Google's Quantum AI team has published a paper warning about how quickly existing cryptographic mechanisms, including Bitcoin, could be broken by quantum computers. Google claims that through quantum circuit optimization, the number of qubits required to solve the elliptic curve discrete logarithm problem has been reduced to one-twentieth (500,000). They stated that a Bitcoin private key could be breached in 9 minutes—faster than block generation time—and that the top 1,000 Ethereum wallets could be compromised within 9 days. They mentioned that they would not disclose details about the quantum circuits themselves in the paper because they are dangerous. Of course, a 500,000-qubit quantum computer does not currently exist. Since current prototypes are around 1,000 qubits, it is correct to assume there is still time. However, given the rapid pace of technological advancement these days, it seems they are sending the message that a breach could actually occur within three years (as they explicitly mentioned), and that migration must be undertaken within that timeframe. research.google/blog/safeguard...