LARGEST QUANTUM ATTACK ON ELLIPTIC CURVE CRYPTOGRAPHY TO DATE

Project Eleven awarded its 1 BTC “Q-Day Prize” to Giancarlo Lelli for breaking a 15-bit elliptic curve key on a public quantum computer, the largest real-world demonstration yet of an attack class that could threaten ECC-based systems.

The attack used a variant of Shor’s algorithm to solve the elliptic curve discrete logarithm problem, the cryptographic foundation behind Bitcoin.

This builds on a 6-bit quantum break in 2025 and represents a 512x increase in complexity.

While still far from Bitcoin’s 256-bit security, researchers say the gap is increasingly an engineering challenge, not a theoretical one.

Estimates for breaking full-scale keys have dropped sharply, with recent studies suggesting it could require as few as 10,000 to 500,000 qubits.

Roughly 6.9M BTC sit in wallets with exposed public keys, making them theoretically vulnerable if quantum capabilities scale.

Experts stress this does not pose an immediate threat to Bitcoin today, but underscores growing urgency around post-quantum cryptography.