Bitcoin’s biggest quantum risk may not be wallet keys. An early investor fears something bigger

Andrew Gault, the venture capitalist who funded the quantum hardware labs now threatening bitcoin, says the industry is looking in the wrong place. Google's own security team moved in the same direction in March. What to know : Security experts warn that the most urgent quantum threat to bitcoin and the broader financial system is not wallet keys but the encrypted authentication data already moving between institutions and being quietly harvested today. Adversaries are pursuing a “harvest now, decrypt later” strategy, stockpiling encrypted interbank messages, payment records and digital signatures to unlock once quantum computers become powerful enough, a risk Google and Citi have both begun modeling on aggressive timelines. While Ethereum has begun a coordinated post-quantum migration and Google is targeting 2029 for its own transition, Bitcoin and major crypto exchanges and custodians have yet to commit publicly to similar protections for their wire-level signing infrastructure.