Project Eleven Proposes Post-Quantum Proof to Verify Bitcoin Ownership After Q-Day Attack

According to Decrypt, security firm Project Eleven unveiled a post-quantum cryptography proof mechanism today (July 17) designed to help Bitcoin users prove wallet ownership after quantum computers break private keys—an event known as Q-Day. Project Eleven CEO Alex Pruden explained the core challenge is not preventing quantum attacks, but proving ownership afterward; once a quantum computer can derive private keys from public keys, valid digital signatures no longer prove ownership, as both attackers and legitimate holders can generate identical signatures.

The technology leverages wallet key derivation paths, allowing users to prove they hold the parent key that generated wallet private keys without exposing those keys themselves. Since quantum computers cannot reconstruct parent keys, legitimate holders can be distinguished from attackers even after wallet private keys are compromised. The solution was developed in collaboration with Binius maintainer Jim Posen and is based on signature lifting techniques proposed by researchers Alon Sattath and Robert Wyborski.