BTQ Study Finds Quantum Bitcoin Mining Would Require Star-Level Energy, Cites Signature Vulnerability as Bigger Threat

BTQ Technologies Corp. published a research paper on April 8, 2026 establishing the first end-to-end physical cost estimate for using quantum computers to mine Bitcoin, concluding that even under the most favorable assumptions a quantum mining fleet would require approximately 10^8 qubits and 10^4 megawatts of power — roughly the output of a large national electricity grid — and at Bitcoin’s January 2025 difficulty would scale to 10^23 qubits and 10^25 watts, approaching the energy output of a star.

The study finds that quantum-accelerated mining using Grover’s algorithm is physically and economically impractical, while quantum attacks on Bitcoin’s elliptic-curve signatures using Shor’s algorithm remain a genuine and more immediate concern, reinforcing the need for post-quantum cryptographic infrastructure.

Quantum Mining Energy Estimates Exceed Civilization’s Capacity

The paper, titled “Kardashev Scale Quantum Computing for Bitcoin Mining” by Pierre-Luc Dallaire-Demers and published on arXiv, models the full quantum mining stack including reversible double-SHA-256 oracles, surface-code magic-state distillation factories, fleet-scale qubit logistics, and the timing constraints imposed by Nakamoto consensus. Even under a highly favorable partial-preimage setting, a superconducting surface-code fleet would require approximately 10^8 physical qubits and 10^4 megawatts of power, comparable to a large national electricity grid.

At Bitcoin’s January 2025 mainnet mining difficulty, estimated requirements rise to approximately 10^23 physical qubits and 10^25 watts — approaching the energy output of a star. Every step of the search involves hundreds of thousands of delicate operations, each requiring dedicated support systems. Because Bitcoin produces a new block every ten minutes, an attacker would have only a narrow window to finish the job, forcing them to run enormous numbers of machines side by side. By comparison, the entire current Bitcoin blockchain draws about 15 gigawatts.

The study concludes that while Grover’s algorithm offers a quadratic search advantage in theory, that benefit breaks down once oracle construction, error correction, and fleet overhead are included. Quantum mining is not a credible near-term threat to Bitcoin’s proof-of-work consensus.

Signature Vulnerability Remains the Immediate Concern

By contrast, quantum attacks on Bitcoin’s elliptic-curve signatures using Shor’s algorithm are a genuine and more urgent challenge. Millions of bitcoin sit in older or reused addresses where public keys are already exposed on the blockchain, making them the most likely long-term target if quantum machines improve. The paper reinforces the need for post-quantum cryptographic infrastructure, a view consistent with BTQ’s broader strategy.

Through its Bitcoin Quantum initiative, BTQ has been developing and testing a quantum-safe Bitcoin architecture, including NIST-standardized ML-DSA signatures and transaction designs such as BIP 360 (Pay-to-Merkle-Root). The company previously launched a Bitcoin Quantum testnet as a live environment for demonstrating how Bitcoin-like systems can migrate toward post-quantum standards.

Academic Papers Question Quantum Factoring ‘Breakthroughs’

A separate paper by Peter Gutmann of the University of Auckland and Stephan Neuhaus of Zürcher Hochschule takes aim at headlines claiming quantum computers are already breaking encryption. The authors replicated major quantum factoring “breakthroughs” of the past two decades using a 1981 VIC-20 home computer, an abacus, and a dog trained to bark three times.

The researchers argue that nearly every demonstration so far has cheated. In some cases, researchers picked numbers whose hidden prime factors were only a few digits apart, making them easy to guess with a basic calculator trick. In others, they performed preprocessing on a classical computer before handing a stripped-down version to the quantum machine. The paper proposes new evaluation standards requiring random numbers, no preprocessing, and factors kept secret from experimenters. No demonstration to date would pass.

Google Research Suggests Lower Qubit Estimates, But Engineering Hurdles Remain

Since these papers were published, a recent study from Google Quantum AI suggests the computing power needed for an attack on Bitcoin’s encryption could fall sharply, with estimates requiring 1,200 to 1,450 logical qubits. However, the authors disclose that building such a machine is currently physically impossible and requires engineering advances that have not yet been achieved, including lasers to control qubits, readout speed, and the ability to keep tens of thousands of atoms running in concert without losing them.

Some recent research has withheld key technical details, and experts have warned that progress in this field may not always be shared openly. Developers are already working on fixes, including ways to reduce key exposure and new types of signatures designed to withstand quantum attacks.

Industry Response and Post-Quantum Roadmap

BTQ’s paper also introduces the rationale for Quantum Proof of Work (QPoW), a quantum-native consensus model built around computational tasks designed for quantum hardware from the outset. In modeled comparisons, BTQ indicates that a quantum sampler in QPoW consumes approximately 0.25 kWh over a 10-minute block interval versus approximately 390 kWh per block per miner for a classical equivalent sampling-based setup, implying an energy advantage of approximately 1,560x.

Markets currently reflect the view that this threat is still distant. Traders see little chance that Bitcoin will replace its mining algorithm before 2027, but assign higher odds, around 40%, to upgrades like BIP-360 aimed at reducing wallet risk.

FAQ

How much energy would a quantum computer need to mine Bitcoin?

At Bitcoin’s January 2025 difficulty, a quantum mining fleet would require approximately 10^23 physical qubits and 10^25 watts — approaching the energy output of a star. Even in the most optimistic scenario, a fleet would need 10^8 qubits and 10^4 megawatts, comparable to a large national electricity grid.

Is the threat of quantum computers to Bitcoin mining real?

According to the BTQ study, quantum-accelerated mining using Grover’s algorithm is physically and economically impractical due to astronomical qubit and energy requirements. The more urgent threat is quantum attacks on Bitcoin’s digital signatures, which could expose funds in older or reused wallets.

What is being done to prepare for quantum threats to Bitcoin?

Developers are working on post-quantum cryptographic standards, including BIP 360 (Pay-to-Merkle-Root) and NIST-standardized ML-DSA signatures. BTQ has launched a Bitcoin Quantum testnet to demonstrate migration paths, and alternative consensus models such as Quantum Proof of Work are being explored.