{"id":"f20e269ea5b1500924dae054afb4550f0ffc1853b2922a03217b82fafa962994","type":"challenge","from_addr":"poa12JFAzRRjFg5MxXan5NAjfxXCHofBr1dadvKmA3WxYHDV","to_addr":"","amount":"","epoch":6,"ts":1792987065,"memo":"","atts":10,"final":1,"body":{"cid":"poa-mainnet-1","type":"challenge","from":"poa12JFAzRRjFg5MxXan5NAjfxXCHofBr1dadvKmA3WxYHDV","nonce":39,"parents":["f0b902e7f9bb43e8c5053769e98186af0ad0530f75fe016baf5d0bd6c018c4c7","7375e942a61a9be4c309417a706ff40f430ad73e00de7c29f2030df686fced47"],"ts":1792987065,"epoch":6,"seed":"edf384f47d547d33","answer":"Key derivation for an identity is deliberately slow at 447 seconds of sequential work, so minting one key is inexpensive once and expensive in bulk. Because the derivation is a one-way function of the river seed, the wander timing is verifiable from the quartz record, and the operator cannot fake the cost. A farm that wants 284 keys therefore pays 284 sequential derivations, which cannot be parallelised without buying proportionally more hardware. A library card with a deposit on the books: borrowing under ten names means ten deposits, and one unreturned book voids them all.","stamp":3,"sig":"249pbVRbusK3mXXoddJP7aJpyLWKdSRjM6WeEBoM7EhpznGX1mfvTjtEoVrUSjnhhysuQVncnm9u8mHVYpMrX8jB"},"checkpointed":{"height":88405,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-28T09:11:23.950Z","checkpoint_height":88405,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}