Compare this picture with the video in your meeting. Witness checks this picture, not your meeting app’s video.
Is this video coming from a real camera?
Technical detail
What was checked ?
Proved by the camera
About the computer
- ✕
About the person
This experimental result can be wrong. It compares appearance only, so a photo or a screen held up to the camera can match. Its error rate in real calls has not been established. Do not rely on it alone to verify someone’s identity.
Covers the camera and the face in the ring, nothing more. The voice, and whatever is held before the lens, are yours to judge.
Outside the proof
The proof covers the camera and the face in the ring at the top of this page. That face was in front of a camera enrolled to this person, and what the ring shows is what the camera extension cut from those frames and sealed into the proof. Video swapped into the meeting by software, from a file or a face-swapping tool, never touches it, because the proof reads the camera and not the meeting app.
The proof does not prove a live person is in front of the lens. A deepfake can still reach this page three ways. A screen or a mask held in front of the enrolled camera is captured like anything else, and the passport face check, where it runs, judges on appearance alone. A computer with its protections switched off can be fed frames ahead of the camera extension, and if they carry the enrolled sensor’s pattern the camera check passes. On a Mac, Apple lets the app’s signing key work only while System Integrity Protection and full security mode are on, so such a Mac cannot sign its checks. The page then does not say that Apple confirmed the Mac’s security settings, and the passport face result is withdrawn. Hardware spliced into the camera module inside the computer is beyond anything software can attest.
The voice is not checked at all. The face in the ring is the face, not the speaker. Only the person using Witness is checked, and nothing here speaks for anyone else on the call. Whether the face on your call is the face in the ring, and who is talking, are yours to judge.
The sender’s Witness app may compare pictures from this call with a reference from their passport photo. This page cannot re-run that comparison or prove the photo’s origin. It withholds a match or mismatch result until the signed Mac App Attest and independent face-accuracy release checks pass, and this call has an accepted app assertion. The separate camera checks do not establish who is in front of the camera.
Checks are paused, not failing. The sender’s app has no agreed round from the public randomness beacon (drand) that timestamps each check, either because its operators are unreachable or because they briefly disagree, so no new checks are being made. The camera has not failed anything; verification resumes with the next agreed round.
This badge may not describe what you are watching. The sender’s call appears to be using a different camera from the one Witness checks, so everything above is true about a camera that may not be the one producing their video. Ask them to switch their meeting app to the Witness camera.
Waiting for evidence.
How this link reaches the camera
Each link in this chain is one thing checked, from the page you are on to the public log. Green was checked in your browser; amber is the sender’s word, which no signature covers.
What your browser checked
Re-done here, against keys built into this page.
One file holding exactly what this browser verified about this call, with the keys it verified against. Anyone can re-check it later, without this page.
How steady the signal is
How often checks and proofs arrive, and how much each covered. Steady lines are good; a gap is a wait, not a failure.
When each piece arrived
Each window on a timeline, the signed checks standing above them.
Each window this call reported
One square for each window of video, a run of consecutive frames. Solid green is proven by a receipt; light green is chained in your browser and still waiting for its receipt; an outline arrived ahead of the signed check that covers it. Hover to magnify one, click to see its evidence.