What Happened to QDay Prize?

The QDay Prize was established by Project Eleven (P11), a quantum computing research organization, on April 16, 2025, with the explicit goal of accelerating the understanding and mitigation of the quantum threat to modern cryptography. The competition offered a bounty of 1 Bitcoin to any individual or team capable of demonstrating a successful break of an Elliptic Curve Cryptography (ECC) key using Shor's algorithm on a quantum computer, without relying on classical shortcuts or hybrid methods. The deadline for submissions was set for April 5, 2026.

The motivation behind the QDay Prize stemmed from the rapid advancements in quantum computing and the theoretical vulnerability of widely used cryptographic schemes, such as ECC, to Shor's algorithm. ECC underpins the security of digital assets like Bitcoin and Ethereum, and a successful large-scale quantum attack could compromise trillions of dollars in value. Project Eleven aimed to foster transparency, stress-test existing cryptographic standards, and provide a clear benchmark for quantum performance in cryptanalysis.

A significant turning point occurred in September 2025 when Steve Tippeconnic achieved the first public 6-bit ECC key break on quantum hardware. This was followed by the prize being awarded on April 24, 2026, to independent Italian researcher Giancarlo Lelli, who successfully derived a private key from a 15-bit ECC public key using a variant of Shor's algorithm on a publicly accessible quantum computer. This represented a 512x jump in complexity from Tippeconnic's earlier demonstration and involved a search space of 32,767 possible values. Project Eleven hailed this as the largest public demonstration to date of the attack class threatening ECC-secured digital assets.

However, the significance of Lelli's achievement immediately became a subject of debate. Craig Gidney, a research scientist on Google's quantum computing team, published a critique on April 25, 2026, arguing that the competition's premise was flawed. Gidney contended that Shor's algorithm, for cryptographically relevant instances, requires robust quantum error correction, which current quantum computers largely lack. He suggested that the 15-bit break might not represent meaningful progress towards a practical quantum attack and could even be indistinguishable from a random guess, potentially measuring something irrelevant. Project Eleven, while acknowledging the lack of full error correction, defended the submission as a legitimate demonstration of the attack class on real, publicly accessible hardware, highlighting the dropping resource requirements for such attacks and the urgency for post-quantum cryptography migration.

As of April 28, 2026, the QDay Prize has concluded with the award to Lelli. The event has successfully brought increased attention to the quantum threat and the ongoing race to develop post-quantum cryptographic solutions. While the immediate danger to 256-bit ECC keys (used by Bitcoin) remains distant, the rapid progress in quantum hardware and theoretical resource estimates (e.g., Google's April 2026 whitepaper estimating under 500,000 physical qubits for a 256-bit attack, and Caltech/Oratomic suggesting as low as 10,000 qubits) underscore the urgency. Project Eleven is reportedly developing its next challenge, focusing on the intersection of frontier AI models and quantum cryptanalysis, indicating a continued commitment to advancing research in this critical field.