Circle dropped a full post-quantum roadmap for @arc and frens, this is actually kind of a big deal. Most L1s are still treating quantum resistance like a "future problem." Arc is baking it in before mainnet. That's a rare move. Here's what the roadmap actually says: Phase 1 — ships at mainnet launch (2026): opt-in post-quantum wallet signatures using CRYSTALS-Dilithium (ML-DSA) and Falcon. Both NIST-finalized in August 2024. No forced migration. You choose when to upgrade. Phase 2 — private state protection. Quantum-resistant encryption for balances, confidential payments, recipient data. Not just wallets. The full private layer gets covered. Phase 3 — validator hardening. PQ signatures are 2-10x larger than ECDSA, so this phase waits for performance testing and tooling. Legit engineering caution, not delay for delay's sake. Phase 4 — offchain infrastructure. Cloud environments, HSMs, communication protocols, access controls. Full-stack, not just onchain. Why now? Google research said a powerful quantum computer could break Bitcoin's cryptography in ~9 minutes. Caltech researchers put the timeline at before 2030. "Harvest now, decrypt later" attacks are already live — someone can collect your signed transactions today and crack them when the hardware exists. Arc's sub-second finality actually helps here too. A 500ms block window leaves attackers almost nothing to work with on validator signatures. Well, the tradeoff is real — PQ signatures are bigger and heavier. Circle acknowledges it directly. But Bitcoin has no active PQ migration path. Ethereum is still at research stage. Arc is the only major L1 building this into architecture from day one. Goldman, Visa, Mastercard are already design partners on Arc. Institutional money doesn't tolerate "we'll figure it out later" on cryptographic security. The testnet is live. The roadmap is public. Mainnet comes in 2026. Also — @circle launched an onchain campaign connected to Arc ecosystem activity. If you haven't been active on testnet yet, now's a reasonable time to look at it. No promises, just real protocol activity. What's your read on PQ resistance as a moat for new L1s? Drop below.