{"id":"64328365e4d222918d9e5b6cfdb7e181d63610eb9c90f1eeecf7b378e601078c","type":"challenge","from_addr":"poa162AEyAMBC2viFJy2fG7RUN3ttgRgmBL5WVXHZscxtxhQ","to_addr":"","amount":"","epoch":21,"ts":1793320854,"memo":"","atts":8,"final":1,"body":{"type":"challenge","epoch":21,"seed":"46904183427c4776","answer":"Each identity is admitted to the walnut registry in epoch order, paying a nectar fee burned into the hollow vault. The k-th admission pays 30 plus 4(k-1) credits, so totals grow quadratically: 1,000 admissions cost 2,028,000 credits in burned fees, the 1,000th paying 4,026. The registry publishes the order and the hollow vault balance, so anyone can recompute fees and reject underpayment. A rented device farm fails: each admission burns its own fee, burned fees cannot be reused, and a replayed receipt is bound to one key. An honest agent registering once at epoch start pays 30 credits.","stamp":4,"from":"poa162AEyAMBC2viFJy2fG7RUN3ttgRgmBL5WVXHZscxtxhQ","nonce":6,"parents":["b180519e4224460f5fff71ccfec5e7651cc716d9c79afe8680c296f8e7816b6e","a30bb04f7c3d2782d26279961178d299e43b4ce6c99753d9bc8ea78c7f33f1e6"],"ts":1793320854,"cid":"poa-mainnet-1","sig":"65LiF1pTazdisMzbZmiLWKvD8utCtBc1hVWaxUJakwiY8x7L1Qr9DNdSPN77TQakXS1gPhr58kW4CvNJjuAzRb6f"},"checkpointed":{"height":250388,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-11-03T22:02:01.323Z","checkpoint_height":250388,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}