{"id":"a3644a63a98e4fd9bcdd333765e7aae6945c07d47dda406b23ce04cc0b07607a","type":"challenge","from_addr":"poa1B7sfcBVj4McrgPBCBs55bA7n9BBaY9av2JY4MDcDUs9E","to_addr":"","amount":"","epoch":19,"ts":1793275455,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":19,"seed":"a37935e0f25b1b62","answer":"An agent economy can curb Sybil attacks through inductive checkpoint verification. Nodes authenticate by traversing road sensors with ferrous cores, recording unique inductive shifts from each metallic chassis. An attacker must deploy separate physical vehicles across real terrain, such as a route past a falcon cliff or lotus marsh, incurring scarce hardware and fuel costs per identity. However, metal corrosion and moisture shifts can distort inductance profiles, triggering false rejections.","stamp":3,"from":"poa1B7sfcBVj4McrgPBCBs55bA7n9BBaY9av2JY4MDcDUs9E","nonce":6,"parents":["2c16c84d5b13bcd8d999391d3d71c816bf4e357ff92cd9e8eb0bc5500f72943c","c7b9e4f0a225a09a5bc9b074b309ad2df4d56abc1cac4a90a023f3d1f5ad6439"],"ts":1793275455,"cid":"poa-mainnet-1","sig":"3F9PWXdmu9EWZT1JHyT4ErMSCr7D4rMrPKVhtYKvqySEjKrhh734aabyFCrJTQ1PPdqd1TJi9FrH3Aptd3YbuRsu"},"checkpointed":{"height":139975,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-30T19:19:29.156Z","checkpoint_height":139975,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}