Quantum computers unlikely to break Bitcoin by 2026, experts say, but early preparation urged

Specialists told Cointelegraph on Dec. 25 that quantum computing poses a largely theoretical rather than imminent threat to cryptocurrencies in 2026, with Argentum AI's Clark Alexander expecting extremely limited commercial quantum use by then and Coin Bureau co-founder Nic Puckrin estimating at least another decade before machines can break current cryptography. Bitcoin and other blockchains rely on public-key cryptography with potential vulnerabilities, as Boosty Labs' Sofiia Kireieva cited the Elliptic Curve Digital Signature Algorithm as the weakest link compared with SHA-256, while O Foundation founder Ahmad Shadid warned that address reuse sharply increases exposure, with about 25% to 30% of BTC—roughly 4 million coins—already held in addresses whose public keys are visible and thus more susceptible to future quantum attacks. Sahara AI co-founder Sean Ren cautioned that the realistic 2026 risk is adversaries harvesting encrypted data for later decryption, a "collect now, decrypt later" approach described by Cysic co-founder Leo Fan, and the market has begun responding, as Qastle said in November it plans to upgrade cryptography to offer quantum-grade protection for hot wallets, while experts recommend avoiding address reuse and moving funds to quantum-resistant wallets once available.