Alice & Bob’s model cuts hardware needed to break Bitcoin keys by about 17 times

The Paris quantum firm estimates roughly 30,000 physical qubits could crack Bitcoin wallet cryptography in just over an hour The estimated size of a computer capable of breaking Bitcoin’s cryptography just got a lot smaller. Researchers at Paris-based quantum computing firm Alice & Bob say a machine with about 30,000 physical qubits could derive a Bitcoin private key from its public key in just over an hour. Their message to Bitcoin developers is to start the move to quantum-resistant security now, because the upgrade itself could take years. From millions of qubits to tens of thousands Some context on how fast this number has been falling. Earlier estimates put the hardware needed to crack Bitcoin’s cryptography in the millions of physical qubits. In March 2026, Google Quantum AI cut that figure to fewer than 500,000 physical qubits. Alice & Bob’s model now lands at around 30,000. Measured against Google’s upper bound, that is roughly 17 times less hardware. The target is secp256k1, the elliptic-curve cryptography that protects Bitcoin wallets. The attack method is Shor’s algorithm, a quantum routine that can, in principle, work backward from a public key to the private ke...