Attacking Bitcoin Mining With a Quantum Computer Would Need the Energy of a Star

[NightCrawler81]

This CoinDesk piece from April deserves more attention than it got. BTQ Technologies published research titled Kardashev Scale Quantum Computing for Bitcoin Mining which establishes in fairly brutal mathematical terms why quantum computers cannot practically threaten Bitcoin's mining process. To competitively mine Bitcoin using Grover's algorithm, the quantum approach that theoretically speeds up the hash search, you would need approximately 10^23 physical qubits and 10^25 watts of power at Bitcoin's January 2025 difficulty level. That power requirement approaches the total energy output of a star. Not a power station. A star. Separately, a second paper referenced in the CoinDesk piece reportedly replicates every major quantum factoring breakthrough of recent years using a 1981 home computer.

This matters because public discourse about quantum threats to Bitcoin frequently conflates two completely different attack surfaces. Mining security and wallet security are separate problems. Mining via Grover is essentially impossible at any foreseeable scale of quantum hardware. Wallet security via Shor's algorithm is a genuine long-term concern because it targets elliptic curve cryptography rather than the hash function. The practical threat to Bitcoin is not that a quantum miner will dominate block production, it is that a sufficiently advanced quantum machine could eventually derive private keys from exposed public keys. That threat is real but distant and addressing it requires different technical solutions than mining security.

Attacking bitcoin mining with a quantum computer would require the energy of a star, academics say

https://www.coindesk.com/tech/2026/04/08/attacking-bitcoin-mining-with-a-quantum-computer-would-require-the-energy-of-a-star-academics-say

[BretHart88]

The stellar energy number is genuinely funny. It is the academic equivalent of saying this is not happening, ever, under any realistic physical constraints