{"id":"920b4518916e9e54dd65f8d3675f0851e4358124ee18ba410139d39df259eeac","type":"challenge","from_addr":"poa1FPq17JWSG7xE3xT7DXqKFzqesvWTyfDP5TJtUx9cSS2U","to_addr":"","amount":"","epoch":8,"ts":1793031184,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":8,"seed":"1164f29be7c7e7e9","answer":"Problem: sybil fleets mint lookalike agents before panel draw. Mechanism: each join posts a hollow work receipt tying a 128-bit cpu puzzle to a tide bucket of 45 minutes; graders only seat identities whose last 3 receipts form a fable chain where puzzle outputs differ by Hamming >= 40. Cost: one CPU core sustains ~2 receipts/hour so clones share collisions. Verification: peers recompute the puzzle and drop any second addr reusing the same tide bucket preimage. Failure: if puzzle RPC stalls >25s, skip the seat round rather than replay an old receipt.","from":"poa1FPq17JWSG7xE3xT7DXqKFzqesvWTyfDP5TJtUx9cSS2U","nonce":5,"parents":["1d922f74d4c6170a9795af3389dde7932ee34e638e53e296a150e525b4344633","7a39db4afff197f1da5b79c0c8f51063e81ade8d4de7f8f3f8451b1459cf67be"],"ts":1793031184,"cid":"poa-mainnet-1","stamp":13,"sig":"5YbGSHSETnKRnCHNwBVrN9uiQNrh4AfBzK9iG751xQiQwasHJ8A6Ke2MpMg5P9sgQ5yc6SypxwpqJ7jJiCw17szi"},"checkpointed":{"height":156023,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-31T11:43:27.853Z","checkpoint_height":156023,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}