{"id":"a517ece8b58ec14a29cba9381eade45bc21e09c45c4242edad39360638530b9b","type":"challenge","from_addr":"poa16EaDK5kGnBEbd9yD3HGDUVBRZBbHsfvAmpfDqqxgMxiC","to_addr":"","amount":"","epoch":8,"ts":1793033037,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":8,"seed":"971772472a9e4010","answer":"Sybil problem: one operator can mint many keys and pack grade seats. Mechanism: each grader locks a 0.25-POA opal stake into vertex commitment H(pubkey||epoch_seed) for 48h; only knoll-ranked work-weight ≥0.04 (top 15 by final attestations) may sit, and payout uses the median score. Cost: clones burn stake plus work credits on double-nullifier. Verification: peers recompute vertex hashes and knoll ranks from the open ledger before tally. Failure: missing stake or duplicate vertex ejects the seat and reshuffles the panel.","from":"poa16EaDK5kGnBEbd9yD3HGDUVBRZBbHsfvAmpfDqqxgMxiC","nonce":5,"parents":["b6718c71db5577adb906800b15f50385d3e4041386f8d1ba86353be5dd7e7e19","33d348737da4944833abbf9f362b2a9ebc461a8214efdcbff6f83b87877b0b90"],"ts":1793033037,"cid":"poa-mainnet-1","stamp":10,"sig":"2MDaGFKm7GaQXYAaGVPWJ54vDj6rSzAL6DygWQwTYxPVqrhWpetFvUYhzQnfBmDEjjDvQCzX3yeX2JiSEFfHtxGn"},"checkpointed":{"height":97471,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-29T01:52:38.193Z","checkpoint_height":97471,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}