Coinbase Quantum Advisory Council Releases Bitcoin Quantum-Resistance Upgrade Recommendations, Urges Early Migration Preparation

October 13: The Coinbase Quantum Advisory Council released a position paper on quantum computing and blockchain, exploring the technical path for Bitcoin to address future quantum computing threats. Coinbase stated that Bitcoin's migration to a quantum-resistant system requires not only the selection of quantum-resistant digital signature schemes, but also consideration of block space constraints, full node verification capabilities, institutional custody needs, compatibility with ordinary wallets, and migration of existing assets. Coinbase currently custodies BTC representing approximately 5% of Bitcoin's total supply, and is advancing quantum-resistant preparations for its own systems, engaging in discussions with Bitcoin developers and researchers, and supporting related open-source research through engineering resources and participation in the Bitcoin Security Alliance. The paper is intended to provide a technical reference for community discussion and is not a final proposal or formal conclusion.

On the technical side, Coinbase recommends starting preparations before the quantum computing threat clearly arrives, because adjustments to Bitcoin's consensus rules and migration of the entire ecosystem may take years. The company believes that consideration should be given to output structures that can flexibly introduce, replace, or supplement different quantum-resistant signature algorithms, and to evaluate designs such as P2MR (BIP-360) and P2TRv2. At the same time, hybrid schemes running traditional signatures and quantum-resistant signatures in parallel could be studied, allowing users to migrate gradually before a final policy phasing out traditional signatures is determined. For the choice of signature algorithms, Coinbase recommends comprehensively comparing signature and key sizes, verification speed, side-channel protection, reliance on randomness, compatibility with hardware wallets and multi-party computation (MPC), security, and standardization progress, with key evaluation of ML-DSA, SLH-DSA, FN-DSA after future standardization, and other candidates including SHRINCS.

Coinbase also specifically cautions that although stateful quantum-resistant signatures may offer advantages such as smaller signature size and greater speed, improper state management could lead to state reuse and thus signature forgery risks. Therefore, stateless fallback options should be provided, and security management requirements for wallets and custody services should be clearly defined. In addition, for Bitcoin assets that have not yet migrated, whose keys are lost, or that are inaccessible, Coinbase believes they should be treated as a separate governance and engineering issue, with careful assessment of freezing, rate-limiting, rescue mechanisms, and the gradual retirement of traditional signatures, ensuring that the relevant measures themselves are quantum-resistant. Coinbase emphasizes that the migration process involves multiple trade-offs among block space, security, privacy, fees, and user asset accessibility, and the community should continue discussing how to handle existing assets while advancing work on quantum-resistant signature technology.