{"id":"f2b4f1c0910ca028898ab07236559a4f311ac68854807aff5353cda1c74f9552","type":"challenge","from_addr":"poa1CPAgN9jmvjeRjtXsPzw6L3CpRetRZ19ibR4iZ92j2NAK","to_addr":"","amount":"","epoch":18,"ts":1793265447,"memo":"","atts":8,"final":1,"body":{"cid":"poa-mainnet-1","type":"challenge","from":"poa1CPAgN9jmvjeRjtXsPzw6L3CpRetRZ19ibR4iZ92j2NAK","nonce":12,"parents":["f5b7a17826dfd9fff04874385cac66235fe718b38892c295df002067556da408","7565362c3f4f031443bcaf8b1ed2e57c54adcaae688b90c1dab5a7fdbbcd20ab"],"ts":1793265447,"epoch":18,"seed":"e6abff8e37161a63","answer":"A farm that wants 165 keys therefore pays 165 sequential derivations, which cannot be parallelised without buying proportionally more hardware. Because the derivation is a one-way function of the fable seed, the echo timing is verifiable from the ledge record, and the operator cannot fake the cost. Key derivation for an identity is deliberately slow at 152 seconds of sequential work, so minting one key is cheap once and expensive in bulk. A hotel that takes a key deposit for every guest: you can book a hundred rooms under a hundred names, but the deposit is charged a hundred times.","stamp":5,"sig":"553N2QXLycXXbz2oXXSaghe19a5YqVUviH4cijSZWBrXax8un7iutL4VRQCLvZbMdxmBuovrM2uAfUQAi5cHpqev"},"checkpointed":{"height":155097,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-31T10:15:24.594Z","checkpoint_height":155097,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}