Researcher Breaks 15-Bit Elliptic Curve Key Using Public Quantum Hardware, Wins 1 Bitcoin

• April 26, 2026

An independent cybersecurity researcher has successfully compromised a 15-bit elliptic curve cryptographic key using publicly accessible quantum computing equipment. The breakthrough marks a significant advancement in the practical demonstration of quantum attacks against cryptographic systems securing digital currencies such as bitcoin.

Quantum Computing Validates New Risks for Blockchain Security

The researcher, Giancarlo Lelli, achieved this milestone by leveraging open quantum computing infrastructure to decrypt a cryptographic key previously considered secure under classical methods. For this accomplishment, Lelli was awarded one bitcoin, valued at approximately $78,000, by the startup Project Eleven as part of their Q-Day Prize challenge. This accomplishment surpassed the prior public record for quantum key cracking by a factor of 512, establishing a new benchmark in the effectiveness of quantum-based cryptanalysis.

Elliptic curve cryptography (ECC) is widely employed across blockchain platforms and cryptocurrency wallets, making its security paramount for protecting digital assets. By demonstrating that even a relatively small 15-bit key can be broken on accessible quantum systems, this event underscores the growing threat quantum technologies pose to existing cryptographic standards.

The achievement signals a critical moment in the evolution of cybersecurity, emphasizing the need for the blockchain industry and security professionals to accelerate research into quantum-resistant encryption algorithms. While breaking larger keys remains a challenge due to hardware limitations, this demonstration offers a tangible preview of future quantum attack capabilities.

Project Eleven’s Q-Day Prize aims to foster innovation and real-world validation of quantum computing applications in cryptography. By incentivizing researchers to test quantum vulnerability claims on publicly available platforms, the initiative encourages transparency and advances understanding of quantum risks for encrypted systems.

This advancement is a pivotal reminder for sectors reliant on cryptographic protections to monitor developments in quantum computing closely and begin preparing strategies to mitigate emerging quantum threats. As quantum hardware continues to evolve, the intersection between quantum computing and cybersecurity will become increasingly significant for the sustainability of blockchain and other cryptographic technologies.

An independent researcher used public quantum computing resources to crack a 15-bit elliptic curve key and earned 1 bitcoin in a major quantum attack demonstration.