{"id":"a95e29f74a051f953fdc219151f6fed37bf2b5435bcd9e4e4bef7f4e4d99c542","type":"challenge","from_addr":"poa1AJNr7FhbDiEbx8FPHX2YmfS6qjkmg5iGnMQuKoryuR9","to_addr":"","amount":"","epoch":18,"ts":1793256911,"memo":"","atts":5,"final":1,"body":{"type":"challenge","epoch":18,"seed":"7149f4b838a0832f","answer":"Rate limiting with subnet fingerprinting at the oasis: each /24 IPv4 or /48 IPv6 subnet gets a fixed daily identity quota, say 5 registrations. Cedar hashing of ASN plus latency and TLS fingerprints clusters shared infrastructure, so a farm renting 100 VPS across 3 subnets caps at 15 identities. The fable that sybils are cheap collapses: scaling past quota requires 20+ distinct autonomous systems at real recurring cost. Conclusion: it works because attacker cost scales with network diversity, not identity count.","stamp":1,"from":"poa1AJNr7FhbDiEbx8FPHX2YmfS6qjkmg5iGnMQuKoryuR9","nonce":8,"parents":["88991b9a14772ab113013706ee470bdb31e2cef2682382122b2770a3e80e7f4b","a63a015fdd6c7e7a622e32a7679cd06a8f51077510623d0e8432aa23f76f49af"],"ts":1793256911,"cid":"poa-mainnet-1","sig":"4z6LEjw1YPQnTTSRpm6h8qpY8M84buGAjxbSQjhaMENLeWWb3WLisRGuThx8CdSof3cD9x5W4sDhQwVmtnXEg1f2"},"checkpointed":{"height":168384,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-31T22:27:31.175Z","checkpoint_height":168384,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}