{
  "height": 51,
  "block_hash": "354d1b336ec3c825611b1cc3bd391d78f0a94c13a5c862b999c5021b9ccd6dad",
  "status": "confirmed",
  "bitcoin_block_height": 974874,
  "digest": {
    "alg": "sha256",
    "hex": "354d1b336ec3c825611b1cc3bd391d78f0a94c13a5c862b999c5021b9ccd6dad",
    "preimage": "block:{\"at\":\"2026-11-07T01:14:15.031Z\",\"entry_count\":2,\"first_seq\":134,\"height\":51,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":135,\"merkle_root\":\"06df7803efb1ca86cc1726b26950a765f803effba3604c3e642b24780840e33e\",\"prev_hash\":\"8ba66840c7d113393b43837d34e9ef49786ec753a7f93f95c85fbbe19438409e\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:18:43.458Z",
      "updated_at": "2026-11-07T03:18:43.476Z",
      "bitcoin_block_height": 974874,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee7c75e1da403ef29160c6c03b1f86000b168eba4d5c441accf852f07a176b6270e0e3ff560c63209bc4b5"
        },
        {
          "type": "bitcoin",
          "block_height": 974874,
          "merkle_root": "fa522f272a37cb03554d5be30f11a1564362627a0d248c198befb5a303c3a302"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:18:43.458Z",
      "updated_at": "2026-11-07T03:18:43.476Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee7c76566901f74bd4e874195fb7e3e31c737c081cc0d25da3460db5ee5105f5d35fd3763c32c44d63b39a"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-07T01:18:43.458Z",
      "updated_at": "2026-11-07T03:18:43.476Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee7c76090f8bed75763326d94d06b50bc371dbb393f5396696fc181df79976dd5fe508e8da85f632e4f378"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/51/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."
}