Concerns Over Quantum Computing and Bitcoin Security

Headlines increasingly warn that Bitcoin might be on the edge of disaster, as emerging quantum machines promise to breach its encryption within minutes or overwhelm the entire network. Yet, academic studies offer a more nuanced perspective. Many high-profile “breakthroughs” hinge on simplified problems that don’t align with actual cryptographic practices. Regarding a quantum assault on Bitcoin, a recent paper shared on X by Bitcoin hardware entrepreneur Rodolfo Novak argues that the energy needed for such an attack could rival that of a small star.

Bitcoin’s defense relies on two distinct mathematical frameworks, with quantum computing presenting threats in two separate ways.

The first, Shor’s algorithm, poses a risk to wallet security. In theory, a sufficiently advanced quantum computer could deduce a private key from a public key, granting the attacker full control over the funds and undermining the ownership principles central to Bitcoin.

The second threat derives from Grover’s algorithm, which impacts mining processes, theoretically enhancing the trial-and-error attempts miners make to find valid blocks. However, as shown in one of the papers discussed, this advantage may dissipate when attempting to construct a functioning machine.

These two threats often get blurred in sensational headlines, but they have very different implications when viewed through the lens of practical realities.

Mining and Physical Limitations

The first paper, from Pierre-Luc Dallaire-Demers and the BTQ Technologies team, published in March 2026, questions whether quantum computers could actually mine Bitcoin using Grover’s algorithm. This algorithm enables computers to tackle problems significantly faster than conventional machines, thus speeding up miners’ search for valid blocks.

The stakes are higher than one might assume. Mining serves as a shield against 51% attacks, where a single entity could commandeer enough hashing power to manipulate transaction history, confirming transactions or double-spending coins. If quantum miners dominated block generation, the very consensus mechanism could falter.

While Grover theoretically provides a way to achieve such a competitive edge, the researchers contend that its feasibility crumbles under scrutiny of hardware and energy costs. Competing with SHA-256, the formula Bitcoin miners use to solve problems and earn rewards, would be physically implausible.

Operating algorithms on Bitcoin would necessitate quantum hardware on an unprecedented scale, something currently unknown how to produce.

Each step in the mining process requires an array of intricate operations, with dedicated support systems of thousands of qubits to minimize errors. Since Bitcoin generates new blocks every ten minutes, a prospective attacker would have a limited window to execute their plan, necessitating a vast number of machines running simultaneously.

According to the authors, achieving a viable quantum mining setup at Bitcoin’s January 2025 difficulty level would necessitate around 10²³ qubits operating on 10²⁵ watts, a figure nearing the energy output of a star. For context, the current Bitcoin blockchain consumes about 15 gigawatts.

Not only are quantum 51% attacks prohibitively expensive, but achieving them on any conceivable scale is currently out of reach for even advanced civilizations.

Critiquing Quantum Breakthroughs

The second paper, authored by Peter Guttmann from the University of Auckland and Stefan Neuhaus from Zurich University, addresses the growing frequency of claims that quantum computers have already begun to undermine cryptography.

The authors attempted to replicate major quantum factorization “achievements” from the past twenty years. In a humorous twist, they succeeded using a 1981 VIC-20 home computer, an abacus, and even a dog named Scribble trained to bark three times.

This light-hearted approach underscores a grave reality. Factorization is a crucial mathematical problem underpinning modern cryptography, which involves identifying prime factors of a large number. For numbers with several hundred digits, conventional computers are generally deemed incapable of solving them. Schor’s algorithm, the quantum technology raising alarms over Bitcoin wallets, is a potential game-changer.

But Guttmann and Neuhaus assert that nearly all previous claims of success were inflated. Many instances involved researchers choosing numbers with closely related prime factors, making them easy to uncover with basic techniques.

In other cases, a routine computer conducted the challenging parts of the task before passing an oversimplified version to a quantum machine for resolution. While the excitement for quantum computers is palpable, much of the groundbreaking work has occurred elsewhere.

The authors reference a recent study where a Chinese team reportedly advanced toward cracking RSA-2048, a standard protecting a significant portion of online banking and e-commerce security. This research presented ten numeric cases as evidence, but Guttmann and Neuhaus replicated their findings on a VIC-20 emulator, uncovering answers in about 16 seconds, thanks to clever number selection.

Why do these discrepancies persist? The authors propose a straightforward explanation: quantum factorization is a trendy field, ripe with limited actual findings, incentivizing researchers to publish impressive results.

By selecting misleading numbers or rehashing established studies, researchers can claim groundbreaking “records” without genuinely advancing the underlying science. They propose a new assessment standard requiring random numbers, with no preprocessing and secret coefficients to foil manipulation—ensuring no demonstration could pass.

The essence is not that quantum computing is a benign force. Not every “revolutionary” headline equates to substantive progress in code-breaking, and market participants should approach new claims with caution.

A Continued Threat

Neither of the studies wholly dismisses the quantum threat.

The primary vulnerability lies within Bitcoin wallets, not in mining. Millions of Bitcoins are held in outdated or repurposed addresses where sensitive data is already publicly accessible on the blockchain, making them prime targets if quantum computing advances.

What has shifted since the release of these studies is less about the nature of the threat and more about the estimates. Recent research from Google indicates that the computational power required for such attacks could diminish quickly, with the encryption safeguarding the Bitcoin blockchain becoming susceptible to breaches taking mere minutes.

However, this doesn’t imply that an attack is imminent. The authors clarify that crafting such a machine remains physically impossible and would demand engineering breakthroughs yet to be realized, from lasers controlling qubits to managing up to tens of thousands of atoms in sync without loss.

Additionally, there are indications that certain public releases may not disclose comprehensive details. Some recent studies have withheld key technical elements, and experts caution that advancements in the field are not always shared transparently.

Nevertheless, developers are actively pursuing solutions, such as techniques to minimize key vulnerabilities and new signature types engineered to resist quantum assaults.

The market sentiment reflects that this threat is still a theoretical concern. Traders largely deem it improbable for Bitcoin to undergo significant shifts. Yet, there’s a belief in higher odds for upgrades aimed at addressing wallet vulnerabilities in the near future.

While the quantum threat to Bitcoin is tangible, it’s equally important to recognize the tangible limits in constructing machines capable of compromising blockchains.