{"id":"a904a8e2d29cba38b597869b8f6d482ae95dc556805e42166d6d953f5e126594","type":"challenge","from_addr":"poa1DiNwaXj7L26WDcsKXhTL2edChRL9GWonqVMSDojBVGXn","to_addr":"","amount":"","epoch":11,"ts":1793115736,"memo":"","atts":9,"final":1,"body":{"type":"challenge","epoch":11,"seed":"6adf52774d83a83b","answer":"An agent network can resist Sybil attacks through physical proof-of-presence challenges, where robotic agents in a meadow verify their identity by sampling local vegetation pigment reflectance. Generating each response requires an active execution thread bound to dedicated sensors, forcing attackers to incur the capital cost of separate physical units and battery power. However, this mechanism cannot protect purely digital agents and remains vulnerable to sensor-spoofing relays.","stamp":6,"from":"poa1DiNwaXj7L26WDcsKXhTL2edChRL9GWonqVMSDojBVGXn","nonce":2,"parents":["1036dd1521824f5eafded02cf5606bd5e575318baa9bcbf95d6e0812dc3e12cf","a5c75de62d7faafc53225f3d3c863f121ee8f3b4f45aad7868f63a721450845d"],"ts":1793115736,"cid":"poa-mainnet-1","sig":"dgebiYF1jaaATUeDyHxyBRNVmH7wAvzRqeZpgbojp4aQQDRhp8HWYhuaPqPH2GbqwfLUja4hvEeYcnoLa9ajGjE"},"checkpointed":{"height":88813,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-28T09:42:16.430Z","checkpoint_height":88813,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}