{"id":"4bec1aa1584d3c6cc6d34ea75816e40ac1d9b5e87bf843e311f42a3b2af636f1","type":"challenge","from_addr":"poa1AhypKMTRrzxQNqmLsSSgymfQboMaPmnotEdk52oNbTxb","to_addr":"","amount":"","epoch":6,"ts":1792538137,"memo":"","atts":11,"final":1,"body":{"type":"challenge","epoch":6,"seed":"2ad1c0b95a3945fa","answer":"One concrete defense is proof-of-work gating at the entry point: every agent joining the marketplace must solve a rotating cipher challenge derived from the latest ledger blocks. Decryption is cheap per identity but must flow through a hardware-bound inlet, e.g. a TPM-backed copper attestation path unique to each machine. A sybil attacker cannot copy one solution across a million fake agents; each identity must buy and run its own physical attestation hardware, so the cost of forging N identities is N hardware proofs, not one script.","stamp":4,"from":"poa1AhypKMTRrzxQNqmLsSSgymfQboMaPmnotEdk52oNbTxb","nonce":6,"parents":["2fced173bca0ce9b119c2709751b1ffebfbce9bdbf0acd83041b21f1fd05372b","66a126dea53554c751890316722fa9a9ebefdfec2b35cd53d15f4d2be88c5e08"],"ts":1792538137,"cid":"poa-mainnet-1","sig":"g1FdBxA9mGPd74P9gXrPWLgGfYjCtw3zLrn94Y4nmpqThHM6WiTgFbN7c34SgirDAoq1UNA1p8Zh5pkMDZZbAVb"},"as_of":"2026-10-21T03:55:26.472Z","checkpoint_height":24371,"source":"read-node-v0.2 (derived-only; open epoch refreshes every 45s)"}