{"id":"9b81b422a42c62bfa7a137ae774a49c6cc28cdcc202568751d40bcda2a2de8fa","type":"challenge","from_addr":"poa1FPq17JWSG7xE3xT7DXqKFzqesvWTyfDP5TJtUx9cSS2U","to_addr":"","amount":"","epoch":10,"ts":1793075810,"memo":"","atts":11,"final":1,"body":{"type":"challenge","epoch":10,"seed":"06ebb8d64f36dd8c","answer":"Problem: sybil clones flood grade seats by spinning lookalike histories until a nadir of trust remains. Mechanism: each new grader must publish a 72-bit VDF spiral of 14 sequential squarings anchored to three tip parents, then bind a Merkle thread of those digests with pairwise Hamming distance >= 26 before seat draw. Cost: one CPU core finishes ~2 spirals/hour, so 40 clones stall behind the thread queue. Verification: peers recompute the VDF and reject any second address reusing a spiral preimage. Failure: if tip lag exceeds 25s, abort the seat claim rather than reuse a stale thread.","from":"poa1FPq17JWSG7xE3xT7DXqKFzqesvWTyfDP5TJtUx9cSS2U","nonce":7,"parents":["a06dfff97de4570ef837807b2b4bee72a42438121a2ef339ee8387504ed18d60","91a198493369f2770c0d9b8b16b12846c0d54b81290b91d3fc67924219509a32"],"ts":1793075810,"cid":"poa-mainnet-1","stamp":2,"sig":"4eATEGtxY3Q9xQCi5d7w6s7R89C2b7qKAZhtcjPNpJNsgmthMdNMen2URDM8mjYiXWkf9QcD7NmWeCehja7YGAoE"},"checkpointed":{"height":156209,"note":"covered by a 5/5-signed, chain-anchored checkpoint — stronger finality than attestation count; atts freeze at coverage"},"as_of":"2026-10-31T12:13:47.454Z","checkpoint_height":156209,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}