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.

He said the timing risk is severe. If a quantum computer arrives before users have migrated, an attacker could front-run pending transactions within a single block time by paying a higher fee to capture funds whose private keys it has derived. Pruden urged the community to focus first on the migration itself and defer debate over what to do with bitcoin sitting in dormant, quantum-vulnerable addresses.

Harper framed that debate as involving upward of 5 million dormant coins, including coins attributed to Satoshi Nakamoto via the so-called “Patoshi” pattern of early miner blocks.

Pruden said the question of the Satoshi coins in particular is difficult because it places Bitcoin’s fixed-supply commitment in tension with its commitment to digital property rights. Asked for his personal view, he said recycling dormant quantum-vulnerable coins back into the supply curve would put him overall on the confiscation side, though he stressed the community and market would ultimately decide.

On whether Bitcoin Core developers are taking the threat seriously, Pruden said the answer is mixed. He noted that Core is not a monolithic entity. Some developers take the threat seriously while others believe quantum computers will never arrive. Pruden pointed to the broader scientific community, saying the majority of physicists believe quantum computers will become a reality and that many see timelines accelerating.

He added that the same physics underlying the threat may also lead to new cryptographic primitives, citing key-exchange protocols based on quantum entanglement.

“Moving stuff out of just research into production is, I think, actually what we need to focus on. Let’s focus on the D of R&D.”