Dr. John Martinis, a 2025 Nobel Prize in Physics recipient and former Google quantum hardware head, cautions that cracking encryption will likely be the first practical application of quantum computing

Research-supported warning identifies encryption as a primary practical use for advanced quantum systems. (Planet Volumes-Unsplash/Modified by CoinDesk)

Key Takeaways:

• John M. Martinis, a Nobel laureate instrumental in developing Google’s quantum computers, cautions that Bitcoin might be the first real-world target of quantum attacks.
• He supports a recent Google study demonstrating that a sufficiently advanced quantum computer could extract a Bitcoin private key from its public key in minutes, taking advantage of the short period when a transaction’s public key is exposed.
• Although Martinis estimates constructing such machines could take five to ten years and remains a significant engineering hurdle, he urges the Bitcoin community to begin planning for quantum-resistant upgrades despite the network’s sluggish, decentralized governance.

A Nobel Prize–winning physicist who contributed to the development of Google’s quantum computers cautioned that Bitcoin BTC$68,399.76 could be among the first real-world applications targeted by this technology.

In a discussion with CoinDesk, Dr. John M. Martinis stated that recent Google research illustrating how a quantum computer might compromise Bitcoin encryption within minutes warrants serious attention.

“I believe it is a very well-crafted paper. It outlines our current position,” Martinis remarked, referencing Google’s newest work regarding quantum threats to cryptography. “It is not something with zero probability; people must address this.”

READ: A simple explainer on what quantum computing actually is, and why it is terrifying for bitcoin

The Google paper details how a sufficiently advanced quantum computer could calculate a Bitcoin private key from its public key, potentially in a matter of minutes, significantly lowering the computational barrier currently securing the network, Martinis noted, emphasizing this is a critical issue that must be prioritized.

READ: Here’s what ‘cracking’ bitcoin in 9 minutes by quantum computers actually means

Although the concept of quantum computers breaking encryption is often portrayed as distant or purely theoretical, Martinis noted that one of the first practical uses may be much more immediate.

Most accessible targets for quantum computers

“It appears that breaking cryptography is one of the more straightforward applications for quantum computing, as it is highly numeric,” he stated. “These are the smaller, simpler algorithms. The low-hanging fruit.”

This puts Bitcoin, which depends on elliptic curve cryptography, directly in the crosshairs, Martinis suggested, validating the warnings in the Google paper.

Unlike traditional financial systems, which can transition to quantum-resistant encryption standards, Bitcoin presents a more intricate challenge. Its decentralized nature and historical design make upgrades slower and more contentious, the Nobel Prize winner stated.

“You can switch to quantum-resistant codes” in banking and other systems, Martinis said. “Bitcoin is somewhat different, which is why people should be considering this right now.”

The concern focuses on a specific vulnerability window. When a Bitcoin transaction is broadcast, its public key becomes visible before it is confirmed onchain, Martinis explained. A powerful quantum computer could, in theory, utilize that window to derive the corresponding private key and redirect funds before final settlement, he noted.

However, Martinis cautioned against assuming the threat is imminent. Constructing a quantum computer capable of executing such an attack remains one of the most difficult engineering challenges in modern science.

“I believe it will be more difficult to build a quantum computer than people are expecting,” he said, highlighting major hurdles in scaling, reliability and error correction.

No justification for inaction

Projections for when cryptographically relevant quantum machines could appear vary significantly. 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,” he said.

The warning underscores a growing shift within 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.

For Bitcoin developers and investors alike, the message is becoming harder to ignore.

“The crypto community has to plan for this,” Martinis said. “It’s a serious issue that has to be dealt with.”

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.

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