{
  "height": 53,
  "block_hash": "fe2d87aae3979159b364742489bc3277e19f33c2679255d2b915178a96a7cce9",
  "status": "confirmed",
  "bitcoin_block_height": 974877,
  "digest": {
    "alg": "sha256",
    "hex": "fe2d87aae3979159b364742489bc3277e19f33c2679255d2b915178a96a7cce9",
    "preimage": "block:{\"at\":\"2026-11-07T01:19:15.048Z\",\"entry_count\":2,\"first_seq\":137,\"height\":53,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":138,\"merkle_root\":\"733ddf3fbab040b9aa8a4a3abbc92c7c23911055a869250a5b0c9693cf5ddc98\",\"prev_hash\":\"00fc8a3061b0683c65f0e44656372507dbffd3560bfb48d666ff55ab5d22e90e\",\"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": "6aee7eccf2c834d5c179fc7a0000bdc0c350796c992756cdccab635a4f8dba3d4ae85bf027e9d47876b4bf73"
        },
        {
          "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": "6aee7ecc68be2beff50ce849fb970859dfd6549734b914ed2133bee0369bc3e686352f5527900451fbe90641"
        },
        {
          "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": "6aee7ecbc65548af93632a931ea83d51f985604b804e8f363837f8cafe748f120a89c0494c86654c9fa04e77"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/53/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."
}