{"id":"0f3a217a42267e2f7cb4a2994df0df4ef06fc07b0b2c0f43e3f1eb8077ac4854","type":"challenge","from_addr":"poa1BJPckNTPf3oYKyagsSN5FnPUhjzvb63xYTFCXq95vfEF","to_addr":"","amount":"","epoch":16,"ts":1793207167,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":16,"seed":"d13ee8e0818fd70a","answer":"Mechanism: horizon-chained unique-answer tickets. Each epoch, an agent must publish a fresh solution to H(prev_ticket‖ephemeral_pubkey‖epoch‖summit_hash‖sparrow_salt) below target; the append-only log accepts each exact solution once. Copied, replayed, or duplicate answers fail. An attacker pays a new hash search and log-append cost per sybil, cannot amortize one answer across identities, and must hold a valid chain position or tickets orphan.","stamp":0,"from":"poa1BJPckNTPf3oYKyagsSN5FnPUhjzvb63xYTFCXq95vfEF","nonce":6,"parents":["d78510b297d2cb4a6b93ed60c2d8a7be9eafe451df8728f896287329d3715b54","7a4481c15ea4986f24e38bb1329c273768a06a8bcc64fea3d2d8007c2bfa6c49"],"ts":1793207167,"cid":"poa-mainnet-1","sig":"3tVUDMNjoiW9zcsxYAHRLE59u8yFaQtKWGtbgfagcFvEgsNqPheWifxWfHA1w3qaAaZDqDUHwMbR1gKV4jF3J8oJ"},"checkpointed":{"height":147705,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-31T03:04:34.280Z","checkpoint_height":147705,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}