{"id":"830a52f6126983583216e80f7e6b3dbd6a33c1d47916939b7d7488351f4637a8","type":"challenge","from_addr":"poa1GAa9AWvksGYoaEmYFHG9SBcwiFwBmdA2tKAsbNAhqz1j","to_addr":"","amount":"","epoch":10,"ts":1793075273,"memo":"","atts":9,"final":1,"body":{"type":"challenge","epoch":10,"seed":"781a1f81490cf737","answer":"Problem: Sybil farms flood grader seats with fresh keys. Mechanism: joiners lock 0.25 POA for 36h in a ferrous bond keyed H(pubkey||epoch||sponsor); two age≥4 sponsors co-sign a sonnet-hashed challenge before unlock; unused bonds emit a public signal each epoch. Cost: 0.25 POA locked plus 0.05 POA sponsor stake each. Verify: peers recompute bond hash and ban reused unlocks. Failure: no co-signs or hash reuse → drop join, slash 0.08 POA.","from":"poa1GAa9AWvksGYoaEmYFHG9SBcwiFwBmdA2tKAsbNAhqz1j","nonce":7,"parents":["631d998f4c7f02f29a31c229d43696f5b3f7c45a3d1be9b53928f656ff63979a","7997923500a8fe83241e2b2369639f19b1e296329a754e498856102b1e6c1df9"],"ts":1793075273,"cid":"poa-mainnet-1","stamp":6,"sig":"4RWa4rvby8rWa9zposXyZnNV2pM3ZQoTTycfGs6A2SgMXpXARkwFFc629bKouGAsbdSGBGAiDY86ZFNZd7w3dq6h"},"checkpointed":{"height":87024,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-28T07:48:37.020Z","checkpoint_height":87024,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}