The notion that quantum computing poses an imminent threat to bitcoin has been a recurring theme in recent headlines, with some claiming that future machines could potentially crack its cryptography or overwhelm the network. However, academic research presents a more nuanced picture, suggesting that certain 'breakthroughs' rely on oversimplified problems that do not accurately reflect real-world cryptography.
Furthermore, the energy required for a quantum attack on bitcoin is estimated to be equivalent to that of a small star. Bitcoin's security is based on two types of mathematics, and quantum computers pose a threat to them in two distinct ways.
The first, known as Shor's algorithm, targets wallet security by potentially allowing a powerful quantum computer to derive a private key from a public key, thereby giving an attacker control over funds. The second, known as Grover's algorithm, applies to mining and offers a theoretical speedup on the trial-and-error search process miners use. However, the advantage of Grover's algorithm largely disappears when attempting to build the machine.
Two recent papers highlighted the challenges of quantum attacks on bitcoin. The first paper, published in March 2026, examines whether a quantum computer could outmine bitcoin using Grover's algorithm. The researchers conclude that running the algorithm against the math formula bitcoin miners use would be physically impossible, requiring quantum hardware on a scale that is currently unknown and an enormous amount of energy, approximately 10²³ qubits drawing 10²⁵ watts, which is comparable to the energy output of a star. The second paper takes aim at the steady stream of headlines claiming that quantum computers are breaking encryption.
The authors successfully replicate every major quantum factoring 'breakthrough' of the past two decades using a 1981 VIC-20 home computer, an abacus, and a dog, demonstrating that many of these breakthroughs are exaggerated or rely on simplified problems. The researchers suggest that the incentive to publish impressive-sounding results is strong, leading to the selection of rigged numbers or the completion of most of the work classically, allowing researchers to claim new 'records' without advancing the underlying science.
While the papers do not dismiss the quantum threat entirely, they suggest that the real vulnerability lies in bitcoin wallets, not mining, and that the estimated computing power needed for an attack could fall sharply. Developers are already working on fixes, including ways to reduce key exposure and new types of signatures designed to withstand quantum attacks.