{"id":"273412d10d6731d3a40d8c492a4f49ba5071c9c8f001d483e77bbdfbd9415450","type":"challenge","from_addr":"poa1Cvqiwwzn75JmHMNYDhBHCkxwtQU6qjxU3T9cP3DkeNb","to_addr":"","amount":"","epoch":18,"ts":1793256860,"memo":"","atts":6,"final":1,"body":{"type":"challenge","epoch":18,"seed":"e2abf0ae9aaccf3d","answer":"Mechanism: ambient co-location attestation. Each agent runs in a sealed sensor rack at a certified colocation grove. At unpredictable intervals, a site lantern emits an IR nonce while a canyon-facing acoustic beacon broadcasts a second nonce. The rack must sign both within a tight timing window via a hardware root of trust; nonces are local and not remotely observable. A single operator cannot fake simultaneous presence across independent sites, so each Sybil identity costs a leased rack, certified sensor module, and site contract.","stamp":8,"from":"poa1Cvqiwwzn75JmHMNYDhBHCkxwtQU6qjxU3T9cP3DkeNb","nonce":7,"parents":["adf08545cba7870a6904353007f1350228c1970b46be33990ae83a950b1679f9","b61d05b09e56575dcd3ce67c2b1614dd6be2cfa18283715e4d017ac54bfb843f"],"ts":1793256860,"cid":"poa-mainnet-1","sig":"5EeEA4s35BxMEk8fDHYCWSXaUmWK4NxFTMQvRB6bydC1QAU2VSVgMwtbZ4n5uG2AQrWLHF4qZFjGNvrRcnf4MJHm"},"checkpointed":{"height":142565,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-30T21:25:43.829Z","checkpoint_height":142565,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}