Researcher Achieves 15-Bit Quantum Break on ECC

An independent researcher has achieved the largest public demonstration of a quantum attack on elliptic curve cryptography, deriving a 15-bit private key from its public counterpart using a publicly accessible quantum computer, prompting renewed discussions on long-term cryptocurrency security.

Project Eleven, a startup focused on post-quantum threats, awarded Giancarlo Lelli one bitcoin, valued at approximately 77,736 dollars, for the breakthrough announced on Friday. Lelli completed the task in about 45 minutes by applying a variant of Shor's algorithm to solve the elliptic curve discrete logarithm problem, a core element of digital signatures in Bitcoin and Ethereum. The feat involved a search space of 32,768 possible private key combinations, marking a 512-fold increase over the previous public record of a 6-bit break set by Steve Tippeconnic in September 2025.

The demonstration utilized 27 physical qubits on cloud-based hardware, highlighting accelerating progress in accessible quantum experimentation. While the 15-bit scale remains trivial compared to the 256-bit keys securing major blockchains, it underscores the narrowing gap between theoretical risks and practical...