Circle warns quantum computing is closing in on blockchain security

[Wolfhound44]

Circle, the company behind the USDC stablecoin, published a technical monitoring tool showing that the theoretical threshold to break ECDSA signatures, the cryptography protecting most blockchain transactions, has dropped from 2,330 logical qubits in 2017 down to just 813 logical qubits as of August 2026. That's a 65 percent reduction in the computational resources theoretically needed to compromise the signature scheme most cryptocurrencies still rely on, driven partly by AI assisted circuit optimization improving how efficiently those attacks could theoretically be run

For context, Google's Willow processor has reached 105 logical qubits so far, while QuEra projects surpassing 1,000 logical qubits by 2029, meaning the gap is narrowing from both directions at once. Circle stressed this doesn't mean quantum computers can break blockchain signatures today, only that the distance between current capability and the theoretical threshold is shrinking faster than many expected. The company has already implemented support for SLH-DSA, a NIST standardized post quantum signature scheme, on its Arc network, while maintaining hybrid compatibility with existing ECDSA signatures during the transition

An estimated 14 million Bitcoin addresses have already revealed their public keys through past transactions, meaning a sufficiently capable quantum computer could theoretically recover the corresponding private keys, unlike a gradual classical security erosion, this specific vulnerability is often described as a potential cliff event rather than a slow decline. Curious what people think about crypto specifically needing to move faster on this than most people assume given how directly it's exposed

Circle Sounds the Alarm as Quantum Computing Narrows the Gap to Blockchain Security - Crypto Economycrypto-economy.com