Coinbase has published a technical paper calling on Bitcoin developers to begin preparing for quantum computers now, rather than waiting until a machine capable of breaking today's signatures actually exists.
The paper, released on October 13, argues that moving Bitcoin to quantum-resistant cryptography will take years. New output types and signature schemes have to be designed, reviewed, activated by the network and then adopted by wallets, exchanges and custodians, and every coin that needs protecting has to be physically moved to a new address. Starting that process late, Coinbase warns, would leave too little time to finish it.
The exchange has a direct stake in the outcome. It is one of the largest bitcoin custodians in the world, holding coins on behalf of banks, asset managers and hedge funds (CoinDesk puts its share at roughly 5% of all bitcoin), and it says it is already re-engineering its own key-management systems for a post-quantum future.
Flexibility over a single fix
Rather than backing one specific algorithm, Coinbase's main request is flexibility. It points to BIP-360 (Pay-to-Merkle-Root, or P2MR) and a proposed P2TRv2 output type as promising designs because they would let Bitcoin add quantum-resistant signature schemes over time without a new overhaul for each one.
The paper also favours hybrid wallets. Users would keep spending with today's elliptic-curve signatures but also commit to a backup, quantum-proof key in advance. If quantum computers ever become a real threat, that backup path could be switched on without forcing everyone to scramble at once.
Built for custodians, too
Much of the post-quantum debate so far has focused on individual users. Coinbase stresses that large custodians have extra needs. It asks that at least one of the post-quantum schemes Bitcoin adopts be practical for multi-party computation (MPC) signing, the technique Coinbase and many institutions use to split control of a key across several machines so no single device ever holds it.
Earlier this year, Coinbase's security chief Jeff Lunglhofer said the company was building PQ-CoreKMS, a post-quantum version of the MPC key-management system that protects almost all of the assets it holds. Coinbase also says it is supporting open-source research and taking part in the Bitcoin Security Consortium.
The lost-coin question
Coinbase deliberately treats one issue as a separate debate: what to do with old coins whose public keys are already visible on the blockchain and whose owners may never move them, including the early coins widely attributed to Satoshi Nakamoto.
That question came into sharper focus days later. On October 15, nine blockchain organisations launched a group called the Quantum Alliance to work on shared post-quantum security standards. The alliance estimates that around 6.4 million BTC, about 30% of the supply, sits in addresses with exposed public keys, including roughly 1.1 million BTC attributed to Satoshi. No existing quantum computer can derive private keys from those public keys, but members of the alliance openly disagree on whether vulnerable coins should eventually be frozen or left for owners to migrate.
Why it matters
Any change to Bitcoin's signature rules would need a soft fork, and Bitcoin has not activated one since Taproot in 2021. Having a custodian of Coinbase's size publicly push for an early, flexible start adds institutional weight to proposals like BIP-360, though the final call still rests with node operators, miners and developers. For ordinary holders, the practical advice for now stays the same: avoid reusing addresses, since coins whose public key has never been revealed are far harder for a future quantum attacker to target.
19 October 2026
Country:
Global
Topic:
Cryptography | Security