IBM and IonQ’s advancements in quantum computing have sparked concern about the long-term security of Bitcoin. Experts are debating whether these groundbreaking machines could ultimately compromise Bitcoin’s intricate encryption mechanisms and defenses. 2,500 to 3 million qubits are estimated as the threshold needed to crack Bitcoin’s system. IonQ aims for 80,000 logical qubits by 2030, while IBM plans a scalable quantum computer with 200 logical qubits by 2029, and later, its Quantum Blue Jay system aiming for up to 2,000 logical qubits. These developments have reignited conversations about Bitcoin’s vulnerability to quantum computing threats. Can these machines potentially break the cryptography that secures Bitcoin? Despite recent progress in quantum technology, it remains theoretical. The current estimates on the potential impact of quantum computers on Bitcoin vary widely. Borovik suggests 13 million to 1.9 billion physical qubits would be needed for a successful attack, while others estimate figures closer to 300-317 million, or even as low as 13 million. The key lies in the conversion from unstable physical qubits into stable logical ones, which happens via technology and error correction. This means even with substantial qubit numbers, Bitcoin’s network might remain secure for now. However, some experts believe as little as 2,500 logical qubits could be enough to break Bitcoin’s encryption algorithm. Charles Edwards, founder of Capriole, believes only 2,500 logical qubits would be sufficient to compromise the network. Quantum physicists Anastasia Marchenkova share similar views, stating that 2,500 logical qubits could pose a threat. Bitcoin’s reliance on elliptic curve cryptography (ECDSA) for securing private keys and control over funds, adds another layer of complexity. While traditional computers would require billions of years to break this system, quantum computers may be able to solve specific mathematical problems faster. However, no known quantum computer currently possesses the capacity to crack Bitcoin’s encryption. The field is rapidly advancing but not at an exponential pace. However, the development community is taking action. In 2025, a Chilean developer proposed a hard fork, aiming for the adoption of quantum-resistant address formats and replacing ECDSA with post-quantum cryptographic systems. Ben Sigman, CEO of Bitcoin Libre, supported this approach, advocating for the BIP-360 upgrade, which could provide increased defense against quantum threats. Although still under discussion, this proposal signifies that Bitcoin is actively planning for mitigation strategies in light of potential future threats.