Manifest

The Manifest establishes a hard binding between the asset and its provenance metadata. It contains a cryptographic hash of the asset, ensuring that any subsequent modification to the pixel data or audio waveform invalidates the signature. This creates a mathematically verifiable link, proving that the assertions contained within the Manifest were intended for that exact file and no other.

A Manifest acts as a structured container for multiple signed assertions. Each assertion is a discrete, verifiable claim about the asset, such as:

• Creative Assertions: Author name, creation date, copyright.
• Action Assertions: Edits performed (e.g., cropped, color-adjusted).
• Thumbnail Assertions: A trusted visual preview. These assertions are serialized in a standardized format (like JSON-LD) for machine-readability.

Manifests explicitly track the lineage of composite works through an ingredient list. If an image is created by combining multiple source files, each source's Manifest becomes an ingredient. This creates a directed acyclic graph of provenance, allowing a validator to recursively walk back through every component asset to verify the complete provenance trail of the final composite.

The integrity of the entire Manifest is protected by a digital signature generated using the signer's private key. Verification involves:

1. Checking the signature against the signer's public certificate.
2. Validating the certificate chain back to a trusted root Certificate Authority.
3. Confirming the asset hash matches the current bitstream. This process ensures the Manifest has not been tampered with since it was signed.

The C2PA specification supports two storage models for the Manifest:

• Embedded: The JUMBF-encoded Manifest is injected directly into the file's metadata (e.g., JPEG, PNG, MP4), ensuring it travels with the asset.
• Remote: The Manifest is stored on a cloud service, and the asset contains a hashlink URL pointing to it. This allows for dynamic updates but requires network access for verification.

When a legitimate edit is made (e.g., a newsroom crops a photo), a new Manifest is generated. This new Manifest:

• Includes the previous Manifest as an ingredient.
• Contains a new action assertion describing the edit.
• Is signed with the editor's credential. This creates a transparent, auditable chain of custody where any unauthorized alteration breaks the chain and is immediately detectable.

The fundamental building block within a manifest. A signed assertion is a cryptographically signed statement made by an entity about a content asset. Examples include:

• Creative Work Assertion: Declares the author and creation date
• Thumbnail Assertion: Provides a verifiable visual reference
• Training Data Assertion: Claims whether AI was used in generation Each assertion is individually verifiable without unpacking the entire manifest.

A method of embedding the manifest directly into the bitstream of the asset file itself. Unlike sidecar metadata files that can be lost during transfer, hard binding ensures the provenance data is cryptographically inseparable from the content. For JPEG files, this uses the JUMBF (JPEG Universal Metadata Box Format) standard to store the manifest within the image's binary structure.

A sequential, verifiable record of every actor and process that contributed to an asset's creation. Each link in the chain contains:

• The identity of the actor (signer)
• The specific action performed (capture, edit, publish)
• A cryptographic signature over the previous state This creates a directed acyclic graph of provenance that auditors can traverse from final output back to original capture.

The user-facing implementation of a C2PA manifest. Often described as a 'digital nutrition label,' it surfaces the cryptographically verified attribution and edit history in a human-readable format. Platforms like Adobe Photoshop and Microsoft Designer display these credentials as a pin icon, allowing consumers to inspect the provenance trail of any compliant asset before trusting it.

An append-only, publicly auditable ledger that records manifest signatures. By publishing signed assertions to a transparency log, content creators enable third-party monitoring of their provenance claims. This prevents backdating or silent modification of manifests, as any observer can detect discrepancies between a claimed signature timestamp and the log's immutable record.