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PDF content provenance

Content provenanceContent provenance: The record of where a piece of content came from and how it changed, carried with the content itself. for PDF files is a signed C2PA manifestC2PA manifest: The signed label itself: a small package inside a file that records who signed it, what they declared and how to check it. inside the file. Anyone can check who signed it and whether it changed, for free.

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A file holds a signed label in four layers: who signed it, what they declared including AI use, a fingerprint of the content, and a signature that seals them together.
The label sits inside the file. It names the signer, carries what they declared, fingerprints the content, and is sealed by a signature.
File
.pdf, MIME typeMIME type: The standard name for a file format, such as image/jpeg or audio/wav, that software uses to decide how to read a file. application/pdf
Where the label sits
Inside the file, in an attached file inside the PDF, marked as its C2PA label.
Standard
C2PAC2PA: The Coalition for Content Provenance and Authenticity: the group that publishes the open standard for content labels., the open standard for content labels.
Made for
Contracts, Reports, Legal filings, Research papers, Ebooks

What Encypher supports for PDF

  • SignSupported

    Encypher signs PDF files under C2PA 2.2 and 2.4.

  • CheckSupported

    Free in the browser checker, with no account.

  • Formal conformanceSupported

    Covered by our C2PA 2.2 conformance record.

How to check a PDF file

  1. Open the free checker.

    It runs in your browser. No account needed.

    Open the checker

  2. Add your PDF file.

    Drop it in or pick it from your device.

  3. Read the result.

    It shows who signed and what they declared, such as AI use. It also shows if the file changed.

Where the label sits in a PDF file

A PDF can carry attached files. The label rides as one of them.

In a PDF, the label is stored as a separate part attached to the document.
A PDF file keeps the label in an attached file inside the PDF, marked as its C2PA label.

PDF is the standard format for documents that must look the same everywhere. Contracts, reports, filings and papers go out as PDF.

What keeps the label on a PDF file

Four of the five answers a provenance check can give: Verified, Modified after signing, Issuer not recognized, and No provenance found. The fifth is Could not verify.
A check reports who signed and whether the content changed. It never says whether the content is true.
  • Sending and saving the file keep the label.
  • Changing the text after signing shows as a change.
  • Printing, scanning or exporting to another format makes a new file without the label.

For engineers

Show the technical detail
Embedding
JUMBF manifest store in an embedded file stream with AFRelationship C2PA_Manifest
Accepted MIME types
application/pdf
Signing versions
C2PA 2.2, 2.4
Verification
Any version. The checker reads any C2PA manifest it can parse, and the report names the version it checked against.
curl -X POST https://api.encypher.com/api/v1/sign/media \
  -H "Authorization: Bearer $ENCYPHER_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -F "file=@example.pdf" \
  -F "title=My PDF file" \
  -F "action=c2pa.created"

Support rows come from the live API capability matrix. Full reference: C2PA media types.

Keep reading

Create. Mark. Endure.

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