{
  "what": "Bitcoin anchors for every block of this chain, stamped via OpenTimestamps.",
  "why": "After an anchor confirms, nobody (the operator included) can rewrite the blocks beneath it. Only (index, hash, sealedAt, url) is stamped; no content leaves the library.",
  "howToVerify": "Guided, no command line: open /verify-anchor/{index} for any block and follow the three steps. Or by hand: download a statement and its proof side by side, then run: ots verify block-NNNNNN.json.ots — the open OpenTimestamps client checks it against Bitcoin with no trust in this server. No command line needed either: drag both files onto https://opentimestamps.org and it shows the state (pending, or the confirming Bitcoin block). The statement itself carries the cross-reference url back to /block/N here.",
  "anchoringEnabled": true,
  "anchors": [
    {
      "index": 0,
      "hash": "6095729018b0c57a1e7b3211f718fcd4723e1a3add0543c9b3ec0ab0caad9a1d",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000000.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000000.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/0"
    },
    {
      "index": 1,
      "hash": "aece541c352d41c4db97761286747f90ead8952f567d8988664ac8685c556385",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000001.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000001.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/1"
    },
    {
      "index": 2,
      "hash": "22c7e308735624a6358e279f46cbeeda3250d860bbbab3a3b7ab2ae0e2324cdc",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000002.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000002.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/2"
    },
    {
      "index": 3,
      "hash": "a2c80c6c562a61feaf8e4d2b3c72182142936f3f22a91dcfd491b0509d4da4ea",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000003.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000003.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/3"
    },
    {
      "index": 4,
      "hash": "b50e7746a90cc01fe27b8b0a14308d3faf284d34ac31882fee13e4be1e34aba2",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000004.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000004.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/4"
    },
    {
      "index": 5,
      "hash": "fbecf49d40817e7e541ed1299b30a67070e0e8d23dbc68d427d768ac61c86568",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000005.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000005.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/5"
    },
    {
      "index": 6,
      "hash": "f3fc5ca7d75dd682e47d91b005412c3b027c52b93d1ac3a28875ddae7f9e6a0f",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000006.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000006.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/6"
    },
    {
      "index": 7,
      "hash": "80e8569e174614984280095e2f49b150211ca4204019712621faff5bb03f31e5",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000007.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000007.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/7"
    },
    {
      "index": 8,
      "hash": "8850d57334e53d8aaee8868e6c5b6694f90606707a785ca2f372bab20f56384f",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000008.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000008.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/8"
    },
    {
      "index": 9,
      "hash": "bec4401186fe653fd00ecbb9ac0ba583d078ed99522ec0141c8ba188b4230c96",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000009.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000009.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/9"
    },
    {
      "index": 10,
      "hash": "453e11b61bde987d8b5e8f79aa4f853fb3e066718f1afb54725af86d2d44c80e",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000010.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000010.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/10"
    },
    {
      "index": 11,
      "hash": "0b464664dc6b1744657b464e57da0bd2d9a740c9d72b52d399c92093779ed0e2",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000011.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000011.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/11"
    },
    {
      "index": 12,
      "hash": "9294dcf63727b2a91daad4d31d27ed5b0e952ca68675c51f5bc2399c8945050a",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000012.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000012.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/12"
    },
    {
      "index": 13,
      "hash": "a0e15ad0dff2fcb342ffa24c5abd13c7107078dcdf201441f67bc5515a381b3a",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000013.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000013.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/13"
    },
    {
      "index": 14,
      "hash": "b4e828fa4efa118445503cd689ae2ff0df464802329d3e176d8f63f01fff2dae",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000014.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000014.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/14"
    },
    {
      "index": 15,
      "hash": "c88a4092dbc666ff68232ffc972294386d51dd9be82dd442379bed3ff03feb94",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000015.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000015.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/15"
    },
    {
      "index": 16,
      "hash": "c573fbf8e42d56cf06c6ca01c7790dc9d9e4914ae26e0882426e9e169635a027",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000016.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000016.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/16"
    },
    {
      "index": 17,
      "hash": "a38cb83b51b1df08ad8ed35621fcb0ad05ecfb1f2dd5ac351c33239d291a824e",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000017.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000017.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/17"
    },
    {
      "index": 18,
      "hash": "5c4faaaa8289cfb0d870a16c8dffa111575d1eadb28b3941118b50a840d5395d",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000018.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000018.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/18"
    },
    {
      "index": 19,
      "hash": "f475e70e27b9e5cc33345a5836d2cb59227450632b36a80f74af6fe26f1fe47f",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000019.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000019.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/19"
    },
    {
      "index": 20,
      "hash": "9895f721ec25ca7560e60c14de9bc9beabdcef3ae08ec8921f81da140a26d7dd",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000020.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000020.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/20"
    },
    {
      "index": 21,
      "hash": "577330b89d10622a3ceb995c0b67713af8a045e1acf7aebba8a744b153cec923",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000021.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000021.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/21"
    },
    {
      "index": 22,
      "hash": "1e5ce8b7ba29ce9c31d6e600f32b36f5983e6a8d0930ff107ea5883b4613f094",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000022.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000022.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/22"
    },
    {
      "index": 23,
      "hash": "4577c935aae0d5dda03775c24ed74d46c95d77d75223d797d4c442ce91096f08",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000023.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000023.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/23"
    },
    {
      "index": 24,
      "hash": "6bf84064d2bc5a8bbfe9ce31906d9611d6852c7477912bfce315d49116134e1c",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000024.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000024.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/24"
    },
    {
      "index": 25,
      "hash": "e2a03741055d11cfaef8d451189f9bc1abf0cea58a1243b5724484162aee9fd4",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000025.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000025.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/25"
    },
    {
      "index": 26,
      "hash": "ce3f41ebdc27f8277eb02883093d43c1aa03a30f491b3f74fc4f052fa5ec2a72",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000026.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000026.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/26"
    },
    {
      "index": 27,
      "hash": "56bfdf3fe3c7ba66dfcfe72ddebdb4738db1a47957839b6ebabd2c8017ace448",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000027.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000027.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/27"
    },
    {
      "index": 28,
      "hash": "bf3e5f73e64c1ae7a6c0905320e7f979b1b593624d0974916e73eb878721267f",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000028.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000028.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/28"
    },
    {
      "index": 29,
      "hash": "9e99813b4386ffa28226d06e00b58333efc943b288fed97c59070f6797b99153",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000029.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000029.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/29"
    },
    {
      "index": 30,
      "hash": "157a1f5c1a1c92f3db937716ce41cd4e284079c37336d15730b8678097cb5fe9",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000030.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000030.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/30"
    },
    {
      "index": 31,
      "hash": "2b3bc80bf9fce04a32c1362518157c00d013ce4da263ba8e535a5d9f0bfa57b6",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000031.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000031.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/31"
    },
    {
      "index": 32,
      "hash": "1399a95b3921399893aa6afe4ed7858c1280262924011114951c85ff03bd06c9",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000032.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000032.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/32"
    },
    {
      "index": 33,
      "hash": "aca3a05e43508b5426f0c3c4d77757c8e72dee0457afbede30433853e4f3dfda",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000033.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000033.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/33"
    },
    {
      "index": 34,
      "hash": "37fd9341d9c895dba82dd747fc4b9341c8f35dcd929a6096b0cb66dd74b318ac",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000034.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000034.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/34"
    },
    {
      "index": 35,
      "hash": "1ba2edf671d968f2c2656d4c067cec6e135d50921ebee81ceda39c174b7346d4",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000035.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000035.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/35"
    },
    {
      "index": 36,
      "hash": "439a5652e2f7df157f665003c608d5f103bb0b45094a035bf44bccaee4496980",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000036.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000036.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/36"
    },
    {
      "index": 37,
      "hash": "dbe13451ca29697dc6fc41f5f033bf41bc252b29ee88e87571ea2b6160377859",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000037.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000037.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/37"
    },
    {
      "index": 38,
      "hash": "96f80ae77789a942ff4389cf67f5d769e2469726d5d6af063219c9c7a27299e0",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000038.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000038.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/38"
    },
    {
      "index": 39,
      "hash": "d70b9dff257f5272e5e24324a4e36d8ffdb0cce436bf55779f26865e9dc35394",
      "status": "anchored",
      "bitcoinBlocks": [
        966087
      ],
      "statementUrl": "https://heartwoodlibrary.org/api/anchors/block-000039.json",
      "proofUrl": "https://heartwoodlibrary.org/api/anchors/block-000039.json.ots",
      "blockUrl": "https://heartwoodlibrary.org/block/39"
    }
  ]
}