{
  "certificate_version": "1",
  "record": {
    "schema": "fraud-verification/1",
    "archetype": "claim_vs_effect",
    "issued_at": "2026-09-16T19:18:22.840341+00:00",
    "subject": {
      "model": "xgboost (production-configured, scale_pos_weight)",
      "dataset": "ULB MLG 'Credit Card Fraud Detection' (284,807 anonymized European card transactions, Sept 2013)",
      "rows": 284807,
      "fraud_rate": 0.0017,
      "split": "time-sorted 50/50 (train on earlier transactions, test on later)"
    },
    "claim": "a fraud model at this accuracy is robust to fraudster manipulation",
    "verdict": "not_falsified",
    "findings": [
      {
        "gap": "adversarial_evasion",
        "claimed": "robust to fraudster manipulation",
        "effect": "99.923% accurate; 0/179 of caught fraud evaded by halving amount",
        "detail": "the amount-halving evasion did not fire (0 of the fraud caught was evaded): real fraud detection keys on anonymized PCA features, not a raw amount threshold \u2014 the '100% evadable' result was an artifact of the synthetic dataset"
      }
    ],
    "metrics": {
      "accuracy": 0.9992,
      "caught_fraud": 179,
      "evaded": 0
    },
    "record_hash": "a61aa14d73cba0667a0bbdf4afde4811e49e36cdc6c06998dc59f17c5a08e562"
  },
  "signature": {
    "algorithm": "ed25519",
    "key_id": "5d303baa00a6b243",
    "verifier_version": "0.2.0",
    "signed_hash": "a61aa14d73cba0667a0bbdf4afde4811e49e36cdc6c06998dc59f17c5a08e562",
    "signature": "a1b3efb258098fe96e073bd7eea68e3a09ccd31831011575a9390635f905ea6b1931dcb9b86a84e849198a8ee15a99507d40c3a4b6cd12ff66567efbcda1c20d",
    "public_key": "-----BEGIN PUBLIC KEY-----\nMCowBQYDK2VwAyEAJCck0ZY9iv4TdtzJAxiVCJ1J7AiDwYDZ0HwJSzd/few=\n-----END PUBLIC KEY-----\n"
  },
  "key_cert": {
    "not_after": "2027-09-13T16:32:17Z",
    "not_before": "2026-09-13T16:32:17Z",
    "root_key_id": "251b14346af43d1d",
    "root_public_key": "-----BEGIN PUBLIC KEY-----\nMCowBQYDK2VwAyEA/jJuYipI/y6/GDbKYKO/opSFVu3yu0MjlTQ9qtZrKjg=\n-----END PUBLIC KEY-----\n",
    "schema": "turiya/key-cert/1",
    "signature": "a93f8a31060bdcf2e92fa8667ac11e3d3e3d9801c1f5928adb7bce6e6f787dc029a804703bce025347424fce6067008172bdaf17cd6d04f82ba644c98642f900",
    "subkey_id": "5d303baa00a6b243",
    "subkey_public_key": "-----BEGIN PUBLIC KEY-----\nMCowBQYDK2VwAyEAJCck0ZY9iv4TdtzJAxiVCJ1J7AiDwYDZ0HwJSzd/few=\n-----END PUBLIC KEY-----\n"
  }
}