Google researchers found that future quantum computers could crack Bitcoin encryption in about nine minutes during transaction processing. The study estimated fewer than 500,000 qubits could break cryptographic protection, significantly lower than previous estimates. Attackers could derive private keys while transactions are pending, with a 41% probability of success before confirmation. The research also noted that around 6.9 million Bitcoin may already be vulnerable. Google emphasized the need for post-quantum cryptography as quantum computing advances.