since 2016 and argues it represents a well-understood path to securing blockchains against future quantum attacks.

The whitepaper provides examples of post-quantum blockchains and experimental deployments of quantum-resistant cryptography on otherwise vulnerable chains.

However, the researchers cautioned that while viable solutions exist, they will take time to implement, bringing increasing urgency to act now.

In the short term, Google recommends that cryptocurrency users refrain from exposing or reusing vulnerable wallet addresses. The paper also raises potential policy options for addressing abandoned cryptocoins that can never be migrated to quantum-safe wallets.

Industry collaboration

Google indicated it is working alongside several organisations on the transition, including Coinbase, the Stanford Institute for Blockchain Research and the Ethereum Foundation.

The company framed its 2029 migration timeline as a benchmark for the broader industry.

“We look forward to continuing our work across the industry following our 2029 timeline alongside others working on responsible approaches,” the researchers wrote.

The canary in the coal mine

Charles Guillemet, CTO of Ledger and a cryptographer, pointed to the broader significance of Google’s findings.

The threat to cryptocurrency, he argued, should be understood as an early warning for a much wider security problem. The same encryption under scrutiny in Google’s paper protects banking infrastructure, medical records, government communications and corporate systems globally.

Google’s 2029 deadline applies to its own systems, but the clock is ticking for every organisation that relies on elliptic curve cryptography.

The whitepaper concludes by calling for further discussion among quantum computing researchers, security professionals, cryptocurrency stakeholders and policymakers to establish responsible disclosure norms for quantum cryptanalysis research.

“With this work, our goal is to support the long-term health of the cryptocurrency ecosystem and blockchain technologies, which are an increasingly significant part of the digital economy,” the researchers wrote.

Last Updated on April 1, 2026 by Nick Ross