A group of researchers from several European laboratories and companies specializing in quantum computing calculated the parameters of a quantum computer needed to guess the private key from the 256-bit elliptic curve public key (ECDSA) used in the Bitcoin cryptocurrency. The calculation showed that hacking Bitcoin using quantum computers for at least the next 10 years is not realistic.
In particular, it takes 256 × 317 physical qubits to try and guess a 106-bit ECDSA key within an hour. Public keys in Bitcoin can only be attacked within 10-60 minutes after the initiation of a transaction, but even if it could take longer to crack, the order of magnitude of the power of a quantum computer remains at the same level with increasing time. For example, fitting during a day requires 13 × 106 physical qubits, and 7 days requires 5 × 106 physical qubits. For comparison, the most powerful quantum computer currently created has 127 physical qubits.
Source: opennet.ru