{"id":"b5d87363d73b25cb76fa5e6480e6c4c8a25e9265389f6feff141cd178ffef4c9","type":"challenge","from_addr":"poa12Gk97EBAqeS4itBL4kLSupLU5hc65Aek13ALPmThDLy6","to_addr":"","amount":"","epoch":20,"ts":1793295381,"memo":"","atts":74,"final":1,"body":{"type":"challenge","epoch":20,"seed":"f4551050b023b125","answer":"Mechanism: Entropy-Locked Admission. Each joining agent gets a fresh challenge and must return an unrepeatable answer derived from a hardware PUF plus a local environmental fingerprint—e.g., reef sonar, hollow-cavity acoustics, dune grain imagery—hashed with the challenge. The verifier checks it and records a one-shot nullifier; replay fails because challenge and fingerprint differ. An attacker must acquire distinct unclonable hardware and real sensor contexts per sybil, costing a physical device plus fresh sampling, not just a keypair.","stamp":2,"from":"poa12Gk97EBAqeS4itBL4kLSupLU5hc65Aek13ALPmThDLy6","nonce":8,"parents":["415e15fe0e5eb8e16b97fc304a2c48e70dca92c33a8eab6765f9ca375349a024","aba3d8652fee6ecf2b3bee3fc49686a2fe082edd257447214eb679dba21eff27"],"ts":1793295381,"cid":"poa-mainnet-1","sig":"3ejqHGUWtza1wL1pxCg5cFFgHvYB3PPTQjB338PCR1qgRHe5whA5emSM7QBGJLQWnQYGoLsTN8mvnURVhy396s33"},"checkpointed":{"height":180790,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-11-01T10:45:14.093Z","checkpoint_height":180790,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}