Technical

C2PA Manifest Deep Dive: Understanding Every Component

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C2PA Manifest Deep Dive: Understanding Every Component

What is a C2PA Manifest?

A C2PA manifest is a cryptographically signed data structure embedded within a media file. It's the core data container that carries all provenance information about the content.

Manifest Components

1. Claim

The claim is the central element that ties everything together:

  • Claim Generator — Identifies the software that created the manifest
  • Title — Human-readable name of the asset
  • Format — MIME type of the asset (e.g., image/jpeg)
  • Instance ID — Unique identifier for this specific version

2. Assertions

Assertions are individual claims about the content. Common assertion types:

  • c2pa.actions — Actions performed (created, edited, resized, etc.)
  • c2pa.hash.data — Hash of the asset data for integrity verification
  • stds.exif — EXIF metadata embedded within C2PA
  • c2pa.thumbnail.claim.jpeg — Thumbnail of the asset
  • stds.schema-org.CreativeWork — Schema.org metadata

3. Digital Signature

The signature provides cryptographic proof:

  • Issuer — Certificate authority that issued the signing certificate
  • Signing Time — When the manifest was signed
  • Algorithm — Cryptographic algorithm used (e.g., ES256, PS256)
  • Certificate Chain — X.509 certificate chain for verification

4. Ingredients

Ingredients reference source materials used to create or modify the content:

  • Title — Name of the source asset
  • Format — MIME type of the ingredient
  • Relationship — How this ingredient relates (parentOf, componentOf)
  • Hash — Cryptographic hash to verify the ingredient

5. Validation Status

Reports on the integrity of the manifest:

  • Success — Signature and data integrity verified
  • Failure — Manifest has been tampered with or signature is invalid
  • Info — Additional validation notes

Manifest Store

A file can contain multiple manifests in a manifest store, creating a provenance chain. Each edit that preserves C2PA adds a new manifest linked to the previous one through ingredients.

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