{
  "height": 4,
  "block_hash": "c6fbc96265961f34d7f5286ed4bb91d7817caa31c35fe928cd7f13593b1258e6",
  "status": "confirmed",
  "bitcoin_block_height": 974874,
  "digest": {
    "alg": "sha256",
    "hex": "c6fbc96265961f34d7f5286ed4bb91d7817caa31c35fe928cd7f13593b1258e6",
    "preimage": "block:{\"at\":\"2026-11-06T22:25:18.455Z\",\"entry_count\":2,\"first_seq\":52,\"height\":4,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":53,\"merkle_root\":\"d8ea9f9940fcfbe4c228dfb89819360a9c0021a3ebeb8e70b025ec17f4ef56d5\",\"prev_hash\":\"096a91168ec14cf7848b7248874f8aaa8083a2957c927a05a278f648e4720469\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-06T22:34:47.904Z",
      "updated_at": "2026-11-07T03:08:43.475Z",
      "bitcoin_block_height": 974874,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee5609f0e23c59855d8154a1e637feb4528583311518e752d70e996b456c61a9325006dfde327297a7c215"
        },
        {
          "type": "bitcoin",
          "block_height": 974874,
          "merkle_root": "fa522f272a37cb03554d5be30f11a1564362627a0d248c198befb5a303c3a302"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-06T22:34:47.904Z",
      "updated_at": "2026-11-07T03:08:43.475Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee5608b45b5c28560ae9aae49e60a6d89d485a8279b87af7967c5303f8e7dd97596a4a9b753ed79ec66ed8"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-06T22:34:47.904Z",
      "updated_at": "2026-11-07T03:08:43.475Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee5608d2246ec4e311b56461d08975389b34c6765be36e7d895a8f1b75e437728c9a8595140b0a197325e1"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/4/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."
}