{
  "height": 17,
  "block_hash": "4a4feeae5a87219f3cc4b6ee1e93e2b95f307a1d651e5b8f9b9a1803e483964e",
  "status": "confirmed",
  "bitcoin_block_height": 974874,
  "digest": {
    "alg": "sha256",
    "hex": "4a4feeae5a87219f3cc4b6ee1e93e2b95f307a1d651e5b8f9b9a1803e483964e",
    "preimage": "block:{\"at\":\"2026-11-06T23:33:33.693Z\",\"entry_count\":2,\"first_seq\":79,\"height\":17,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":80,\"merkle_root\":\"21ce076f03b40a51febf5232b6847a2e46a441bb712a7237e55eb6f331d7924d\",\"prev_hash\":\"550d7c29735d4760a6a2ca798a688c005f925bb4d94fedf379925c1471472595\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-06T23:43:03.604Z",
      "updated_at": "2026-11-07T02:48:43.467Z",
      "bitcoin_block_height": 974874,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee6608eb281f8df37fec512554e6488397dfef2eb22629503653c49e37578d2cef4f18b3a7e265e380be1b"
        },
        {
          "type": "bitcoin",
          "block_height": 974874,
          "merkle_root": "fa522f272a37cb03554d5be30f11a1564362627a0d248c198befb5a303c3a302"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-06T23:43:03.604Z",
      "updated_at": "2026-11-07T03:48:43.477Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee660898cb81c47369a9db3ee336af8ad7da3f41f28da4aaaae745f50da45d993e6525e906602159c33027"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-06T23:43:03.604Z",
      "updated_at": "2026-11-07T03:48:43.477Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee6607a7a7a935525a8e186d0f07df99ed70de87d9caa3dbb681fdea823cfd4c209fd5849c3d510b32bd62"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/17/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."
}