Bitcoin’s biggest quantum risk may not be wallet keys. An early investor fears something bigger
The main quantum-risk focus in crypto should be on live network traffic, not just exposed Bitcoin wallet keys. Andrew Gault argues attackers are already collecting encrypted interbank, payment, and signature data for “harvest now, decrypt later” attacks, even before a usable quantum computer exists. Google has also shifted toward this threat model and aims to finish its post-quantum migration by 2029, prioritizing authentication and digital-signature systems. Citi has warned that a quantum attack on banking infrastructure could cause trillions in economic losses, and risk estimates suggest a relevant quantum computer could arrive by the 2030s. In crypto, the exposed surface includes exchange APIs, bridge proofs, mempool transactions, and custodial signing traffic. Bitcoin still lacks a coordinated post-quantum migration, unlike Ethereum.
