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Glossary

Soft binding: finding the manifest after the file lost it

A soft binding, in C2PA terms, is a way to associate content with its manifest without relying on embedded metadata, using an invisible watermark or a content fingerprint recorded in a soft-binding assertion, so that a stripped copy can be matched back to the manifest held elsewhere.

Definitions and isGenAI behaviour as of October 2026. Updated .

See the term in a real reportFrequently asked questions
Code-drawn illustration for Soft binding

Illustration · PNG file

  1. Signature + IHDR
  2. iTXt XML:com.adobe.xmprecord
  3. tEXt parameters
  4. tEXt prompt / workflow
  5. tEXt invokeai_metadata
  6. eXIf
  7. caBX C2PA manifest
  8. IDAT pixels
  9. IEND

AI source type declared

The file labels itself as AI-made.

IPTC DigitalSourceType such as trainedAlgorithmicMedia is read from XMP and shown with its exact value.

Check an image →
AI source type declared: where this record sits inside a PNG file and what the isGenAI report says about it. The picture is a code-drawn illustration.

What the specification says

C2PA’s hard binding is the hash of the content inside the signed claim, which breaks when the content changes. The soft-binding assertion records a watermark identifier or a fingerprint computed by a named algorithm, so a verifier that finds the same watermark or a close fingerprint in a stripped file can look up the manifest in a repository. The C2PA FAQ notes that manifests can be separated from files and that soft bindings help recover them.

How isGenAI uses soft bindings

isGenAI keeps soft-binding records that pair a manifest or claim with a SHA-256 and an isgenai-dhash-v1 fingerprint. When a checked file matches by exact hash, exact fingerprint or near fingerprint, the report lists the binding with its claim, issuer and confidence and names the relationship, so an exact match is never confused with a near one. Watermark-based soft bindings are the vendor’s domain; isGenAI implements the fingerprint side.

Limits

A soft binding is only as good as the repository it points to and the fingerprint’s resistance to crops. It recovers a claim; it does not restore the file’s own signature.

Repositories that hold manifests for soft-binding lookup are an emerging part of the ecosystem. Until they are widely used, the most dependable soft binding for most checkers is a fingerprint match against a copy someone has already checked and recorded.

How to use this term when checking a file

  1. Upload the original file to the AI image detector or the tool named on the page.
  2. Find the finding that uses this term under “How we checked” and read the source field it names.
  3. Weigh it by kind: a signed record, a declared field, a saved prompt and a matching copy are different strengths of evidence.
  4. Remember that absence of a record is not evidence of a human author.

See the term in a real report

Frequently asked questions

What is the difference between hard and soft binding?

Hard binding hashes the content inside the signed claim; soft binding uses a watermark or fingerprint to find the manifest when the file has been changed or stripped.

Does isGenAI use soft bindings?

Yes. It matches checked files to soft-binding records by hash and perceptual fingerprint and reports the relationship.

Can a soft binding prove AI origin?

It links the file to a claim whose evidence the report then shows; the strength is that of the linked record.

Is SynthID a soft binding?

An invisible watermark can serve as one when its identifier is recorded in a soft-binding assertion; isGenAI does not read watermarks.

Sources

Definitions follow the published standards linked above; the isGenAI behaviour described is the deployed checker as of October 2026.