How to Prove a Photo Was Not Edited

The sequence that can be checked

1. Capture the photo or video inside FactLockCam before the scene changes.
2. The app fingerprints the exact bytes, signs the capture record, and anchors a fingerprint of that record on Polygon when the phone is online. Offline captures are anchored after it reconnects.
3. Send the original as one .flcproof proof. A small proof opens in the recipient's browser at /open. A large proof opens in the free FactLockFile desktop Viewer, coming for Mac, Windows and Linux once each version is tested.
4. The verifier compares the inspected file with the earlier fingerprint, then checks the signature and, when present, the public record.

What this is not

This is not an AI detector. It does not score whether pixels “look synthetic.” It compares a specific file with an earlier signed record. Verifies the exact file and signed record—not the physical truth of the scene.

The capture time comes from the phone's clock. Polygon shows only that the signed record existed no later than a given block.

Try the live pair on Can you tell which one changed? The original matches. The demonstration altered copy returns media_hash_mismatch.