Project Eleven has awarded its 1 Bitcoin (BTC) Q-Day Prize to independent researcher Giancarlo Lelli for breaking a 15-bit elliptic curve key on publicly accessible quantum hardware. This achievement, announced on April 24, 2026, represents the largest public demonstration of an attack class that threatens Bitcoin, Ethereum, and over $2.5 trillion in ECC-secured digital assets.
Lelli derived a private key from its public key across a search space of 32,767 using a variant of Shor's algorithm, which targets the Elliptic Curve Discrete Logarithm Problem (ECDLP) — the mathematical foundation securing most blockchains. The breakthrough extends the previous public record — a 6-bit demonstration by Steve Tippeconnic in September 2025 — by a factor of 512 in just seven months.
“The resource requirements for this type of attack keep dropping, and the barrier to running it in practice is dropping with them,” said Alex Pruden, CEO of Project Eleven. “The winning submission came from an independent researcher working on cloud-accessible hardware. No national lab, no private chip. It shows that tangible progress is possible and highlights the urgency to migrate to post-quantum cryptography sooner rather than later.”
Theoretical resource estimates for a full 256-bit attack have also fallen sharply. A Google Research whitepaper from April 2026 estimated the requirement at under 500,000 physical qubits, while a subsequent paper from Caltech and Oratomic suggested as few as 10,000 qubits in a neutral-atom architecture. Lelli's result is the practical counterpart to those optimizations.
Project Eleven estimates that roughly 6.9 million Bitcoin sit in wallets whose public keys are already visible on-chain, exposing them to potential quantum attack. Blockchain networks including Bitcoin, Ethereum, Tron, StarkWare, and Ripple have begun developing post-quantum transition plans, with Google committing to being quantum-secure by 2029.
