{
  "height": 40,
  "block_hash": "45f2b1657391f919af26bfca46d1f95b5e86adeaa6bde2d2b925a00513e64194",
  "status": "confirmed",
  "bitcoin_block_height": 974874,
  "digest": {
    "alg": "sha256",
    "hex": "45f2b1657391f919af26bfca46d1f95b5e86adeaa6bde2d2b925a00513e64194",
    "preimage": "block:{\"at\":\"2026-11-07T00:47:29.895Z\",\"entry_count\":1,\"first_seq\":118,\"height\":40,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":118,\"merkle_root\":\"e45b31970ae41763530d6b59f937730396a65ac5c65883f7233c34c8e47e71de\",\"prev_hash\":\"0f5e84630e9a7aa1d1a4b6b39dba6ee5d5a0dfe1a7c2237770db5c779a3d7eaf\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:48:43.456Z",
      "updated_at": "2026-11-07T02:48:43.467Z",
      "bitcoin_block_height": 974874,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee7570e1c851dd212ec4242c0734a4d727b55016995538afe70016520a78a3ca4f3387bee74a4a7d329c42"
        },
        {
          "type": "bitcoin",
          "block_height": 974874,
          "merkle_root": "fa522f272a37cb03554d5be30f11a1564362627a0d248c198befb5a303c3a302"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:48:43.456Z",
      "updated_at": "2026-11-07T03:48:43.477Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee7570d456207be80995bd3f246849abfbd81385e8addd99a85e87d4df3bca674fff77b76d93fd3c900357"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-07T00:48:43.456Z",
      "updated_at": "2026-11-07T03:48:43.477Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee75707b4e5da935bc8280973edbef601a0e99db0c3ce368fd5dde19952cda25c5bd53463a9554a1d36365"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/40/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."
}