A group called Project Eleven has proposed a new cryptographic proof designed to help Bitcoin users recover their wallets after a quantum attack — the so-called Q-Day event many in the industry have been bracing for. The 'Bitcoin Q-Day Recovery Proposal' would let users prove ownership of their Bitcoin without needing to expose the pre-quantum private keys, which could be compromised by a sufficiently powerful quantum computer.
What the proposal does
The recovery mechanism is built around a post-quantum cryptographic proof. Instead of relying on the current elliptic-curve signatures that a quantum machine could crack, the proposal gives users a way to demonstrate they controlled a wallet before the attack. The idea is that even if the old keys are broken, the owner can still move their coins to a new, quantum-resistant address.
Why Q-Day matters
Quantum computers capable of breaking Bitcoin's encryption aren't here yet — but researchers have been warning for years that the day is coming. When it does, any wallet that has ever broadcast a public key could be vulnerable. That's a lot of coins. The Bitcoin community has been slow to adopt quantum-resistant signatures, partly because of the complexity of a hard fork or a soft fork upgrade. Project Eleven's proposal tries to solve a different problem: recovery after the fact, rather than prevention beforehand.
How the proof works
The details are technical, but the core idea is a zero-knowledge-style proof that uses post-quantum cryptography. A user would generate a new quantum-safe key pair before the attack, then prove that the old address belonged to them without revealing the old private key. The proposal doesn't require changes to Bitcoin's consensus rules — it works as a layer on top, using transaction scripts and off-chain proofs. That means it could be deployed without a network-wide upgrade, at least in theory.
Project Eleven has released the proposal as a draft for discussion. It's not a formal Bitcoin Improvement Proposal yet, but the group is asking for feedback from cryptographers and developers. No timeline has been set for implementation. The bigger question — whether the broader Bitcoin ecosystem will rally behind a recovery solution before a real quantum threat materializes — is still open. For now, this is a plan on paper, not a patch on the network.
