Coinbase develops post-quantum Bitcoin custody safeguards

Coinbase is proactively developing security measures to protect the approximately $250 billion in digital assets it custodies from the potential threat of quantum computers. According to Yehuda Lindell, Coinbase's Head of Cryptography, the company is building safeguards that can adapt to various signature schemes Bitcoin might adopt in a post-quantum era.

Traditional Multi-Party Computation (MPC), a method for securing private keys by splitting them among multiple parties, may not be compatible with all post-quantum signature schemes, particularly hash-based signatures, which are considered more resistant to quantum attacks. This incompatibility poses a challenge for safeguarding digital assets.

To address this, Coinbase is exploring a fallback architecture that combines post-quantum threshold decryption with programmable Hardware Security Modules (HSMs). While keeping a complete key in one place, even within an HSM, is theoretically less secure than MPC, Lindell expressed confidence in the robust physical and code-upload controls of HSMs.

The company's strategy is to remain agnostic and adaptable to whatever signing scheme Bitcoin ultimately adopts, ensuring it can support diverse technical retooling in the future.