Alice & Bob's quantum computer research suggests 30,000 cat qubits could crack a Bitcoin private key in one hour, prompting calls for post-quantum cryptography adoption.
Regulation & Gov ·
Alice & Bob, a quantum computing firm, released a preprint estimating that roughly 30,000 of its cat qubits—a superconducting design that suppresses bit-flip errors—could compromise a Bitcoin private key within approximately one hour, targeting the secp256k1 elliptic curve used in Bitcoin signatures. The calculation, posted to the IACR Cryptology ePrint Archive, places the physical qubit requirement at no more than 29,588 and the time at 61.8 minutes. The company's cat-qubit architecture reduces the number of physical qubits needed by handling bit-flip errors in hardware rather than through additional error-correction overhead.
The estimate rests on a critical assumption: zero bit-flip errors during computation, equivalent to a century-long error window. Should bit-flips occur roughly hourly instead, the qubit requirement for breaking RSA-2048 balloons from 22,593 to approximately 45,000. This ceiling matters because Alice & Bob's largest current demonstrator operates on a 12-qubit chip, nowhere near the scale needed. The one-hour attack window also exceeds Bitcoin's 10-minute block interval, making real-time transaction interception infeasible under current network conditions.
Alice & Bob has called for immediate migration to post-quantum cryptography, citing proposals such as BIP-361, which would phase out quantum-vulnerable legacy address types. The company anticipates hardware advances and resource-estimate refinements will intersect in the early 2030s, framing the transition window as urgent despite current technological distance from the required scale.