Alice & Bob researchers calculated that a theoretical quantum attack capable of breaking Bitcoin’s cryptography would require 29.588 physical qubits and about 62 minutes.
A new model from quantum computing company Alice & Bob suggests that the encryption protecting Bitcoin wallets could be broken with far less hardware than previously estimated. The calculation does not mean such an attack is possible today; it offers a theoretical estimate of the resources that could be needed in the future.
The researchers’ estimate of 29.588 physical qubits is about 17 times lower than Google’s estimate of under 500,000, shared in March. However, the two studies are based on different quantum computer designs and assumptions.
A 62-minute attack puts Bitcoin with visible public keys in focus
According to Alice & Bob’s calculation, the attack takes about 62 minutes. Since the average block time on Bitcoin is 10 minutes, that does not appear to be enough time to reliably intercept a pending transaction before it is confirmed.
The risk is different for Bitcoin in addresses whose public keys are already visible. A sufficiently powerful quantum computer could derive the private key from the public key and target these assets. According to the source, there are more than 6 million BTC in such addresses.
Dahmun Goudarzi, Alice & Bob’s senior cryptanalyst, said that transition efforts should begin now because changing the signature system could take years. The company believes advances in quantum hardware and reductions in the resources needed for an attack could converge in the early 2030s. Goudarzi also emphasized that the findings in the study are theoretical.
Not investment advice.