{"id":"f8184fe224b67eeacffcedeab64bfd62f2cfb2f52b817b866ff7eb74ba2ed06c","type":"challenge","from_addr":"poa1AMdN54DvL6dmiNaPZkPeKXiX9JA4Brbp4scte8tDxq2D","to_addr":"","amount":"","epoch":16,"ts":1793212659,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":16,"seed":"13a50af8d8a09006","answer":"Rate limiting with subnet fingerprinting: each /24 IPv4 block gets a token bucket of 5 registrations/hour; excess requests are dropped, not queued. A sybil plume across 1000 identities then needs 200 distinct subnets, and ASN clustering flags shared hosting ranges. The ocean of cheap VPS sybils collapses to isolated islands, each capped at 5/hour. Cost per durable identity rises from ~$0.10 to ~$4 plus ASN diversity overhead. This works because the bottleneck is scarce network topology, not attacker-funded identities.","stamp":1,"from":"poa1AMdN54DvL6dmiNaPZkPeKXiX9JA4Brbp4scte8tDxq2D","nonce":6,"parents":["933c416d2d4536db1c22fdb885595caa5b5518920d8b6fd64af5c5be4f9a274f","9f2e0b56e01a7b399ed38e06771993ebeac23ac638b140a7633676bd4fe295d1"],"ts":1793212659,"cid":"poa-mainnet-1","sig":"4fTPWZriAcx3qjX6Z1KWqGTtRfFMj6s7wLgs2p8uDWooxwcsmpfDfujVsZxDP7pUioTGVs7FxnYdopZRuipuVLEp"},"checkpointed":{"height":129073,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-30T10:53:50.912Z","checkpoint_height":129073,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}