Project Eleven proposes quantum-resistant Bitcoin recovery using key derivation proof
In brief
- Project Eleven uses wallet key derivation to prove ownership after Q-Day without revealing private keys
- Quantum computers cannot reconstruct parent keys, distinguishing legitimate owners from attackers
- Developed with Jim Posen, Binius zero-knowledge proof maintainer, building on signature lifting research
The ownership problem after Q-Day
Project Eleven CEO Alex Pruden stated that the central challenge after Q-Day is proving who owns a wallet, not protecting wallets from quantum attacks. After a quantum computer derives an ECC private key from its public key, a valid signature no longer proves ownership. Both the quantum adversary and the legitimate owner can produce identical signatures.
This distinction matters because it means traditional signature-based recovery fails. The entire proof-of-ownership model collapses when the attacker's cryptographic capability matches the owner's.
How key derivation proves ownership
Project Eleven's technique uses a wallet's key derivation path to allow users to prove they control the parent key used to generate a wallet's private key without revealing it. A quantum computer cannot reconstruct the parent key, allowing the technique to distinguish a legitimate owner from an attacker even after a wallet's private key has been compromised.
The work was developed in collaboration with Jim Posen, lead maintainer of the open-source Binius zero-knowledge proof system. The technique builds on a method known as signature lifting, first proposed by researchers Alon Sattath and Robert Wyborski. Project Eleven funded Posen to implement the approach using Binius, an open-source proof system designed to accelerate hash-heavy cryptographic operations.
Broader quantum migration timeline
The proposed recovery mechanism is intended for users who miss a future migration to quantum-safe addresses. In February, Bitcoin developers advanced BIP-360, a Bitcoin improvement proposal, into the formal review process. In March, BTQ Technologies released the first working implementation on its Bitcoin Quantum testnet.
The urgency has grown. In June, Coinbase's quantum advisory council urged blockchain developers to begin planning post-quantum migrations, warning that roughly 7 million Bitcoin could eventually be vulnerable to quantum attacks if owners fail to move funds to quantum-safe addresses. That same month, President Donald Trump signed executive orders speeding the federal government's transition to post-quantum cryptography.
Project Eleven's recovery approach serves as a fallback for wallets that don't migrate in time.
