Bitcoin’s Taproot could make quantum attacks easier than expected, new Google research says

Google’s Quantum AI team has published research indicating that breaking Bitcoin’s security with quantum computers may require significantly fewer qubits than previously estimated – potentially less than 500,000. This challenges the assumption that quantum threats are decades away. The research details two potential attack methods requiring 1,200-1,450 high-quality qubits, and explains how attackers could steal bitcoin mid-transaction by exploiting the brief exposure of public keys. Bitcoin’s 2021 Taproot upgrade, while improving privacy and efficiency, is identified as a contributing factor, as it makes public keys visible on the blockchain by default. Approximately one-third of all Bitcoin (6.9 million) is estimated to be in vulnerable wallets. Google is employing zero-knowledge proofs to share its findings responsibly, proving accuracy without revealing attack methods. The key takeaway is that the timeline for quantum threats to Bitcoin may be shorter and the risks broader than previously understood.

(Source：CoinDesk)