Why the Path to Quantum Resistance Runs Uphill for Bitcoin Wallet Makers
Trezor CTO Tomáš Sušánka says post-quantum Bitcoin signatures could create new wallet security and usability challenges. SHRINCS offers compact stateful signatures, but reusing one-time keys can expose funds to theft; larger stateless signatures avoid that state-tracking risk. Trezor is considering making stateless signing the default while retaining stateful signing as an advanced option. Hardware wallets will also need post-quantum protections for firmware and device authentication, not just Bitcoin transaction signatures. Trezor says its Safe 7 supports post-quantum wallet authentication, though transactions will remain vulnerable until Bitcoin upgrades. Sušánka urges developers to provide migration options early, given the time needed for users to move to quantum-resistant systems.
