Quantum computers cracking 15-digit ECC keys pose no threat to Bitcoin's 256-bit security, but the migration countdown is accelerating.

ME News report, April 25 (UTC+8): Project Eleven today awarded the Q-Day prize to researcher Giancarlo Lelli. Using publicly accessible quantum hardware, Lelli successfully derived a 15-bit elliptic curve private key from a public key—marking the largest public demonstration of its kind to date, with a 512-fold improvement over the 6-bit 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 Bitcoin’s signature scheme. The awarded hardware has approximately 70 qubits. At present, no known quantum computer can crack real Bitcoin wallets, and Bitcoin’s 256-bit elliptic curve security remains far beyond current quantum capabilities.

Of note, Google downgraded its resource estimate for ECDLP-256 on March 31 and set a migration target for quantum cryptography after 2029. Cloudflare subsequently followed, and the UK NCSC has also set migration milestones from 2028 to 2035. On-chain data shows that approximately 6.93 million BTC are at potential quantum risk because their public keys have been exposed. The Bitcoin community has proposed BIP 360 and BIP 361 to drive a migration to quantum-resistant output types, but coordination across decentralized networks remains the biggest challenge. (Source: ChainCatcher)