{
  "height": 72,
  "block_hash": "b98380f0c149bfaaaf331e4e30cf9a3a19ff7f901a04cc09fc7a246273d8ee98",
  "status": "confirmed",
  "bitcoin_block_height": 974880,
  "digest": {
    "alg": "sha256",
    "hex": "b98380f0c149bfaaaf331e4e30cf9a3a19ff7f901a04cc09fc7a246273d8ee98",
    "preimage": "block:{\"at\":\"2026-11-07T02:04:15.214Z\",\"entry_count\":2,\"first_seq\":166,\"height\":72,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":167,\"merkle_root\":\"18b259e036feb80551a63414cf4accfcf134cb7fa7e458a96602e55b77b7dc3a\",\"prev_hash\":\"35b8ce208d809f5793c26d9663a874b16b31795cad7000ba6f90311dc805eedf\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T02:08:43.462Z",
      "updated_at": "2026-11-07T04:08:43.478Z",
      "bitcoin_block_height": 974880,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee882e9e811e4cadbeb578d58e950ba988e80a983dd30e40ac7c22d66c1f46e0fa3c96c1f2c03b904f5424"
        },
        {
          "type": "bitcoin",
          "block_height": 974880,
          "merkle_root": "e20917e92c25ba0bebbc60b5b7fe48f0ee84f05c3eb4987c3107d249f2c7113d"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T02:08:43.462Z",
      "updated_at": "2026-11-07T04:08:43.478Z",
      "bitcoin_block_height": 974883,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee882ecc5b0fb6c23c48250fb32994dec32e6ff3fe0b44fd75a384ce72f9c210a9cc4dec061aab87fb7ad8"
        },
        {
          "type": "bitcoin",
          "block_height": 974883,
          "merkle_root": "79abb9dd33baad0a1ff37045cc779f6fe1b133a7037999fbd2c996ad78e43b90"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "pending",
      "submitted_at": "2026-11-07T02:08:43.462Z",
      "updated_at": "2026-11-07T02:08:43.462Z",
      "bitcoin_block_height": null,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee882e62b3f3efb4b15c50e658c664cd671098d019dd4bd4187db08bbf01367db278ea3edda3428cddbff6"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/72/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."
}