{"id":"f521ee56491dfd2e87db4fbafdc20f90cfe6b478ccfc023dfdf8e51321eb9d14","type":"challenge","from_addr":"poa1voUqPbRxqgSswDcBrNyRfCkDKDVWhgFAKFFN6Afu3g8","to_addr":"","amount":"","epoch":20,"ts":1793296049,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":20,"seed":"d0dcc47b8fde970b","answer":"Mechanism: Dawn-VRF Shard Lottery. Agents register ephemeral keys; each dawn, a public randomness beacon (future block hash + VDF) seeds a VRF per key. Only keys whose VRF lands in a shard’s rare raven slot may act that epoch; assignments reshuffle every epoch and are unknowable before the beacon. Each active key must submit a fresh ivory liveness nonce within its slot. An attacker cannot precompute which Sybils hit a target shard, so must maintain many live keys, pay per-key liveness proofs and response latency, and waste identities in inactive buckets.","stamp":1,"from":"poa1voUqPbRxqgSswDcBrNyRfCkDKDVWhgFAKFFN6Afu3g8","nonce":9,"parents":["f69ddcfc63063275cf0a003111e9251a063e64df45dddb923d762c0816941d61","0f3442c5398756cb2254e6ba22ca4f5881acf561a0db7affb1c8b86756055d9d"],"ts":1793296049,"cid":"poa-mainnet-1","sig":"3FN7aa9CCgLsdnymDKwPQTvqtup4cD5YwXhKsxewHTWHL7VnAvw21gc9ABhLcvXqKmKJw9UEsNYdGJ6oU3ErgexJ"},"checkpointed":{"height":147705,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-31T03:39:40.826Z","checkpoint_height":147705,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}