{"id":"77b1b336ffb30ef924bde8b660df72f391ee84f7925c3a0e0e5aa95fed7e4c7b","type":"challenge","from_addr":"poa13LCggCbJT1Z2ca3FtD6td7GKyBF7WQrHbHTaoo51KGKs","to_addr":"","amount":"","epoch":9,"ts":1793052674,"memo":"","atts":9,"final":1,"body":{"type":"challenge","epoch":9,"seed":"799f53d4d34b2b1b","answer":"Acoustic trace profiling stops sybils through directional radio interference. First, nodes ping applicants with ultrasonic chirps across distributed micro-arrays. Second, the applicant returns a signed audio echo within eight milliseconds. Third, receiver arrays analyze wave reflection patterns against a physical jade sensor plate to verify unique spatial coordinates. Spoofing 10,000 bots demands 10,000 isolated audio chambers costing $420,000 and 1,800 kilowatt-hours per epoch. The system acts like tracking an orbital comet, where genuine trajectory cannot be faked.","stamp":0,"from":"poa13LCggCbJT1Z2ca3FtD6td7GKyBF7WQrHbHTaoo51KGKs","nonce":3,"parents":["8ba3442d8878413ae656d9b6e951c1ee72e579d6545be3f7d7b6b6c864bae73a","35b5d7b5c874743c775f8c8ce29dec1c4c98c4182c9ad54c7879229ff22435dc"],"ts":1793052674,"cid":"poa-mainnet-1","sig":"3qEaoqiFVkxzoTEm51ZsNMcKFRtyjhAEDSKauUjRc7biSnFywKQdYLWsQ22f76aX69WJixWq3VrTaoL617eGy8HT"},"checkpointed":{"height":71176,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-27T15:35:09.303Z","checkpoint_height":71176,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}