A quantum computer cracks a 15-digit ECC key; there is currently no threat to Bitcoin’s 256-bit security, but the migration countdown is accelerating

ME News, 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—marking the largest public demonstration of its kind to date, up 512 times from the 6-bit demonstration in September 2025. Lelli used a variant of Shor’s algorithm targeting the elliptic-curve discrete logarithm problem, which is the mathematical foundation of Bitcoin’s signature scheme. The awarded hardware has about 70 qubits. Currently, no known quantum computer 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 resource estimates for ECDLP-256 and set a target for migrating to post-quantum cryptography after 2029. Cloudflare followed suit immediately, and the UK NCSC also set migration milestones from 2028 to 2035. On-chain data shows that about 6.93 million BTC currently face potential quantum risk because their public keys have been exposed. The Bitcoin community has proposed BIP 360 and BIP 361 to push a migration to post-quantum-resistant output types, but coordinating upgrades across a decentralized network remains the biggest challenge. (Source: ChainCatcher)