Two new academic studies downplay quantum threats to Bitcoin, proving that an attack on mining is physically unfeasible.
Two recent academic papers, shared on X by NVK, offer a far more sober picture than the alarmist headlines that periodically rattle crypto markets. The first study, authored by Pierre-Luc Dallaire-Demers and the team at BTQ Technologies and published in March 2026, analyzes the feasibility of a quantum attack on Bitcoin mining. The second, authored by Peter Gutmann of the University of Auckland and Stephan Neuhaus of the Zürcher Hochschule in Switzerland, systematically dismantles every alleged quantum factorization “breakthrough” of the past twenty years.
Bitcoin’s security relies on two distinct types of cryptography, and quantum computers threaten them in different ways. Shor’s algorithm targets wallet security: in theory, it would allow a sufficiently powerful quantum computer to derive a private key from a public key, enabling an attacker to seize funds. Grover’s algorithm, on the other hand, applies to mining, offering a theoretical speedup in the search process that miners perform to find valid blocks. These two threats are often conflated in newspaper headlines, but they carry very different implications once real physical limitations are taken into account.
The BTQ Technologies paper examines whether a quantum computer could actually outpace Bitcoin miners using Grover against SHA-256, the mathematical function underpinning the mining process. The conclusions are clear-cut: at January 2025 mining difficulty, a fleet of quantum miners would need approximately 10²³ qubits consuming 10²⁵ watts of energy – an amount equal to roughly 3% of the Sun’s energy output. By comparison, the entire current Bitcoin network consumes around 15 gigawatts. Each step of the algorithm would require hundreds of thousands of delicate operations, each supported by thousands of qubits dedicated to error correction. A quantum 51% attack, the researchers conclude, is not merely expensive – it is physically unfeasible at any scale a real civilization could power.
The second paper takes a deliberately satirical approach to make a serious point. Gutmann and Neuhaus replicated every major quantum factorization “breakthrough” using a 1981 VIC-20 home computer, an abacus, and a dog named Scribble trained to bark three times. The joke works because the underlying problem is real: nearly all demonstrations published to date have used numbers with prime factors very close to each other, easily identified through an algorithmic trick dating back to John von Neumann in 1945, or have performed the hard part of the computation on a classical computer before passing a simplified version to the quantum computer. In the specific case of a paper claiming progress toward breaking RSA-2048, the Auckland researchers recovered the answers for all ten sample numbers provided as evidence in approximately 16 seconds each using a VIC-20 emulator.
Neither paper entirely dismisses the long-term quantum threat. The most concrete vulnerability concerns Bitcoin wallets, particularly older or reused addresses, where public key information is already exposed on the blockchain. A recent Google study suggests that the computational power required for such an attack could decrease significantly, making wallet cryptography potentially vulnerable in an attack that would take only a few minutes – although the authors themselves note that building such a machine remains physically impossible and requires engineering advances not yet achieved. Developers are already working on solutions, including BIP-360, a proposal aimed at reducing key exposure and introducing new quantum-resistant signature types.
