Circle's recent quantum strategy is quite solid, with SLH-DSA and ECDSA running in parallel, and a clear transition plan.

According to Crypto界, Wu Shuo learned that the arc official post said that Circle has published a post-quantum security white paper, proposing a phased security roadmap for arc, USDC, smart contracts, validators, and infrastructure systems. The white paper points out that quantum computing may pose long-term risks to blockchain signatures, validator keys, smart contracts, and network communications. Circle plans to support SLH-DSA signature verification in arc and, during the transition period, allow USDC smart contracts to continue supporting ECDSA interaction while enabling post-quantum signatures. Circle said that the final cutover timeline will depend on ecosystem readiness, regulatory requirements, and quantum risk assessments, and the related roadmap may still be adjusted.