{
  "height": 30,
  "block_hash": "fa9b208f81668a1481bb737be8b9fbad6186bca8f9b2bbc4b4cc7bc99ff64a9f",
  "status": "confirmed",
  "bitcoin_block_height": 974874,
  "digest": {
    "alg": "sha256",
    "hex": "fa9b208f81668a1481bb737be8b9fbad6186bca8f9b2bbc4b4cc7bc99ff64a9f",
    "preimage": "block:{\"at\":\"2026-11-07T00:19:13.573Z\",\"entry_count\":2,\"first_seq\":101,\"height\":30,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":102,\"merkle_root\":\"ebe5a6dc7105ddcf86481839b858271373105cb7eb7fa8aeaedf22326963d7ad\",\"prev_hash\":\"fe6320ef4c7d846b08b9263c0946dd11d6cda306406c291511204b80f74d1615\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:28:43.454Z",
      "updated_at": "2026-11-07T03:28:43.476Z",
      "bitcoin_block_height": 974874,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee70bc0995c1cbbf133168cd4b9de59b8c3228c0410c4fb5ee1deaef2ed2bb0e8dae781b37a490b4015311"
        },
        {
          "type": "bitcoin",
          "block_height": 974874,
          "merkle_root": "fa522f272a37cb03554d5be30f11a1564362627a0d248c198befb5a303c3a302"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:28:43.454Z",
      "updated_at": "2026-11-07T03:28:43.476Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee70bc9d99dae29ca622e5d7ef1849b12e357a3d6f9c67ce08fa43ed141550d329ced56f6b12ccc3669a70"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:28:43.454Z",
      "updated_at": "2026-11-07T03:28:43.476Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee70bcb80c74f5000b918b3b4947ea32e062445219b6766ea73e9cbc2c0c723b610a649be5b9a7a34c555f"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/30/anchor.ots",
  "how_to_verify": "Download the .ots proof and run `ots verify -d <block_hash> <file>.ots` with the OpenTimestamps client, which checks the Bitcoin attestation against Bitcoin block headers. The digest is the block hash: sha256 of digest.preimage, the text \"block:\" followed by the canonical block header, which is the same header the issuer signs."
}