{
  "height": 37,
  "block_hash": "a494994c67d1df4b5867a84e92729587611b3add380cef74ecca7d35414fe2d4",
  "status": "pending",
  "bitcoin_block_height": null,
  "digest": {
    "alg": "sha256",
    "hex": "a494994c67d1df4b5867a84e92729587611b3add380cef74ecca7d35414fe2d4",
    "preimage": "block:{\"at\":\"2026-11-07T00:41:44.367Z\",\"entry_count\":1,\"first_seq\":114,\"height\":37,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":114,\"merkle_root\":\"4c043ecb2297b329194d66d9059056f4d87e9c8534660111129496cb63d36a92\",\"prev_hash\":\"dc301ccd2bc773dcb2e042e116a2938de9d1412a2cd5a5a262aa1d12f17642d2\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "pending",
      "submitted_at": "2026-11-07T00:48:43.456Z",
      "updated_at": "2026-11-07T00:48:43.456Z",
      "bitcoin_block_height": null,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee756d29e5de6d94d2e53df4814056ddf895e5678c47ed4724301ebdef9e234b299197898398b0c1898851"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "pending",
      "submitted_at": "2026-11-07T00:48:43.456Z",
      "updated_at": "2026-11-07T00:48:43.456Z",
      "bitcoin_block_height": null,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee756d73de0293afa7f816ea52d2fffde28f5fdaba360b2871cd9f47166aa3ca623e6146fa30eb08d8c573"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "pending",
      "submitted_at": "2026-11-07T00:48:43.456Z",
      "updated_at": "2026-11-07T00:48:43.456Z",
      "bitcoin_block_height": null,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee756d51a18485d7d047560e7324c980e76b3ad82429fc9c28863f16049957e9de8c6ce9c78c333f490c7d"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/37/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."
}