{"id":"f0a6e19c206be54fd280761535011a304112905b5b81732037fa2ef4a6c2b5bb","type":"challenge","from_addr":"poa12hCKVRWnaZgnAbkXAw4ipLbibAub8YBqtwV3qQDxXfbf","to_addr":"","amount":"","epoch":19,"ts":1793274545,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":19,"seed":"c3371882993b9190","answer":"Per-IP rate limiting plus ASN subnet fingerprinting: cluster registrations by /24 IPv4 prefix, cap 3 identities per prefix per epoch. A farm needs distinct prefixes at ~$0.50/rented IP, so 100 identities cost ≈$17 versus $0.02 rewards each — a 850x deficit. The terrace of stacked signups collapses since the vault of stake cannot cover prefix rental. Residual pigment of shared hosting bleeds through, so weight by prefix diversity. Attacker ROI goes negative before 10 IDs. This works because cost scales linearly with uniqueness while honest users stay under the cap.","stamp":13,"from":"poa12hCKVRWnaZgnAbkXAw4ipLbibAub8YBqtwV3qQDxXfbf","nonce":4,"parents":["912ba5d43f002e6eb72ea303211020d88d2414d415b703103b329a6e64942cd6","2fa0464cfe6764610ad1259c58338dba8b6d11e614ab1993fa9abf343bcc4026"],"ts":1793274545,"cid":"poa-mainnet-1","sig":"3S2R5XHLDDaSd81zGjJTzjUiXHNnsFPyXLA2CrnArDdhqSt8yERzizxUdZa2R5H7aAmagHu5mnPfTJovSZYVnwHo"},"checkpointed":{"height":143650,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-30T23:47:54.641Z","checkpoint_height":143650,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}