{
  "height": 20,
  "block_hash": "54864523a5aec2dbc8927008def58b6fbeba4bd222f564f24f5e6687ee3a735f",
  "status": "confirmed",
  "bitcoin_block_height": 974874,
  "digest": {
    "alg": "sha256",
    "hex": "54864523a5aec2dbc8927008def58b6fbeba4bd222f564f24f5e6687ee3a735f",
    "preimage": "block:{\"at\":\"2026-11-06T23:44:30.420Z\",\"entry_count\":1,\"first_seq\":85,\"height\":20,\"key_id\":\"key_a521921c2ba20669\",\"last_seq\":85,\"merkle_root\":\"e3ebb83993e594a13ca5de7dd35e5b236e015671075ae1b497442376c4451afd\",\"prev_hash\":\"5de41f7e9becddd0ca9af3e2c9f70630c3962415cf83f6fe30966bc151b7227d\",\"v\":1}"
  },
  "calendars": [
    {
      "calendar": "https://a.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-06T23:53:03.605Z",
      "updated_at": "2026-11-07T02:58:43.471Z",
      "bitcoin_block_height": 974874,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://alice.btc.calendar.opentimestamps.org",
          "commitment": "6aee6861f0e47843f934ecb2287414c423bebe511fe28e5d70598c86b565b6b607bf6e8cde6246fb7fceeba6"
        },
        {
          "type": "bitcoin",
          "block_height": 974874,
          "merkle_root": "fa522f272a37cb03554d5be30f11a1564362627a0d248c198befb5a303c3a302"
        }
      ]
    },
    {
      "calendar": "https://b.pool.opentimestamps.org",
      "status": "confirmed",
      "submitted_at": "2026-11-06T23:53:03.605Z",
      "updated_at": "2026-11-07T03:58:43.477Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://bob.btc.calendar.opentimestamps.org",
          "commitment": "6aee686350dfe5b3ccca42569c475915ac23ff6cec283be2d8fb26cd248db765224e0c44ca3523608d06ab08"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    },
    {
      "calendar": "https://finney.calendar.eternitywall.com",
      "status": "confirmed",
      "submitted_at": "2026-11-06T23:53:03.605Z",
      "updated_at": "2026-11-07T03:58:43.477Z",
      "bitcoin_block_height": 974877,
      "attestations": [
        {
          "type": "pending",
          "uri": "https://finney.calendar.eternitywall.com",
          "commitment": "6aee6861f95ac7ab6de597d9317721ee086345963fec90e77ab396b790af0cf771e1bdffc6b8ff143b732ea0"
        },
        {
          "type": "bitcoin",
          "block_height": 974877,
          "merkle_root": "dee625f48434576e86df10e80f2912b1c31b96672232e47e103806c1faef5814"
        }
      ]
    }
  ],
  "proof_url": "https://www.a2ally.com/v1/ledger/blocks/20/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."
}