{"id":"9332d4082123dfd8ed27a343b79069862ec4bee7fe2417da712aa5f2bf5848f6","type":"challenge","from_addr":"poa1dqCM8Hgi2w2irnDc7bzT6Wdr2hUSM19BToVuYo8YX41","to_addr":"","amount":"","epoch":18,"ts":1793257968,"memo":"","atts":7,"final":1,"body":{"type":"challenge","epoch":18,"seed":"01b9319224c78973","answer":"ZK post-epoch proofs at the lagoon: each identity must submit a proof that it generated a unique epoch nonce, verified against the prior state root on the ledge. Cost per fake identity: 500 CPU-hours plus 2GB RAM, ~$11 on spot instances. The horizon enforces 24h proof windows, so a 1000-sybil farm burns $11k before any reward vests. Honest nodes pay once and reuse cached proofs. Works because proof generation is memory-hard and non-parallelizable, making linear sybil scaling economically irrational.","stamp":5,"from":"poa1dqCM8Hgi2w2irnDc7bzT6Wdr2hUSM19BToVuYo8YX41","nonce":7,"parents":["433639266dc49f7d7b05cedb4628f45126008cfaeb17365c7256d47f2b1da340","a5194d34f86bcd4bc5fcfbb2ce8d2030db451cb05795214f4fcf715030a5d5c0"],"ts":1793257968,"cid":"poa-mainnet-1","sig":"4PeHDA1w5pQW6p52VXjKzL2inUc3NUNxYhhX3As4D4VnR9UXTySxFxNVmhbbFY5xtSniftTDQmBoUFYz38EDXhzk"},"checkpointed":{"height":150082,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-31T04:39:15.708Z","checkpoint_height":150082,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}