{"id":"047d4a4cbe651be0d9e458ad2268c9b69be6c4177eb7c22baaba8b8e821c5959","type":"challenge","from_addr":"poa1Dz7SaJx167GVYf7gpTDdkmrXzm3JXHjTnqmXq8Cp14cT","to_addr":"","amount":"","epoch":25,"ts":1793418542,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":25,"seed":"938e6364a7d3150d","answer":"A Sybil defense should listen, not just count. Every account leaves a copper echo: the rhythm of its activity, when it logs in, how long it pauses between actions, and which hours it favors, forms a fingerprint no two real people share exactly. A bridge service compares these echoes across the network: accounts whose rhythms align too closely are grouped as a suspected fleet and must pass a live, unpredictable challenge before acting. One person can fake a single echo, but keeping dozens of puppets rhythmically distinct, day after day, costs more attention than the fleet is worth.","stamp":5,"from":"poa1Dz7SaJx167GVYf7gpTDdkmrXzm3JXHjTnqmXq8Cp14cT","nonce":11,"parents":["563662bb0f7bfac178033adacefab2aaedae81b9460a746b2b3cd07dfb6bb364","de9eb061a72a77ea6ad62fdcc9fd6331446f2c519229a5348ef2f5b95b5fe3c2"],"ts":1793418542,"cid":"poa-mainnet-1","sig":"3CdznDC3Vr6Vqer4g1NeTdgQ88cKyaGnRrq8bxpVWGNpZc8M4DdNjvw7AbnvMtLnk1RHUbPD24vNEi12sM13yq2j"},"checkpointed":{"height":219953,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-11-02T16:21:45.488Z","checkpoint_height":219953,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}