Nobel Prize–winning physicist John M. Martinis, who helped build Google’s quantum computers, warned that bitcoin may be among the earliest real-world targets of quantum technology. In an interview with CoinDesk, Martinis pointed to recent Google research showing how a quantum computer could break bitcoin encryption in minutes. “I think it’s a very well-written paper. It lays out where we are right now,” he said. “It’s not something that has zero probability; people have to deal with this.”
Google paper: Deriving a private key from a public key in minutes
Martinis highlighted that the Google paper outlines how a sufficiently advanced quantum computer could derive a bitcoin private key from its public key within minutes, drastically reducing the computational barrier that currently secures the network. He stressed that this is one of the issues that must be taken most seriously.
While the idea of quantum computers breaking encryption is often framed as distant or theoretical, Martinis said one of the first practical applications may be far more immediate. “It turns out that breaking cryptography is one of the easier applications for quantum computing, because it’s very numeric. These are the smaller, easier algorithms. The low-hanging fruit.” That places bitcoin, which relies on elliptic-curve cryptography, directly in the line of fire.
Bitcoin’s decentralization makes upgrades harder
Unlike traditional financial systems that can migrate to quantum-resistant encryption standards, bitcoin faces a more complex challenge. “You can go to quantum-resistant codes in banking and other systems. Bitcoin is a little bit different, which is why people should be thinking about this right now,” Martinis said.
The concern centers on a specific vulnerability window: when a bitcoin transaction is broadcast, its public key becomes visible before it is confirmed on-chain. A powerful quantum computer could theoretically use that window to derive the private key and redirect funds before final settlement.
However, Martinis cautioned against assuming the threat is imminent. “I think it’s going to be harder to build a quantum computer than people are thinking,” he said, pointing to major hurdles in scaling, reliability and error correction.
Five- to ten-year window, but inaction is not an option
Estimates for when cryptographically relevant quantum machines could emerge vary widely. Martinis suggested a rough five- to ten-year window, but warned that uncertainty is not a reason for inaction. “Given the serious consequences, you deal with it. You have time, but you have to work on it.”
The warning highlights a growing shift inside the quantum research community, where scientists are increasingly flagging risks to existing cryptographic systems while withholding sensitive technical details — a strategy borrowed from traditional cybersecurity disclosure practices. “The crypto community has to plan for this. It’s a serious issue that has to be dealt with,” Martinis said.
Martinis, who won the 2025 Nobel Prize for his work on macroscopic quantum phenomena, formerly led Google’s quantum hardware program (including the 2019 “quantum supremacy” experiment) and is now CTO and co‑founder of Qolab, a company developing utility‑scale superconducting quantum computers.