— check files sealed with the FactLockCam app
This is a large proof.
The photo or video inside is 25 MiB or more, so it does not open in the browser. This page read only the file's outer label on your device and uploaded nothing.
A large proof opens in the free FactLockFile desktop Viewer, coming for Mac, Windows and Linux once each version is tested.
What to do now
The desktop Viewer is not available to download yet. Until it is:
- Save the .flcproof file and the note named factlockcam-unlock-key.txt in the same folder.
- Keep both. Do not rename or delete the note. Without the key, the file cannot be opened.
- Check back here. The download buttons go live only when each version is tested.
Nothing is lost by waiting. The file is encrypted, and its fingerprint and signed record are locked inside it.
Each download goes live only after that version is tested.
Large proofs (25 MiB or more)
A large proof opens in the free FactLockFile desktop Viewer, coming for Mac, Windows and Linux once each version is tested.
Each download goes live only after that version is tested.
What to do now
The desktop Viewer is not available to download yet. Until it is:
- Save the .flcproof file and the note named factlockcam-unlock-key.txt in the same folder.
- Keep both. Do not rename or delete the note. Without the key, the file cannot be opened.
- Check back here. The download buttons go live only when each version is tested.
Nothing is lost by waiting. The file is encrypted, and its fingerprint and signed record are locked inside it.
Questions about opening a proof
Is my file uploaded when I open a proof here?
No. The page reads the file you choose on your device and decrypts and checks it in your browser. Media is never uploaded or stored by FactLockCam. To check the public record, the page looks up the Polygon transaction by its hash. It sends no part of your file.
Where is the unlock key?
You never make a password. The FactLockCam app makes the key. For a small proof, it is in the link after #key=. That part of the link is never sent to our server, and the page removes it from the address bar. For a large proof, the key comes as a note named factlockcam-unlock-key.txt beside the file.
Why won't my proof open in the browser?
It is probably a large proof, meaning the photo or video inside is 25 MiB or more. A large proof opens in the free FactLockFile desktop Viewer, coming for Mac, Windows and Linux once each version is tested. For now, keep the .flcproof file and the factlockcam-unlock-key.txt note together in the same folder, and don't delete either one. A lost key note can't be recovered. First check the text of the message the proof came in, because the key may also be there. If it isn't, ask the sender to run Send Proof again. That makes a new file with a new key.
What do the three results mean?
File: the media inside matches the fingerprint in the signed capture record. Signature: that record was signed by the owner's key (a software key held in the phone's secure storage) and has not changed. Public record: a fingerprint of the record is on Polygon, so the record existed no later than that block. They are separate results. A capture made offline shows the public record as pending until the phone reconnects.
Does a passing check prove what happened in the photo?
No. It shows the file matches its earlier signed record. It does not prove the scene was true, who took it, or who changed another copy, and it does not decide whether a court will accept it.
Do I need the app or an account?
Not for a small proof. It opens in this browser with no app and no account. A large proof opens in the free FactLockFile desktop Viewer, coming for Mac, Windows and Linux once each version is tested.
Is the signature made in hardware?
The phone's device key is hardware-backed: Secure Enclave on iOS, and StrongBox or TEE on Android when the phone has one. The owner signature that factlockcam.com/open checks is made with a software key held in the phone's secure storage, not in hardware. Neither key shows what the camera saw, and neither is hardware camera attestation.
Own this file? Restore it into the app from Account & Settings → Backup & Restore.
Advanced: auditors with a bare proof.json can run the independent verifier.