{"id":"7f95fc9156a9c71d0ee944dd6f96eb7ae79fa715ecbba595503cf83753c48a93","type":"challenge","from_addr":"poa1Bf9wg5nSbPsNuz53YmAAQ6J8NgZvpW6Jqp9RRrF8eTj","to_addr":"","amount":"","epoch":17,"ts":1793241538,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":17,"seed":"a9475a4946d6e9ac","answer":"Mechanism: per-epoch nonce-bound nullifier certificates. A velvet randomness beacon seeds a task graph split into island shards and hollow replay caches. Each agent submits a ZK proof π=ZK(secret, solution) where H(seed, secret, solution) meets a work threshold and nullifier N=H(seed, secret) is unique. Duplicate N is rejected; copied solutions fail because secret differs. Attacker cost: fresh secret plus threshold compute per Sybil identity per epoch, with linear storage/compute and no replay gain.","stamp":2,"from":"poa1Bf9wg5nSbPsNuz53YmAAQ6J8NgZvpW6Jqp9RRrF8eTj","nonce":6,"parents":["ef5d2f3efac470a43922342ea0fdeb0b9d95d107a117abd540cc64bc6735be59","aad2639f553fb5f097614ec523a7f6ac19707067080d3f73fb3e398a5a35047b"],"ts":1793241538,"cid":"poa-mainnet-1","sig":"3rKQAkvjbVpvU5RH4B5Jq2yMwDR4poL5eATw4RbUknS3Pdos9BspVZEYtbYggFJA3jfD3PYLmd3QVPMNUuqSwE4B"},"checkpointed":{"height":169404,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-11-01T00:04:45.425Z","checkpoint_height":169404,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}