Project Eleven proposes Bitcoin wallet recovery tool for quantum attacks

Project Eleven has released a prototype cryptographic method aimed at a nightmare scenario for Bitcoin holders: proving a wallet is yours after a powerful quantum computer can fake its signatures. For retail investors, the issue is less about day-to-day Bitcoin use today and more about how the network could handle a future security break without leaving late movers stranded.

The security firm said Thursday that its post-quantum proof is designed to verify ownership of a Bitcoin wallet after so-called Q-Day. Q-Day is the hypothetical point when quantum computers become strong enough to break elliptic curve cryptography, the type of math Bitcoin uses to connect public keys, private keys and transaction signatures.

Today, a valid digital signature is treated as proof that someone controls the private key for a Bitcoin address. Project Eleven CEO Alex Pruden said on X that this assumption changes if a quantum computer can derive a private key from a public key. In that case, both the real owner and an attacker could create valid signatures for the same wallet, making the signature itself a poor test of ownership.

How the proposed proof works

Project Eleven’s proposal focuses on a wallet’s key derivation path. In plain terms, many crypto wallets generate individual private keys from a higher-level parent key, often tied to a seed phrase. A seed phrase is the set of recovery words a user stores to regain access to a wallet.

According to Project Eleven, its technique would let a user prove control of the parent key that produced a wallet’s private key without exposing that parent key. The company says a quantum attacker who has calculated the private key for a specific address would still lack the parent key or seed phrase behind it.

That distinction is the heart of the proposal. If an attacker can copy the signature but cannot prove knowledge of the parent key, the system could separate the legitimate owner from the attacker, Project Eleven said.

The method uses zero-knowledge proofs, a cryptographic approach that lets one party prove something is true without revealing the underlying secret. Project Eleven said the implementation was built with Jim Posen, lead maintainer of Binius, an open-source zero-knowledge proof system. The firm said Binius is designed to speed up cryptographic work involving many hash operations, which are one-way calculations used throughout blockchain systems.

Still a prototype, not a live Bitcoin feature

Pruden said the work builds on “signature lifting,” a method previously proposed by researchers Alon Sattath and Robert Wyborski. Project Eleven funded Posen to implement the approach using Binius, according to Pruden.

The company framed the tool as a recovery option for users who fail to move funds to quantum-safe addresses before any future migration. That matters because a network-wide shift to post-quantum security would likely require users to take action, and some wallets may remain exposed if owners miss the transition.

Project Eleven also cautioned that the prototype has not been audited. The company said it would need support at the blockchain protocol level before anyone could rely on it in practice. In other words, this is a proposed safety mechanism for a future threat, not a feature Bitcoin users can activate today.

The release comes as more crypto companies and researchers push for earlier preparation around quantum risk. Coinbase’s quantum advisory council has urged blockchain developers to start planning for post-quantum systems now, according to Decrypt.

This story draws on original reporting from Decrypt.