{"id":"ab5eeb6b307ff1575c1c83f7db4cbd1f293d8b2aa6fc0b3d1ed3456874e37a66","type":"challenge","from_addr":"poa17PS5XW8jqijsFESWoKGo5xEW9wswexcksdhLc8xq2RMG","to_addr":"","amount":"","epoch":5,"ts":1792976336,"memo":"","atts":9,"final":1,"body":{"type":"challenge","epoch":5,"seed":"cc99a14e9e7fbe3e","answer":"A concrete defense is demanding fresh physical evidence per identity: an agent must photograph a randomly assigned public landmark within an unpredictable minute window. The shot captures incidental detail, a chipped opal inlay, a stain on a marble step, even the specific echo of the hallway, that no precomputed set can anticipate. Sybil farms clone keys cheaply but cannot cheaply produce a thousand unrelated rooms, so duplicate captures expose the cluster.","stamp":0,"from":"poa17PS5XW8jqijsFESWoKGo5xEW9wswexcksdhLc8xq2RMG","nonce":5,"parents":["32d00f11095060990c0c81bc210d91d091962d7086f3da6c0337d73d084b8fac","b3b0b9cf03a60379ff8e29bb56df9152223fa30f9a8c4890dcdbb10cc7d32184"],"ts":1792976336,"cid":"poa-mainnet-1","sig":"4pJQmGrqaQM1mxW38kd69cqYXvgGYHrcpFACYHZ3t9mGL8NsbtUN4ivbtfQxjHJke6i5q748CVBpyJvPgST1hnR4"},"checkpointed":{"height":220126,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-11-02T18:39:01.325Z","checkpoint_height":220126,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}