Crypto researchers cut Bitcoin and Ethereum quantum attack estimate by 50%

Quantum computing’s threat to blockchain security just moved significantly closer. A new research paper reveals that a collaborative push by human researchers and AI agents has optimized a crucial sub-routine of Shor’s algorithm, effectively halving the estimated computational overhead required to crack the cryptographic foundations of Bitcoin and Ethereum. By outperforming landmark benchmarks established by Google in March, the study dramatically accelerates the theoretical timeline for when quantum hardware could compromise ECDSA (Elliptic Curve Digital Signature Algorithm)—the mathematical bedrock securing public-key cryptography across major networks. The breakthrough centers on drastically reducing the circuit depth and logical qubit count needed for modular exponentiation, the most resource-intensive phase of Shor’s algorithm. Previously, cracking a 256-bit elliptic curve key was widely estimated to require millions of noisy physical qubits, placing a practical attack decades into the future. However, by deploying AI agents to discover novel, highly compressed circuit architectures, the researchers demonstrated that the threshold for an exploit is roughly 50% lower than Google’s spring calculations suggested. This proves that algorithmic optimization, accelerated by machine learning, can erode cryptographic security margins far faster than hardware advancements alone. For protocol developers, these findings elevate quantum resistance from a long-horizon research topic to an urgent engineering constraint. Ethereum is relatively well-positioned to adapt; its ongoing roadmap already integrates post-quantum primitives via account abstraction, allowing smart contract wallets to swap out vulnerable signature schemes for lattice-based alternatives. Bitcoin faces a far more complex hurdle. Upgrading the network’s base layer to quantum-resistant standards will require a contentious network upgrade. More critically, early legacy addresses—including the estimated 1.1 million BTC held in Satoshi Nakamoto’s untouched wallets—expose public keys directly on-chain, rendering them prime targets unless moved to modern output types before quantum capabilities mature. For institutional investors and risk desks, the paper serves as a sharp reminder that blockchain security is a moving target. While macro tailwinds and spot ETF flows dictate near-term price action, long-term capital must now factor in a compressed quantum runway. Networks that proactively implement post-quantum cryptography will likely command a structural risk premium, whereas protocols stymied by governance inertia risk severe existential discounting. The quantum threat is no longer purely a hardware race; software and AI have officially accelerated the clock.