Project Eleven offers post-quantum proof for Bitcoin wallets

Project Eleven on Thursday unveiled a cryptographic proof intended to let Bitcoin users demonstrate ownership of wallets after quantum computers become able to forge signatures. The prototype was developed with Jim Posen, lead maintainer of the Binius zero-knowledge proof system, and remains unaudited. Project Eleven said the method would require changes at the blockchain protocol level or other network support before it could be used to move funds.

Project Eleven framed the problem as the loss of signature-based proof once elliptic curve cryptography can be broken. Project Eleven CEO Alex Pruden wrote on X: “How do you prove you still own a wallet after a quantum computer can forge its signatures?” The company says a quantum-equipped attacker could derive an address private key from a public key and produce valid signatures identical to those of the original owner.

The technique uses a wallet’s key derivation path. Instead of relying on a signature, a user would produce a proof that they control the parent key or seed from which a private key was derived, without revealing that parent key. Project Eleven says an attacker who can compute an address private key would still be unable to reconstruct the seed phrase or parent key, so proving knowledge of the parent key can distinguish the legitimate owner.

Project Eleven funded Posen to implement a form of “signature lifting” originally proposed by researchers Alon Sattath and Robert Wyborski, using the open-source Binius system. Binius is designed to speed hash-heavy zero-knowledge proofs. The company emphasized the prototype has not been audited and is not ready for protecting wallets on the live Bitcoin network.

Work on post-quantum resilience for Bitcoin is underway. A Bitcoin improvement proposal called BIP-360 advanced into formal review earlier this year. A separate group released a working implementation on a Bitcoin Quantum testnet to let developers trial potential upgrades. A quantum advisory council has urged developers to begin planning migrations and warned that roughly 7 million bitcoin could be at risk if owners do not move funds to quantum-resistant addresses. In June, U.S. executive orders directed federal agencies to speed the transition to post-quantum cryptography.

Pruden warned that some wallets will miss any migration window and that recovery methods will be needed. He wrote on X: “As much as I’d love for the entire world to take a quantum migration plan seriously, the reality is that some digital asset wallets will miss the window. This gives them a fallback: prove ownership through derivation, not signature, even after that window closes.”

Project Eleven said audited implementations, consensus decisions by developers and validators, and broad migration planning would be required for any recovery system to be adopted on Bitcoin.