The long-anticipated quantum threat to Bitcoin has transitioned from a theoretical concern to a tangible reality.
On Friday, the quantum security startup Project Eleven announced that it had awarded its Q-Day Prize of 1 bitcoin to independent researcher Giancarlo Lelli. He successfully broke a 15-bit elliptic curve key using publicly accessible quantum hardware, effectively deriving a private encryption key from its public counterpart.
This prize is valued at approximately $78,000 based on current market rates and represents the most significant public demonstration of an attack method that could potentially jeopardize Bitcoin, Ethereum (ETH), and numerous other major blockchains.
Project Eleven Awards 1 BTC Q-Day Prize for Largest Quantum Attack on Elliptic Curve Cryptography to Date
Researcher breaks 15-bit ECC key on publicly accessible quantum hardware in a remarkable leap from previous demonstrations.
Project Eleven today awarded the Q-Day…
— Project Eleven (@projecteleven) April 24, 2026
Elliptic curve cryptography underpins the ability of crypto wallets to prove ownership of funds without disclosing their private keys. While public keys can be seen by anyone, deriving their corresponding private keys should theoretically be impossible in practical scenarios.
However, quantum computers utilizing Shor’s algorithm—a technique introduced in 1994—pose challenges by undermining the fundamental logic securing these signatures.
Lelli’s achievement does not imply that Bitcoin is on the verge of being compromised; it employs robust 256-bit elliptic curve security. In contrast, a mere 15-bit key offers only about 32,767 possible combinations—a minuscule figure when compared with Bitcoin’s security framework. The purpose behind this prize was to assess whether real-world attacks against cryptographic products are advancing beyond theoretical discussions into practical experiments using available technology.
The prior record for public breaches was set by Steve Tippeconnic in September 2025 when he demonstrated breaking a six-bit key with IBM’s advanced quantum computer featuring133 qubits. Lelli’s accomplishment marked an impressive increase by a factor of512 within just seven months.
A bit represents the smallest unit of information in classical computing; conversely, qubits serve as their counterparts within quantum computing frameworks.
Read more: A straightforward explanation regarding what quantum computing entails and why it poses significant risks for Bitcoin
Theoretical estimates concerning resource requirements have plummeted even more dramatically recently. A Google Research paper published last month suggested that executing an attack against full-scale256-bit encryption would require fewer than500,000 physical qubits—down significantly from earlier projections which estimated needs running into millions.
“The resource demands for this type of assault continue decreasing rapidly while making practical execution increasingly feasible,” stated Alex Pruden CEO at Project Eleven during discussions about these developments.
“It’s noteworthy that this successful submission originated from an independent researcher leveraging cloud-accessible resources rather than through national laboratories or proprietary chip designs.”
This issue becomes particularly pressing for wallets whose public keys are already exposed on-chain; accordingto estimates providedby Project Eleven around6.9 million bitcoins reside within such addresses—which constitutes roughly one-thirdof total supply—including Satoshi Nakamoto’s estimated one million bitcoins untouched since inception years ago.Any capablequantum computer ableto breach256-bitecc could leisurely sift through those wallets without hindrance .
A varietyof migration strategies have been proposedbyBitcoin developers including BIP-360,aBitcoin Improvement Proposal aimedat introducingquantum-safe address types.Ethereum ,Tron ,StarkWare,and Ripplehave also releasedpost-quantum transition plans .
While fifteen bits certainly do not equate two hundred fifty-six bits ,it signifies another milestonein growingconcernsfor bothbitcoin developersandthe wider community .
FAQ
- What is Quantum Computing?
- How does Quantum Computing threaten cryptocurrencies like Bitcoin?
- If my wallet’s public key is visible online now what should I do?
- What measures are being taken against potential future threats posed by Quantum Computers?
- This recent breakthrough seems alarming – how soon could we see actual attacks happening?