1. Can quantum computers break Bitcoin?
Not with today’s technology. A sufficiently powerful fault-tolerant quantum computer could theoretically attack Bitcoin’s elliptic-curve signatures, but existing quantum systems lack the reliable logical qubits required to perform such attacks at scale.
2. How many quantum qubits would be needed to threaten cryptocurrency?
Ethereum’s quantum-resistance roadmap cites March 2026 Google Quantum AI research estimating roughly 1,200 logical qubits to attack 256-bit elliptic-curve cryptography. Logical qubits require substantial error correction and should not be confused with raw physical-qubit counts.
3. What is post-quantum cryptography?
Post-quantum cryptography uses algorithms designed to remain secure against conventional and quantum computers. NIST has standardized algorithms including ML-KEM, ML-DSA and SLH-DSA as part of preparations for future quantum threats.
4. Is Ethereum becoming quantum-resistant?
Ethereum is actively researching quantum-resistant infrastructure. Its roadmap includes post-quantum interoperability devnets, hash-based leanXMSS signatures and leanVM, with core post-quantum infrastructure currently targeted for approximately 2029, subject to roadmap changes.
5. What would happen to existing crypto wallets if quantum computers became powerful enough?
Networks could need new signature schemes and mechanisms for users to migrate funds to quantum-resistant wallets. The transition would require coordination among developers, users, exchanges, custodians, validators or miners before practical quantum attacks emerge.
