A Nobel Prize-winning physicist who helped build Google’s quantum computers has warned that Bitcoin could be one of the technology’s first real targets.
In an interview with CoinDesk, John M. Martinis said that recent Google research showing how a quantum computer could break Bitcoin encryption in minutes should be taken seriously.
“I think it’s a very well-written article. It lays out where we are right now,” Martinis said, referring to Google’s latest work on quantum threats to cryptography. “It’s not something with zero probability; people have to deal with it.”
READ: A Simple Explanation of What Quantum Computing Really Is and Why It’s Terrifying for Bitcoin
The Google paper explains how a sufficiently advanced quantum computer could derive a Bitcoin private key from its public key, potentially within minutes, thereby significantly reducing the computational barrier that currently secures the network, Martinis pointed out, adding that this is one of the issues that needs to be taken most seriously.
READ: This is what quantum computers actually mean to “crack” bitcoin in 9 minutes
Although the idea of quantum computers breaking encryption is often presented as remote or theoretical, Martinis said one of the first practical applications could be much more immediate.
The Lowest Fruit for Quantum Computers
“It turns out that decrypting cryptography is one of the simplest applications of quantum computing because it is very digital,” he said. “These are the smallest, simplest algorithms. The lowest hanging fruit.”
This puts Bitcoin, which relies on elliptic curve cryptography, directly in the crosshairs, Martinis suggested, confirming what the Google paper warns.
Unlike traditional financial systems, which can migrate to quantum-resistant encryption standards, bitcoin faces a more complex challenge. Its decentralized structure and historic design make upgrades slower and more controversial, the Nobel laureate said.
“You can use quantum-resistant codes” in banking and other systems, Martinis said. “Bitcoin is a little different, which is why people should think about it now.”
The issue focuses on a specific vulnerability window. When a Bitcoin transaction is broadcast, its public key becomes visible before being confirmed on-chain, Martinis explained. A powerful quantum computer could, in theory, use this window to derive the corresponding private key and redirect funds before final settlement, he noted.
However, Martinis cautioned against assuming the threat is imminent. Building a quantum computer capable of executing such an attack remains one of the most difficult technical challenges in modern science.
“I think it will be harder to build a quantum computer than people think,” he said, pointing to major hurdles in scaling, reliability and error correction.
No reason not to act
Estimates of when cryptographically relevant quantum machines might emerge vary widely. Martinis suggested a rough time frame of five to 10 years, but cautioned that uncertainty is not a reason for inaction.
“Given the serious consequences, you have to face it. You have time, but you have to work on it,” he said.
The warning highlights a growing shift within the quantum research community, where scientists are increasingly reporting risks to existing cryptographic systems while concealing sensitive technical details – a strategy borrowed from traditional cybersecurity disclosure practices.
For Bitcoin developers and investors, the message is increasingly difficult to ignore.
“The crypto community needs to plan for this,” Martinis said. “This is a serious problem that needs to 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 large-scale superconducting quantum computers.
