A quantum computer can crack a 15-digit ECC key; Bitcoin’s 256-bit security is not yet under threat, but the migration countdown is speeding up

ME News — On April 25 (UTC+8), Project Eleven today awarded its Q-Day prize to researcher Giancarlo Lelli. Using publicly accessible quantum hardware, he successfully derived a 15-bit elliptic-curve private key from a public key—making it the largest public demonstration of its kind to date, 512 times greater than the six demonstration in September 2025. Lelli used a variant of Shor’s algorithm tailored to the elliptic-curve discrete logarithm problem, which is the mathematical foundation of the Bitcoin signature scheme. The awarded hardware has about 70 qubits. At present, there is no known quantum computer that can break real Bitcoin wallets, and Bitcoin’s 256-bit elliptic-curve security remains far beyond current quantum capabilities.

Of note, on March 31, Google lowered its ECDLP-256 resource estimates and set a target for migrating to post-quantum cryptography after 2029. Cloudflare followed suit, and the UK’s NCSC also set migration milestones from 2028 to 2035. On-chain data shows that currently about 6.93 million BTC are exposed to potential quantum risk due to public key exposure. The Bitcoin community has proposed BIP 360 and BIP 361 to promote a migration to quantum-resistant output types, but coordinating a decentralized network remains the biggest challenge. (Source: ChainCatcher)