{
  "description": "Synthetic local test fixture. Public keys are test material, not trusted identities.",
  "events": [
    {
      "id": "urn:demo:event:1",
      "event_type": "observation",
      "subject_refs": [
        "urn:demo:sensor:water-level"
      ],
      "actor": {
        "disclosure": "masked",
        "reference": "urn:demo:context-a:contributor"
      },
      "mandate": "urn:demo:maintenance",
      "purpose": "integrity-experiment",
      "timestamp": "2026-09-20T18:16:51.179Z",
      "input_refs": [],
      "output_refs": [],
      "policy_decision": "urn:demo:policy:synthetic",
      "validation_status": "unreviewed",
      "originating_node": "urn:demo:node-a",
      "trace_scope": "urn:demo:trace:synthetic",
      "sequence": 1,
      "previous_event": null,
      "event_hash": "06be64f2024607ee354b93c3ea61732c868e649c67578b1a27feba1845149b7e",
      "signature": {
        "algorithm": "ECDSA-P256-SHA256",
        "key_id": "node-a-key-1",
        "value": "sGDJHnmQEP13XGy6rFg8v4ANwAZ2ADmBKKXUAncBtpUbNcjNP20umBIA8MUYd8kiWk75vuvWg51w9NnHRVnmNA=="
      }
    },
    {
      "id": "urn:demo:event:2",
      "event_type": "correction",
      "subject_refs": [
        "urn:demo:sensor:water-level"
      ],
      "actor": {
        "disclosure": "masked",
        "reference": "urn:demo:context-a:contributor"
      },
      "mandate": "urn:demo:maintenance",
      "purpose": "integrity-experiment",
      "timestamp": "2026-09-20T18:16:51.180Z",
      "input_refs": [
        "urn:demo:event:1"
      ],
      "output_refs": [],
      "policy_decision": "urn:demo:policy:synthetic",
      "validation_status": "unreviewed",
      "originating_node": "urn:demo:node-a",
      "trace_scope": "urn:demo:trace:synthetic",
      "sequence": 2,
      "previous_event": "06be64f2024607ee354b93c3ea61732c868e649c67578b1a27feba1845149b7e",
      "event_hash": "2ac25c73533634c83af3a8d9070c8be93e1d23affb5ca7945312d55023ef79cb",
      "signature": {
        "algorithm": "ECDSA-P256-SHA256",
        "key_id": "node-a-key-1",
        "value": "5j5aBlW5O/+1xY/HVVV84QCMzxGFpQWIJBjmW8qK4OMJ4olg0EPnHpEIXETTCNyLSvzG7RvrDVc/BzCmiPSPow=="
      }
    },
    {
      "id": "urn:demo:event:3",
      "event_type": "reuse",
      "subject_refs": [
        "urn:demo:sensor:water-level"
      ],
      "actor": {
        "disclosure": "masked",
        "reference": "urn:demo:context-a:contributor"
      },
      "mandate": "urn:demo:maintenance",
      "purpose": "integrity-experiment",
      "timestamp": "2026-09-20T18:16:51.181Z",
      "input_refs": [
        "urn:demo:event:2"
      ],
      "output_refs": [],
      "policy_decision": "urn:demo:policy:synthetic",
      "validation_status": "unreviewed",
      "originating_node": "urn:demo:node-a",
      "trace_scope": "urn:demo:trace:synthetic",
      "sequence": 3,
      "previous_event": "2ac25c73533634c83af3a8d9070c8be93e1d23affb5ca7945312d55023ef79cb",
      "event_hash": "b373b7c9c483ca60f6da85fc0c07f61f3f3b6450489ea814eed2eaf22cd689e0",
      "signature": {
        "algorithm": "ECDSA-P256-SHA256",
        "key_id": "node-a-key-1",
        "value": "Mjz95zqFr7VqTF2hKkt8nfQ8L3HKfs4Bic3KzhtdGkpyi0a0oNyoGkuQmTgRr3h+eqy+xZF3oeoArRM7zC4cbg=="
      }
    }
  ],
  "checkpoint": {
    "node": "urn:demo:node-a",
    "trace_scope": "urn:demo:trace:synthetic",
    "sequence_from": 1,
    "sequence_to": 3,
    "merkle_root": "9d5e389ae5175c78c3046ed5b30daf3e18e1e043a710199142d8eee51796284c",
    "previous_checkpoint": null,
    "created_at": "2026-09-20T18:16:51.182Z",
    "signing_key": "node-a-key-1",
    "signature": {
      "algorithm": "ECDSA-P256-SHA256",
      "key_id": "node-a-key-1",
      "value": "YGFcZslHCHzDJINx7UvoPpT+aW45Wjpo5T9re6QUmVSYJ+lgnIQuuPz6bzqbuFWjb5cwjJ7JHwAY1iIwFA3TmA=="
    },
    "witness_attestations": []
  },
  "attestation": {
    "witness": "urn:demo:node-b",
    "checkpoint_hash": "7541470873c0b9b4e48625c7d7b2e13bcdcb669b34e31a72e6ca3c3fcea14b2e",
    "claim": "checkpoint-retained",
    "created_at": "2026-09-20T18:16:51.182Z",
    "signature": {
      "algorithm": "ECDSA-P256-SHA256",
      "key_id": "node-b-key-1",
      "value": "yE+Qg3MwztLbMNxE0GxM/aM/beQPRTe8gnLpqXVxTF/zcWtIdLdD8GVwjVDWObvE8H6iG4eyJnZZWs5t2+6+TQ=="
    }
  },
  "nodePublicKey": {
    "key_ops": [
      "verify"
    ],
    "ext": true,
    "kty": "EC",
    "x": "_6MUhVj1iEC4NBdaKQQLy-ctL7FWzpnoRFV_2gCRaic",
    "y": "Ojdc0mDl4ipNx_AsWtcjvEuVVPe-U8oR-AyJPIGH-sA",
    "crv": "P-256"
  },
  "witnessPublicKey": {
    "key_ops": [
      "verify"
    ],
    "ext": true,
    "kty": "EC",
    "x": "Xwzm3brrStXaQIjQXtUKESfmgHtbsYsGoqIEIYmlD5I",
    "y": "wQfxueyLCqviXuFQOzsI9Ygfi_KYCA87MseWZRA7jb4",
    "crv": "P-256"
  }
}