Quantum computers crack 15-digit ECC keys; Bitcoin’s 256-bit security poses no threat yet, but the migration countdown is accelerating

Deep Tide TechFlow news: On April 25, according to CryptoSlate, Project Eleven awarded the Q-Day prize to researcher Giancarlo Lelli on April 24. Lelli used publicly accessible quantum hardware to successfully derive a 15-digit elliptic curve private key from a public key, representing the largest publicly demonstrated scale of its kind to date—512 times greater than the 6-digit demonstration in September 2025. Lelli used a variant of Shor’s algorithm targeting the elliptic curve discrete logarithm problem, which is precisely the mathematical foundation of Bitcoin’s signature scheme. The awarded hardware had about 70 qubits.

At present, there is no known quantum computer capable of breaking 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 migration target for quantum cryptography after 2029. Cloudflare promptly 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 face potential quantum risk because their public keys have been exposed. The Bitcoin community has proposed BIP 360 and BIP 361, aiming to promote a migration to quantum-resistant output types, but coordinating a decentralized network remains the biggest challenge.