A Nobel Prize-winning physicist who helped build Google’s quantum computer has warned that Bitcoin could become one of the technology’s earliest real-world targets.
In an interview with CoinDesk, Dr. John M. Martinis said that recent Google research showing how quantum computers can break Bitcoin encryption in minutes should be taken seriously.
“I think this is a very well-written paper. It shows where we are right now,” Martinis said, referring to Google’s latest work on quantum threats to cryptography. “The odds are not zero. People have to deal with this.”
Read: A quick explanation of what quantum computing actually is and why it’s scary for Bitcoin
Google’s paper outlines how a sufficiently advanced quantum computer could derive Bitcoin’s private key from its public key, potentially within minutes, dramatically reducing the computational barriers that currently protect the network, Martinis stressed, adding that this is one of the issues that should be taken most seriously.
Read: What does a quantum computer “crack” Bitcoin in 9 minutes actually mean?
While the idea of quantum computers cracking codes is often seen as far-fetched or theoretical, Martinis said one of the first practical applications could come much sooner.
The lowest hurdle for quantum computers
“It turns out that breaking codes is one of the simplest applications of quantum computing, because codes are very numerical,” he said. “These are smaller, simpler algorithms. They’re low-hanging fruit.”
This puts Bitcoin, which relies on elliptic curve cryptography, under direct attack, Martinis suggested, confirming what Google’s paper warns about.
Unlike traditional financial systems that can transition to quantum-resistant encryption standards, Bitcoin faces more complex challenges. The Nobel laureate said its decentralized structure and historic design would make upgrades slow and controversial.
Martinis said banks and other systems “have access to quantum-resistant cryptography.” “Bitcoin is a little different. That’s why people should be thinking about this now.”
Concerns are focused on specific vulnerability windows. Martinis explained that when a Bitcoin transaction is broadcast, its public key is visible before being verified on-chain. In theory, a powerful quantum computer could use that window to derive the corresponding private key and redirect funds before final settlement, he noted.
But Martinis cautioned against assuming the threat is imminent. Building a quantum computer capable of carrying out such attacks remains one of the most difficult engineering challenges in modern science.
“Building a quantum computer will be harder than people think,” he said, pointing to major hurdles in scaling, reliability and error correction.
There’s no reason to do nothing
Estimates about when cryptographically relevant quantum machines will emerge vary widely. Martinis suggested a rough five- to 10-year time horizon, but cautioned that uncertainty is no reason for not taking action.
“Given the serious consequences, we have to deal with it. We have time, but we have to work with it,” he said.
This warning highlights growing change within the quantum research community. Scientists are increasingly warning of risks to existing cryptographic systems while withholding details of sensitive technology, a strategy borrowed from traditional cybersecurity disclosure practices.
This message is becoming difficult to ignore for Bitcoin developers and investors alike.
“The crypto community needs to plan for this,” Martinis said. “This is a serious issue that must be addressed.”
Martinis is a 2025 Nobel Prize-winning physicist recognized for his work on macroscopic quantum phenomena, and is widely known for leading Google’s quantum hardware program, including the 2019 “Quantum Supremacy” experiment. He is currently CTO and co-founder of Qolab, a hardware company developing utility-scale superconducting quantum computers.
