{
  "height": 57,
  "block_hash": "bf61797fbf9f9c252933cd56bdbb3a6988158482ebfa30386bdd53760d690014",
  "status": "confirmed",
  "bitcoin_block_height": 974877,
  "digest": {
    "alg": "sha256",
    "hex": "bf61797fbf9f9c252933cd56bdbb3a6988158482ebfa30386bdd53760d690014",
    "preimage": "block:{\"at\":\"2026-11-07T01:29:15.101Z\",\"entry_count\":2,\"first_seq\":144,\"height\":57,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":145,\"merkle_root\":\"6d154c53fee9ad16361781d58524f0ed2c7fb170c8036a85a84d4d6398d6f42d\",\"prev_hash\":\"e83386a58cb7d7a1d64817e541f8d0784e6ae7911e6a015bd9d016d53859421f\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:38:43.460Z",
      "updated_at": "2026-11-07T04:38:43.483Z",
      "bitcoin_block_height": 974880,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee81240feb12dac1c1ba6839930d64f6a0b27090475dd120f341d27f373dec4333f77befe27274af252fe8"
        },
        {
          "type": "bitcoin",
          "block_height": 974880,
          "merkle_root": "e20917e92c25ba0bebbc60b5b7fe48f0ee84f05c3eb4987c3107d249f2c7113d"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:38:43.460Z",
      "updated_at": "2026-11-07T04:38:43.483Z",
      "bitcoin_block_height": 974883,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee812401959da6d5be5b6cc0d0de26a248b05554d26182ab729d722456e1fdb622ddde243ed34dabba605a"
        },
        {
          "type": "bitcoin",
          "block_height": 974883,
          "merkle_root": "79abb9dd33baad0a1ff37045cc779f6fe1b133a7037999fbd2c996ad78e43b90"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:38:43.460Z",
      "updated_at": "2026-11-07T03:38:43.477Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee81243bcdc5e9f537807e64d64f81ffb33f64dc36eae5af4280d651122467707b9881d2c386cb17c10059"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/57/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."
}