Security firm Project Eleven on Thursday unveiled a cryptographic technique designed to allow Bitcoin users to prove wallet ownership after quantum computers become capable of breaking current encryption methods. Project Eleven CEO Alex Pruden stated the central challenge is proving wallet ownership once quantum attacks become possible, as valid digital signatures will no longer reliably distinguish legitimate owners from attackers. The development comes as the cryptocurrency industry accelerates preparations for 'Q-Day'—the moment when quantum computers can break the elliptic curve cryptography securing Bitcoin transactions—with initiatives including Bitcoin Improvement Proposal BIP-360 advancing into formal review in February and Coinbase warning in June that approximately 7 million Bitcoin could become vulnerable if owners fail to migrate to quantum-safe addresses.
Project Eleven Introduces Key Derivation Path Verification Method
The 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. In a thread on X on Wednesday, Pruden explained that after Q-Day, both a quantum adversary and the legitimate owner can produce identical signatures once a quantum computer derives an elliptic curve cryptography private key from its public key. "Proving you know that parent key, without revealing it, is something only the real owner can do," Pruden wrote. According to Project Eleven, a quantum computer cannot reconstruct the parent key, enabling the technique to distinguish legitimate owners from attackers even after a wallet's private key has been compromised.
Jim Posen and Binius Implementation Build on Academic Research
The work was developed in collaboration with Jim Posen, lead maintainer of the open-source Binius zero-knowledge proof system. The implementation builds on a technique 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. The prototype is unaudited and would require blockchain protocol support before it could be used.
Bitcoin Developers Advance Quantum-Resistant Upgrades Through 2025
In February, Bitcoin developers advanced BIP-360 into the formal review process, laying the groundwork for future quantum-resistant upgrades. In March, BTQ Technologies released the first working implementation on its Bitcoin Quantum testnet, allowing developers to test the proposal. 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. Later that month, President Donald Trump signed executive orders speeding the federal government's transition to post-quantum cryptography.
Recovery Mechanism Targets Users Who Miss Migration Window
The proposed recovery mechanism is intended for users who miss a future migration to quantum-safe addresses. "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," Pruden wrote. "This gives them a fallback: prove ownership through derivation, not signature, even after that window closes."
FAQ
What did Project Eleven announce on Thursday?
Project Eleven unveiled a cryptographic technique that allows Bitcoin users to prove wallet ownership after quantum computers become capable of breaking current encryption methods. The technique uses a wallet's key derivation path to verify control of the parent key without revealing it.
Why does Bitcoin need post-quantum ownership verification?
After Q-Day, when quantum computers can derive private keys from public keys, valid digital signatures will no longer reliably prove wallet ownership because both attackers and legitimate owners can produce identical signatures. Project Eleven's technique addresses this by using the parent key from the derivation path, which quantum computers cannot reconstruct.
What quantum-resistant initiatives has the Bitcoin industry launched?
In February, Bitcoin developers advanced BIP-360 into formal review for quantum-resistant upgrades. In March, BTQ Technologies released the first working implementation on its Bitcoin Quantum testnet. In June, Coinbase warned that approximately 7 million Bitcoin could become vulnerable, and President Donald Trump signed executive orders accelerating the federal government's transition to post-quantum cryptography.
