q-day prize

Researcher Wins Bitcoin Prize for Quantum Attack Breaking 15-bit Crypto Key

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.