Circle outlines post-quantum security roadmap for Arc layer-1 ahead of 2026 mainnet

Circle has published a post-quantum security roadmap for its layer-1 blockchain Arc, detailing a phased rollout that begins with opt-in quantum-resistant wallets and signatures at mainnet launch, which the company expects sometime in 2026. The plan later extends to validator-level protections and offchain infrastructure, alongside a privacy-focused quantum solution introduced after mainnet. Arc is already running on a public testnet and is positioned around enterprise use cases involving USDC.