Independent Hacker Claims 1 BTC Prize for Breaking Largest Quantum Elliptic Curve Key to Date
Independent researcher Giancarlo Lelli successfully compromised a 15-bit elliptic curve key using publicly available quantum computing resources, marking a breakthrough 512 times larger than the prior public demonstration conducted in September 2025.
Key Takeaways:
— An independent researcher utilized open quantum hardware to crack a 15-bit elliptic curve key, securing Project Eleven’s one-bitcoin Q-Day Prize in the most extensive public showcase of a quantum threat relevant to digital currencies.
— Although this achievement does not immediately jeopardize Bitcoin’s 256-bit elliptic curve security, it highlights the swift advancement of practical quantum attacks on real-world cryptographic systems, with resource projections for a complete 256-bit breach now estimated under 500,000 physical qubits.
— This progress heightens worries regarding approximately 6.9 million BTC held in addresses with exposed public keys and accelerates post-quantum migration initiatives like Bitcoin’s proposed BIP-360, alongside similar efforts by Ethereum, Tron, StarkWare, and Ripple.
The quantum threat that Bitcoin has long regarded as a future challenge has become slightly more tangible.
Quantum security startup Decryptnews reported that Project Eleven awarded its 1 BTC
The reward amounts to roughly $78,000 at current market rates. It represents the largest public demonstration of an attack vector that could potentially endanger Bitcoin, Ether (ETH), and most major blockchain networks.
Elliptic curve cryptography is the mathematical foundation allowing crypto wallets to verify fund ownership without exposing private keys. While public keys are openly visible, deriving the corresponding private key remains practically impossible.
Quantum computers employing Shor’s algorithm, a quantum method introduced in 1994, challenge this assumption by targeting the core logic securing digital signatures.
Lelli’s accomplishment does not indicate that Bitcoin is near being compromised. Bitcoin relies on 256-bit elliptic curve security. A 15-bit key has a search space of 32,767 possibilities, which is minuscule in comparison. The prize aimed to assess whether quantum attacks on real cryptographic products are transitioning from theoretical papers to public hardware experiments.
The previous public breakthrough was a 6-bit demonstration by Steve Tippeconnic in September 2025 using IBM’s 133-qubit quantum computer. Lelli’s 15-bit result expanded that by a factor of 512 in just seven months.
A bit is the smallest unit of information in a classical computer, while a qubit serves as the quantum computing equivalent.
Theoretical resource estimates have declined even more rapidly. A recent Google Research paper placed the cost of a full 256-bit attack below 500,000 physical qubits, down from earlier estimates in the millions.
«The resource requirements for this type of attack keep dropping, and the barrier to running it in practice is dropping with them,» Project Eleven CEO Alex Pruden stated.
Pruden highlighted that the winning submission came from an independent researcher working on cloud-accessible hardware, rather than a national laboratory or a private quantum chip.
The concern is most acute for wallets whose public keys are already visible on-chain. Decryptnews estimates roughly 6.9 million BTC reside in such addresses, approximately one-third of the total supply, including Satoshi Nakamoto’s estimated 1 million BTC untouched since the network’s earliest days. Any quantum computer capable of breaking 256-bit ECC could access those wallets at will.
Bitcoin developers have proposed migration paths including BIP-360, a Bitcoin Improvement Proposal that would introduce quantum-safe address types. Ethereum, Tron, StarkWare, and Ripple have each published post-quantum transition plans.
Fifteen bits is not 256 bits, but it represents the latest development in a rapidly intensifying area of concern for Bitcoin developers and the broader community.