Free C2PA Signing Tool

What is C2PA signing?

C2PA (Coalition for Content Provenance and Authenticity) is an open standard for attaching a cryptographically signed manifest to an image or video. The manifest records who created the file, when, with what tool, whether AI was involved, and any copyright or licensing information. Members include Adobe, Microsoft, Google, Truepic, BBC, and hundreds of other organisations. ForensicMark signs your images with a certificate that embeds this provenance data directly into the file.

C2PA is the technical standard underpinning Content Credentials — the specification was published by the Joint Development Foundation and is maintained by the C2PA Technical Working Group. Any C2PA-compatible viewer can independently verify a manifest signed by ForensicMark.

What does a C2PA manifest contain?

When you sign an image with the ForensicMark C2PA tool, the following fields are embedded in a cryptographically signed manifest and stored inside the image file:

• Author / creator name
• Copyright notice
• License (e.g. CC BY 4.0)
• Creator website
• AI-generated flag and tool name
• Creation timestamp and signing certificate
• Hash of the image content at the time of signing

How to sign an image with C2PA

Upload your image using the tool above, fill in the author and copyright fields, optionally flag the image as AI-generated, then download your signed file. The entire process takes under ten seconds and requires no account.

To verify the result immediately after signing, use the C2PA Verify Tool. You can also verify with Adobe's Content Credentials viewer at contentcredentials.org — both will display the manifest because C2PA is an open, interoperable standard.

For batch signing or pipeline integration, the ForensicMark API accepts up to 50 images per request and returns signed files with full manifest control. See the API documentation or request an API key.

Why C2PA alone is not enough

C2PA metadata is stored inside the file as XMP/JFIF data. It is readable by any C2PA viewer and provides strong cryptographic proof of authorship — but it is stripped by most social media platforms on upload. Instagram, X, Facebook, and TikTok all remove file metadata as part of their re-encoding pipeline.

If your image is screenshotted and re-uploaded, the C2PA manifest is gone entirely. The image becomes indistinguishable from an unsigned copy. This is the core limitation of any metadata-only provenance approach.

Pairing C2PA with an invisible watermark gives you complete coverage: the manifest travels with the original file through trusted channels, while the watermark survives re-encodes, screenshots, and social media uploads. Use the "Both" tab in the tool above to embed both in a single operation.

Who uses C2PA signing?

• Photographers and agencies building a verifiable chain of ownership before delivering client work
• AI image platforms disclosing AI-generated content, as required under EU AI Act Article 50
• News organisations verifying photojournalism authenticity before publication
• Stock platforms requiring provenance metadata on image submissions
• Enterprises building audit trails for synthetic content used in marketing materials
• Developers testing a C2PA signing pipeline before production deployment

The open-source C2PA tooling landscape

The C2PA working group published a reference implementation called c2patool — a command-line tool for signing and verifying C2PA manifests. The repository has since been archived as development moved to the newer c2pa-rs Rust library, which powers most production C2PA implementations today.

The command-line tools require a signing certificate, manifest JSON authoring, and local installation. ForensicMark wraps this complexity into a browser-based tool that requires nothing except the image you want to sign. For teams that need to integrate C2PA signing into an existing pipeline, the ForensicMark API provides the same capability over HTTP with no local tooling required.

How ForensicMark compares to other C2PA signing tools

Several commercial tools offer C2PA signing, primarily targeting enterprise customers with volume-based pricing. Most require account creation before any signing is possible.

ForensicMark is free for up to 15 C2PA signs per day with no account required. An API key unlocks unlimited signing, batch processing, and MCP server access for AI agent workflows. On-premise Docker deployment is available for data-sovereignty requirements.

C2PA signing for EU AI Act compliance

Article 50 of the EU AI Act requires providers of AI systems that generate synthetic content to mark that output in a machine-readable format. C2PA content credentials — specifically the AI-generated flag field — are a technically recognised approach for satisfying this disclosure requirement.

If you are using AI image generation in a commercial context, signing each output with a C2PA manifest that includes the AI-generated flag creates an auditable record of disclosure. ForensicMark's "Both" signing mode embeds the C2PA manifest alongside an invisible watermark in a single step, covering both the legal disclosure requirement and post-redistribution tracking in one operation.

Frequently Asked Questions

Learn more: What is C2PA? Content Credentials explained | EU AI Act watermarking requirements