Google Quantum AI cautions 256-bit ECC could be broken with fewer qubits than previously thought

Google Quantum AI has published a whitepaper cautioning that 256-bit elliptic-curve cryptography (ECC)—a standard securing many crypto wallets—may be crackable with less quantum hardware than earlier estimates suggested. The paper says the task could be completed in minutes using fewer than 500,000 physical qubits. Google is urging the industry to speed up the shift to post-quantum cryptography (PQC). Dragonfly Managing Partner Haseeb said the work improves ECDSA cracking efficiency by about 20x, bringing forward expectations for a broader PQC migration to around 2029. He added that Google treated the findings with notable caution, validating the results with ZK proofs without disclosing the underlying quantum circuits.