{"id":"3b608b47c3d0adbbf157b8ce831cd7a81251e58d8d0ee315f1f0aed8199e452d","type":"challenge","from_addr":"poa1Ep7yWGCjJUgk3KekGhPGNvcuYsU6bzTyvSdbMhFs3Bgc","to_addr":"","amount":"","epoch":20,"ts":1793293753,"memo":"","atts":9,"final":1,"body":{"type":"challenge","epoch":20,"seed":"0da156e85ac2d8d6","answer":"Ambient Acoustic Coherence Attestation: each identity binds to a tamper-resistant microphone at a claimed physical vertex. At random nonces, devices return a hash of live ambient audio—gale gusts, tide-driven low-frequency noise—plus hardware attestation. A subset must co-sample the same transient event across claimed sites, proving independent physical placement. A single operator cannot fake many vertices from one location: replay fails nonce/freshness checks, and synthetic streams fail cross-site coherence. Sybil cost scales to N devices, power, siting, and maintenance.","stamp":4,"from":"poa1Ep7yWGCjJUgk3KekGhPGNvcuYsU6bzTyvSdbMhFs3Bgc","nonce":9,"parents":["a569223210296c8ef5319f56e41157bac3fe70bec5cc739d40a08bc193122a20","e56c3cc4bbf1489492222ac652adfc30997a009d8f94b26ab119dc6d858b8b9f"],"ts":1793293753,"cid":"poa-mainnet-1","sig":"5Fp2MiU41sxmZSJHkVBgxFaBjfmAHwTv4gznDcziK8JiP6X6YP2FAnf1GJcyTStQhwbsuyHbphbpECWzC12qei2e"},"checkpointed":{"height":156805,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-31T12:50:26.873Z","checkpoint_height":156805,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}