Quantum Computings Threat to Bitcoin Mining: Energy Needs of a Star

Quantum Computing Threat to Bitcoin Mining Requires Stellar Energy, Academics Say

According to a recent study, a quantum attack on the Bitcoin blockchain would necessitate energy production equivalent to that of a star. This research highlights that while quantum computers pose a long-term risk to Bitcoin, the current fears often conflate wallet vulnerabilities with largely impractical threats to mining.

New studies indicate that a quantum-based 51% attack on Bitcoin mining would require energy and hardware levels that are physically unattainable. The more realistic concern is that future quantum computers could target older or already exposed Bitcoin wallets, although developers are actively working on upgrades to fortify the network against such attacks.

"The energy required for a quantum mining fleet would be on the order of 10²⁵ watts, which is comparable to the energy output of a star," stated researchers involved in the study.

In January 2025, it was estimated that a quantum mining fleet would need approximately 10²³ qubits to operate effectively. In contrast, the entire current Bitcoin blockchain consumes about 15 gigawatts of power.

Key Takeaway: A quantum attack on Bitcoin mining is not only costly but also physically unfeasible with current technology.

Debunking Quantum Factorization Breakthroughs

The second paper, authored by Peter Gutmann from the University of Auckland and Stephan Neuhaus from Zurich University, critiques the ongoing narrative that quantum computers are beginning to crack encryptions. They successfully replicated every significant breakthrough in quantum factorization over the last two decades using a VIC-20 home computer from 1981, an abacus, and a dog named Scribble.

This humorous approach underscores a serious point: factorization, the mathematical problem underpinning most modern encryption, is still practically impossible on standard computers. The authors argue that many demonstrations of quantum factorization have been misleading, often using simplified problems that do not reflect real-world cryptography.

For instance, they highlighted a recent claim by a Chinese team that used a D-Wave machine to make progress on RSA-2048 decryption. Gutmann and Neuhaus ran the same numbers through a VIC-20 emulator and obtained results in about 16 seconds, revealing that the numbers chosen were too close together, making them easier to guess.

Key Takeaway: Many claims of quantum breakthroughs in factorization may not represent genuine advancements in the field.

Ongoing Concerns and Future Developments

Neither of the studies dismisses the quantum threat entirely. The primary vulnerability lies in Bitcoin wallets, particularly older or reused addresses that have already disclosed critical information on the blockchain. A recent study from Google suggests that the computational power required for a quantum attack could decrease significantly, making the encryption securing the Bitcoin blockchain vulnerable to attacks that could be executed in minutes.

However, the authors clarify that building such a machine is currently physically impossible and would require technological advancements that have yet to be achieved. Developers are already working on solutions to mitigate key exposure and new signature types designed to withstand quantum attacks.

Key Takeaway: While the quantum threat to Bitcoin is real, the construction of machines capable of executing such attacks is limited by the laws of physics.

Sources:

• Der Angriff auf das Bitcoin-Mining mit einem Quantencomputer würde nach Angaben von Akademikern die Energie eines Sterns erfordern