Summary
- Project Eleven has unveiled a post-quantum proof designed to verify Bitcoin wallet ownership after the advent of quantum computing.
- This technique was developed alongside Binius maintainer Jim Posen and is based on prior academic work.
- The prototype remains unaudited and would need support from blockchain protocols for practical use.
With rising worries regarding Bitcoin's security against quantum threats, Project Eleven introduced a cryptographic solution on Thursday aimed at enabling users to demonstrate their ownership of a wallet even after quantum computers become capable of deriving private keys and generating valid digital signatures.
In a recent discussion on X, Project Eleven's CEO Alex Pruden emphasized that the primary issue is not about shielding wallets from quantum attacks but rather proving ownership once such attacks become a reality.
“How do you prove you still own a wallet after a quantum computer can forge its signatures?” Pruden questioned. “After Q-Day, when a quantum computer can derive an ECC private key from its public key, a valid signature no longer confirms ownership. Both the quantum attacker and the rightful owner can produce identical signatures.”
The term "Q-Day" refers to the moment when a quantum computer can successfully break the elliptic curve cryptography that secures Bitcoin transactions. The industry fears that this capability could allow attackers to derive private keys from public keys, rendering digital signatures unreliable for confirming wallet ownership.
This vulnerability means attackers could compromise wallets, forge signatures, and transfer Bitcoin without the owner's consent.
Project Eleven's approach utilizes a wallet's key derivation path, permitting users to verify control of the parent key that generates a wallet's private key without exposing it.
Since a quantum computer cannot reconstruct the parent key, the company claims it can distinguish between a legitimate owner and an attacker, even if a wallet's private key is compromised.
“So even after Q-Day, an attacker who has accessed your address's private key does not possess, nor can they compute, the seed phrase it was derived from. Proving you know that parent key, without revealing it, is something only the genuine owner can achieve,” Pruden stated.
This initiative was developed in partnership with Jim Posen, the lead maintainer of the open-source Binius zero-knowledge proof system, building upon a concept known as "signature lifting," initially proposed by researchers Alon Sattath and Robert Wyborski. Project Eleven has funded Posen to implement this method using Binius, an open-source proof system aimed at enhancing hash-heavy cryptographic operations.
The proposed recovery method is designed for users who may miss future migrations to quantum-resistant addresses, coinciding with the increasing efforts to prepare Bitcoin for a post-quantum environment.
In February, Bitcoin developers moved BIP-360, a Bitcoin improvement proposal, into formal review, setting the stage for future quantum-resistant upgrades. In March, BTQ Technologies launched the first operational version on its Bitcoin Quantum testnet, allowing developers to assess the proposal while underlining the difficulties of achieving consensus for a network-wide upgrade.
In June, Coinbase's quantum advisory council urged blockchain developers to initiate plans for post-quantum migrations, warning that about 7 million Bitcoin could be at risk of quantum attacks if owners do not transfer funds to quantum-safe addresses. Later that month, President Donald Trump signed executive orders to expedite the federal government's shift to post-quantum cryptography, further propelling efforts to prepare for Q-Day.
“While I wish for the entire world to take quantum migration plans seriously, the reality is that some digital asset wallets will miss the opportunity,” Pruden remarked. “This provides them a backup: to prove ownership through derivation rather than signature, even after that opportunity has passed.”