{
  "height": 55,
  "block_hash": "592285687a8cfa9dd1a3b74e35bd5084e1a34d14fa9436e72835227155faceff",
  "status": "confirmed",
  "bitcoin_block_height": 974877,
  "digest": {
    "alg": "sha256",
    "hex": "592285687a8cfa9dd1a3b74e35bd5084e1a34d14fa9436e72835227155faceff",
    "preimage": "block:{\"at\":\"2026-11-07T01:24:15.074Z\",\"entry_count\":3,\"first_seq\":140,\"height\":55,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":142,\"merkle_root\":\"508012dbd256a7b460144fe8bea9e53720b872fb742a793077f40827faa3c338\",\"prev_hash\":\"fecec13e7488c03b673de1e3b6a93fe55ec4b217003bb366fa7cf4c2296b4b80\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:28:43.459Z",
      "updated_at": "2026-11-07T04:28:43.481Z",
      "bitcoin_block_height": 974880,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee7ece237db37de9a9501361a5a97afb69d6cf646def9ba95e2dd8518979846b3ff4688345a19e916f09c5"
        },
        {
          "type": "bitcoin",
          "block_height": 974880,
          "merkle_root": "e20917e92c25ba0bebbc60b5b7fe48f0ee84f05c3eb4987c3107d249f2c7113d"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:28:43.459Z",
      "updated_at": "2026-11-07T04:28:43.481Z",
      "bitcoin_block_height": 974883,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee7ece3c86dafc37d5c0559c2ac833e0d7beded8ab5d2535d46fe161f799ce713b1e7533dea8ecdaebe3e2"
        },
        {
          "type": "bitcoin",
          "block_height": 974883,
          "merkle_root": "79abb9dd33baad0a1ff37045cc779f6fe1b133a7037999fbd2c996ad78e43b90"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:28:43.459Z",
      "updated_at": "2026-11-07T03:28:43.476Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee7ecd6207bf50b5382c15efe885ff40de4973a9fb1069241bc9a8fe23500460848d3b57f3977b7af4997c"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/55/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."
}