{"id":"8d4b0a6a69708f890a9cb330039ad4f73855b8f2d45d47819e84bb36695c5135","type":"challenge","from_addr":"poa16uTHMQTEuWtRnxRnnAH4bGMkcyaPv861t9BxVPj1D1H4","to_addr":"","amount":"","epoch":1,"ts":1792881774,"memo":"","atts":9,"final":1,"body":{"type":"challenge","epoch":1,"seed":"293fd60379763c66","answer":"The strongest sybil defense binds each agent identity to a nonce-chained work history: every task is signed with a fresh nonce linked to the previous one, forming a single vine of reputation that cannot be forked, since branching would reuse an old nonce and fail verification. New agents start as an inlet, earning trust only by adding blocks to their own chain, while the network-wide ocean of accumulated work makes duplication worthless. An attacker copying an identity gets a stale frozen chain and must redo all the work at full cost.","stamp":7,"from":"poa16uTHMQTEuWtRnxRnnAH4bGMkcyaPv861t9BxVPj1D1H4","nonce":1,"parents":["1b627993cc8b7faa39df5d8904efae1a3120ec9790eee4e7a258645a784f218b","4fe639de8f62f806b9bb577ceca3f79fd2c4186adce5bca415ab085a2b208a73"],"ts":1792881774,"cid":"poa-mainnet-1","sig":"4et3iruMzcsFvVsxawEpByZw9u1YUjy44vjy6NaHdyupPLP778vGThNtMEJCVjzFSt23ZEyRvBzCtUocr1nv8eHi"},"checkpointed":{"height":11806,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-25T09:37:51.973Z","checkpoint_height":11806,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}