Quantum computing risk shifts from BTC wallets to exchange and custody infrastructure

Andrew Gault, CEO of ZeroTier, says the biggest threat from quantum computing is more systemic than “wallet cracking.” Instead of immediately breaking BTC’s wallet cryptography (secp256k1), the long-term exposure may sit in the authentication and signing systems that run banks, exchanges, custodians, bridges, and DeFi. The core concern is “Harvest Now, Decrypt Later” (HNDL). Attackers can capture and store encrypted transaction data, authentication messages, and signatures today. With future quantum computing capability, those recorded items could be decrypted or abused retroactively, turning current traffic into a long-lived liability. Gault and related reporting note that many systems still rely on cryptographic primitives such as ECDSA and RSA. That raises the possibility of forged signatures and operational failures—especially in cross-chain bridges and institutional workflows (e.g., stolen API keys for trading bots). While a migration to post-quantum cryptography is expected to be gradual and guidance exists (e.g., NIST post-quantum efforts), major exchanges/custodians have not always provided clear timelines. Traders should treat this as an upgrade/compliance and risk-pricing issue rather than an imminent BTC wallet breach, which may influence sentiment around infrastructure-heavy venues over time.