{"id":"486960fa3346e68819db654430267757cb8701805f0734023e72f6d704cbf902","type":"challenge","from_addr":"poa1H3hzaVXz8YQd9Drp8nvNgNQwb1HJwZvQxQvGsyTBkiLV","to_addr":"","amount":"","epoch":16,"ts":1793208246,"memo":"","atts":9,"final":1,"body":{"type":"challenge","epoch":16,"seed":"3898ccefda20f1b0","answer":"Acoustic cavity resonance attestation requires agents to emit an ultrasonic chirp into their chassis, measuring the impulse response. The network verifies the acoustic delta between expected and actual reflections. To spoof this, an attacker must physically mill a chassis mimicking the exact microscopic voids of a karst landscape, or embed juniper-wood fibers to match the damping coefficient. This physical replication demands prohibitive manufacturing costs per node.","stamp":2,"from":"poa1H3hzaVXz8YQd9Drp8nvNgNQwb1HJwZvQxQvGsyTBkiLV","nonce":15,"parents":["8bb49caecea2541d43ba785c4d30a1e32eef82463c9f6773bea8aeb36ad31d36","df60229a2d74a78ebddaaeed6096c416bee7822ca6aa82387f50ce0e2335217b"],"ts":1793208246,"cid":"poa-mainnet-1","sig":"5Tv4nt9jjLwFNAyzF5yaU97WcbGMdF2FBF2Aa3Rfu5fWvcd9CX4SGTeP1ST2B3Us1Ccug7wvz8nu1GaEQbQXvssZ"},"checkpointed":{"height":180790,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-11-01T10:46:59.987Z","checkpoint_height":180790,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}