Security firm Project Eleven introduced a cryptographic technique to prove Bitcoin wallet ownership after "Q-Day," when quantum computers can forge signatures. The method uses a wallet's key derivation path, distinguishing legitimate owners from attackers, addressing growing concerns about quantum attacks on Bitcoin's security.
Giancarlo Lelli won one Bitcoin from Project Eleven's Q-Day Prize on Apr. 24 for deriving a 15-bit elliptic curve private key from its public key using publicly accessible quantum hardware — the largest demonstration of this attack class that could threaten Bitcoin and Ethereum. While a 15-bit key is nowhere near Bitcoin's 256-bit security, Google cut ECDLP-256 resource estimates 20-fold in March and set a 2029 migration deadline, with Cloudflare matching that target.
Project Eleven awarded 1 BTC to an Italian researcher after a public quantum computer breaks a 15-bit elliptic curve key, the largest public demonstration of its kind to date.
