Coinbase Designs Quantum-Resistant Custody for $250B in Assets

Coinbase is developing post-quantum custody safeguards for approximately $250 billion in assets held on behalf of institutional clients including BlackRock, according to Yehuda Lindell, the exchange's head of cryptography. Lindell said on MARA Foundation TV that Coinbase's architecture will be signing-scheme agnostic, as it remains unclear which post-quantum standard Bitcoin will adopt. "It's unlikely that there will be a single signing scheme that everybody will use," he said. The concern centers on Multi-Party Computation (MPC), which splits private keys across parties to eliminate single points of failure. Hash-based post-quantum signatures may lack the arithmetic structure MPC requires, potentially rendering it unusable. As a fallback, Coinbase is researching Hardware Security Modules (HSMs) that would encrypt keys with post-quantum cryptography and assemble them only inside physically secured data centers. Lindell said the timeline remains uncertain but that the finished system will support any blockchain's chosen scheme.