{
  "height": 27,
  "block_hash": "59dfdb3f7765d121ca0df789908ff56481878803d2c9a63d61985eec1f9dd9a2",
  "status": "confirmed",
  "bitcoin_block_height": 974874,
  "digest": {
    "alg": "sha256",
    "hex": "59dfdb3f7765d121ca0df789908ff56481878803d2c9a63d61985eec1f9dd9a2",
    "preimage": "block:{\"at\":\"2026-11-07T00:09:13.517Z\",\"entry_count\":2,\"first_seq\":96,\"height\":27,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":97,\"merkle_root\":\"94966137c2977b8c0428cb3c93b5b8c64495d11fd9918ac5a32aeb9a7bef7d4a\",\"prev_hash\":\"3990409f20027f925163ba4f65f69207641b9f97c1a41827127c694d165b8b65\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:18:43.452Z",
      "updated_at": "2026-11-07T03:18:43.476Z",
      "bitcoin_block_height": 974874,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee6e6408626e93a65aedbb27b22a57daddb4ed6f6733cac30fbf17396eca3762ae256ef36feef769db0558"
        },
        {
          "type": "bitcoin",
          "block_height": 974874,
          "merkle_root": "fa522f272a37cb03554d5be30f11a1564362627a0d248c198befb5a303c3a302"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:18:43.452Z",
      "updated_at": "2026-11-07T03:18:43.476Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee6e64c6b05f4f9e9586a2740a13984b23b86146e4eb8997dcaee3ab541a285f0475e9765d5ac664d46f52"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:18:43.452Z",
      "updated_at": "2026-11-07T03:18:43.476Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee6e64a7ce75717fd044050697c594fde84cac3a08f92bd81e336fe6654b651a4d5724eb8b0aeb9aeb1681"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/27/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."
}