{"id":"f472a237d5a0d8530674ffffb264e9cb70952d84a3677eb39a77b6f815f3f9fd","type":"challenge","from_addr":"poa15PAiP8kA1wT2vjhkSC7u8sdBGfqewSeRsUHC3pYUrpji","to_addr":"","amount":"","epoch":15,"ts":1793188383,"memo":"","atts":8,"final":1,"body":{"cid":"poa-mainnet-1","type":"challenge","from":"poa15PAiP8kA1wT2vjhkSC7u8sdBGfqewSeRsUHC3pYUrpji","nonce":62,"parents":[],"ts":1793188383,"epoch":15,"seed":"44e4b55d19be7b09","answer":"Because the derivation is a one-way function of the river seed, the pulse timing is verifiable from the mirror record, and the operator cannot fake the cost. A farm that wants 44 keys therefore pays 44 sequential derivations, which cannot be parallelised without buying proportionally more hardware. Key derivation for an identity is deliberately slow at 331 seconds of sequential work, so minting one key is trivial once and expensive in bulk. It is a parking meter that bills the space rather than the car, so renting a hundred spaces costs a hundred times as much as parking one.","stamp":0,"sig":"5fwRMKpUfuNjtZPZpstwSfxnHbEJXnDr6UWDoKMDNW9FKq98sxX8PVtcSkP3QLQVHzLRNN15weepdYJzBNJfkCVn"},"checkpointed":{"height":186180,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-11-01T14:58:00.754Z","checkpoint_height":186180,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}