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Indelible's HTMLData Standard

Use the Indelible HTMLData Standard to embed structured quote and article authorship attestation metadata directly into your web pages.

At the top level of your article, whether it be an <article>, <main>, or even <body> tag, you must include the data-indelible="{}"1 attribute to indicate that the content within is part of an attestation.

To include or not to include

Indelible's HTMLData Standard is designed to be flexible, so you can choose to mark text as part of an attestation inclusively or exclusively.

Inclusive Marking

By marking specific elements (e.g., <p>, <h1>, <blockquote>, etc.) with the data-indelible-include attribute, you indicate that only those marked elements are part of the attestation. This allows you to selectively attest specific sections of your content, such as quotes or key paragraphs, while leaving other parts of the article, like advertisements and captions, outside the attestation.

Note

When using inclusive marking, any content that is not explicitly marked with data-indelible-include will be excluded from the attestation. This means that if you forget to mark a section of your article, it will not be included in the attestation, which could lead to incomplete attestations.

Exclusive Marking

By marking a parent element (e.g., <article>, <main>, or <body>) with the data-indelible attribute without manually specifying any data-indelible-include tags, you indicate that all content within that element is part of the attestation. This is the most common approach and is ideal for articles where the entire content is being attested. To exclude specific elements from the attestation, you can use the data-indelible-exclude attribute on those elements.

Note

Content from across different elements will be combined into a single string with only a single space separating them, and the resulting string will be attested as a whole.

Embedding Quotes

When your article quotes another attested work, you can embed the full cryptographic proof of that quote directly in the HTML using the data-indelible-quote attribute. Its value is the complete quote proof JSON for the quoted passage — allowing any reader or tool to verify the quote on-chain without needing a separate file.

Note

Verifiers will check that the text within the html element is contained at all, across chunk boundaries, in the quoted text in the proof file. Don't worry about keeping all of the text in a proof chunk visible to the user.

The data-indelible-quote Attribute

Add data-indelible-quote to any element that contains a quote (typically a <blockquote>, <span>, <q>, or <p>). Its value is a JSON object with the following fields:

Field Type Description
ipfsCid string The IPFS CID of the source article being quoted.
authority string The Ethereum address of the authority who attested the source article.
chainId number The chain ID of the network where the source attestation lives.
attestationIndex number The on-chain index of the source attestation.
proof array Merkle proof entries for the text chunks that make up this quote. Each entry has a value ([index, chunkText]) and a proof (array of sibling hashes).

The proof array contains one entry per chunk of the quoted text. Chunks are sorted by value[0] (the index) and joined to reconstruct the full quote. See Quote Verification for how the Merkle tree is built and how proofs are verified.

<blockquote
  data-indelible-quote='{
    "ipfsCid": "bafkreibv5ztp3bnp227ftsllzsi2q52qihnvlzqkv3sklklbosmtltg52m",
    "authority": "0xD77d245c4Fd75adb4eadFC4147469257061f06c1",
    "chainId": 11155111,
    "attestationIndex": 4,
    "proof": [
      {
        "value": ["40", "orridor through which a fifth of the world'\''s o"],
        "proof": [
          "0x68ee0e41adef1af681cdff20d9b4347acd58d8bed57ef0c1b7643c8e53c5a605",
          "0xf62d940314d0f1c38fec0fd4cde019b7e27d872734bdd0169c4c9b38a0500473",
          "0x434243c2b409f736ea2c09a8faa3ef717636d2624ffff6c29aa22650639425f3",
          "0xb3176681bc8ebcb4e79787a5a696304170e742bd962edd226a7be9e5877da06a",
          "0x2e7ea38575a882343ea2976c8430e99b95055a2bceba5fb662f282dcadf6d7a7",
          "0x1e0d0e6a974e0172e167da4d1afb1178513919b07bbc24f886d15918e77eba65"
        ]
      },
      {
        "value": ["41", "il and gas traveled before the war. On Sunday,"],
        "proof": [
          "0x099a98b82cbd8ec2b424230a24341a78b6995cc506743e637a9f5dcf4d9bf643",
          "0xb3b99a8f23d3b16338c6b71e5597ab9c019b01cd8f5a2db13e1075595a260747",
          "0x002468c15ffaf3a750a873adfd25c5a8ac57c8638f88f1f87db84129c5f97066",
          "0xdb03bb228b23ec63a8ed83efd00582621a399f062dc37d4b14a330b39c7825d7",
          "0xd7142eaa356344a94ca83fa839417ba049e59f0a7d51448f3079a1cdd0f72b7c",
          "0x1e0d0e6a974e0172e167da4d1afb1178513919b07bbc24f886d15918e77eba65"
        ]
      }
    ]
  }'
>
  …orridor through which a fifth of the world's oil and gas traveled before the war. On Sunday,…
</blockquote>

Proof files and inline attributes share the same format

The JSON you put in data-indelible-quote is structurally identical to the standalone quote proof file. You can generate one and use it both ways — embed it inline in the HTML and distribute it as a downloadable file for the Indelible verifier.

Quoted Elements and Inclusion/Exclusion

Elements with data-indelible-quote follow the same inclusion/exclusion rules as all other elements:

  • In exclusive mode, they are included in the attestation by default unless wrapped in a data-indelible-exclude element.
  • In inclusive mode, they must be explicitly marked with data-indelible-include to be part of the attestation.

Quotes that are excluded from the attestation are not included in the Merkle tree and will not appear in the proof file.

  1. The data-indelible attribute must contain a JSON object as specified in the Indelible Standard. ↩