{
  "height": 73,
  "block_hash": "bb7eb2517d16ee5b4f074e5b76bb53621ddcf711d379f9357beb3d43cfad04f0",
  "status": "confirmed",
  "bitcoin_block_height": 974880,
  "digest": {
    "alg": "sha256",
    "hex": "bb7eb2517d16ee5b4f074e5b76bb53621ddcf711d379f9357beb3d43cfad04f0",
    "preimage": "block:{\"at\":\"2026-11-07T02:07:15.221Z\",\"entry_count\":1,\"first_seq\":168,\"height\":73,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":168,\"merkle_root\":\"312c545889270f9f651524a2b60b7c6acbbfee049e5ccb01c3596ccb2c1c34f1\",\"prev_hash\":\"b98380f0c149bfaaaf331e4e30cf9a3a19ff7f901a04cc09fc7a246273d8ee98\",\"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": "6aee882f3507f65fb5233b33b267ba8c785fb45ed3557067073160285f77a9eb06d53a78d8470df91426d1e6"
        },
        {
          "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": "6aee882f4ae1ac2963604ad411a29bffdcdfe3ccd1a7965b271a25bd3f4e04432a4ce025cfbf0e25bc080ceb"
        },
        {
          "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": "6aee882fd5c77a5b17a076ef80b41cd8d721f573a27e10bf6e3a4ff1a225f9c916ad6699fb8efba44cf8bc39"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/73/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."
}