{
  "height": 81,
  "block_hash": "b1dcac2875f4798ed4894f224ad244fa3fb764c62444c2522b72d734722cc9f8",
  "status": "confirmed",
  "bitcoin_block_height": 974880,
  "digest": {
    "alg": "sha256",
    "hex": "b1dcac2875f4798ed4894f224ad244fa3fb764c62444c2522b72d734722cc9f8",
    "preimage": "block:{\"at\":\"2026-11-07T02:26:00.279Z\",\"entry_count\":1,\"first_seq\":181,\"height\":81,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":181,\"merkle_root\":\"594c06cccb129cd50879fd7726333768c6ff1e70f4cafc275f273e8f2f70a0ad\",\"prev_hash\":\"c856b86c289adb02fc6f6f13c057c7673e60ebe8a159bc1dc462c7d683a4ae5d\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T02:28:43.466Z",
      "updated_at": "2026-11-07T04:28:43.481Z",
      "bitcoin_block_height": 974880,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee8cdfca0cf22e67457c6f7308e8f154d59042892e9edd0e5fbaa2a4122b6afc8fad43fdaac85532af4d89"
        },
        {
          "type": "bitcoin",
          "block_height": 974880,
          "merkle_root": "e20917e92c25ba0bebbc60b5b7fe48f0ee84f05c3eb4987c3107d249f2c7113d"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T02:28:43.466Z",
      "updated_at": "2026-11-07T04:28:43.481Z",
      "bitcoin_block_height": 974883,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee8cdf2ee29325d06bc2134a2fd477ffcbcf8a64932a21f228c3236d6cd2f8fcdec25bcef328b09e019641"
        },
        {
          "type": "bitcoin",
          "block_height": 974883,
          "merkle_root": "79abb9dd33baad0a1ff37045cc779f6fe1b133a7037999fbd2c996ad78e43b90"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "pending",
      "submitted_at": "2026-11-07T02:28:43.466Z",
      "updated_at": "2026-11-07T02:28:43.466Z",
      "bitcoin_block_height": null,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee8cdf9b846cad3836d749da5e4c11db0eae695bd3f4c896acc13a6ee46fdeab2f89a4924867fb51648ab4"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/81/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."
}