Bitcoin Post-Quantum Migration Will Require Broad Participation, Project Eleven CEO Says

Bitcoin developers should move from research into production on a post-quantum signature scheme rather than continue waiting for greater certainty about quantum-computing timelines, Project Eleven CEO Alex Pruden said at CoinDesk’s Consensus Miami conference on Wednesday.

Pruden said the asymmetry between acting now and waiting favors early action. He described the worst case of moving early as adding new cryptography that turns out not to be needed immediately but remains available as an option. In contrast, he said the worst case of moving late would allow a sufficiently capable quantum computer to derive private keys from any exposed public key using Shor’s algorithm.

Pruden valued the asset at stake at roughly $2.3 trillion. "In a very real sense, someone with a sufficiently large and capable quantum computer kind of owns everyone’s digital assets or bitcoin for the public key that they can see," Pruden said. The path forward involves introducing a new signature scheme into Bitcoin that does not rely on the classical math underlying the elliptic-curve digital signature algorithm, or ECDSA, currently in use.

The National Institute of Standards and Technology has standardized post-quantum schemes based on hash functions and lattices. Bitcoin community discussion has trended toward the hash-based option. BIP-360, proposed last year, laid groundwork for adding a quantum-resistant Taproot output type.

Blockstream has deployed a hash-based signature scheme on its Liquid Network.

Pruden said the migration will be substantially harder than the Taproot upgrade, which took roughly five years. Taproot remained opt-in and most users never participated. In a post-quantum migration, every bitcoin holder, wallet, exchange and institution that touches the asset will need to participate to stay secure.