Witness support

Whatever the problem is, a person reads these and answers. There is no ticket queue to disappear into.

Getting started

What Witness does

Witness measures your camera's own sensor, and proves that the video it publishes came from that camera. The person on the other end checks that proof in their browser, and does not need to install anything. Their page also shows them a small picture of your face, cut by Witness from the very frames it checked and sealed so that nothing on the way could change it.

What your meeting app then shows them is a separate thing, carried by that app and not checked by Witness. The person checking compares the picture on their page with the face on the call. See the picture below.

Setting it up

Install the app, sign in, and follow the enrolment steps. Enrolment measures your camera's own sensor, which is what later proofs are compared against, so it takes a couple of minutes and needs decent light. You only do it once per camera.

Starting a verified call

Select Witness Camera as your camera in Zoom, Meet, Teams or any app that lets you choose a camera, and Witness starts verifying on its own. The Witness app shows nine words: read them to the person you are speaking with, and they type them at witness.apertrue.photo/verify. Their page then shows three words; ask them to read those back, and type them into the Witness app to let them in. Do not send them a link: saying the words on the call is what ties the check to it. See getting set up for every step.

What do I need?

A MacBook with Apple silicon on macOS 27 or later, an iPhone, and a passport with a chip. Witness verifies the MacBook's built-in camera, not an external webcam. Look for the chip symbol on the passport's cover. The person checking your call needs only a browser.

Which passports work?

A passport with a chip. Not every country's passport can be read yet, and the app tells you if it cannot read yours. Identity cards are not accepted today, and neither are driving licences, for the reason below.

Can I use a driving licence instead of a passport?

Not today. Witness reads the chip inside a passport, which carries a signature from the issuing government that your phone can check on its own, without sending the document anywhere. Most driving licences have no such chip. Digital licences are arriving, in the mobile driving licence format some regions have started issuing and in the European digital identity wallet, and those carry signatures of the same kind. Support for them is on our list once they are common enough to rely on. Until then, the passport is what we can verify without trusting a middleman, and that is the point of using it.

Reading the verification page

The badge

The badge is about the camera. Green means a recent check passed and the proof is current. Amber means the last check passed but is getting old. Grey means no recent check has arrived and nothing has failed. Red means a check did not pass.

The picture

Beside the badge is a small picture of the sender's face. Witness cut it from the frames it checked against the enrolled camera, sealed its fingerprint into the record the checks sign and the proofs cover, and encrypted it so that only the people you let in can open it. The page opens it and checks it against that record itself. A picture that does not match shows red, and the page says so in those words.

The video in your meeting app is not checked by Witness. Compare it with this picture. If the face on the call is not the face in the picture, the call is not what it claims to be, whatever the badge says.

When something is not working

The badge is grey and nothing is happening

The usual cause is that the meeting is not using Witness Camera, so nothing is being sent through the verified path and there is nothing to vouch for. Check the camera selected in your meeting software.

The other person says the words do not work

The words change as the call goes on, and stop working when you end the call. Read them the words the Witness app shows now, one at a time, and have them type each as you say it.

Checks paused, no agreed randomness

Witness uses a public randomness beacon that several organisations publish together. If they are unreachable or disagree, checks pause until that resolves. Your camera has not failed anything, and the page says so in those words.

I have lost my passkeys

If Google sign-in is connected to your account, sign in with it on the account page and add a new passkey. If not, choose "Lost every passkey?" under the sign-in form and enter your address. A link goes to the mailbox that made the account; open it on the device the new passkey should live on and approve the prompt. The new passkey always starts working three days later, so that someone who can read your email cannot take the account. Until then, sign in another way if you can (another passkey, Google, or your company's sign-in), and from there you can cancel it if it wasn't you. Your identity, your devices and your receipts are unchanged by recovery. Remove any old passkey you no longer hold from the account page afterwards.

Enrolment asks for more light at the plain surface

In dim light some cameras smooth their picture, and the smoothing hides the faint pattern Witness measures. The app reads the plain surface only while the camera says it is not smoothing, so it waits and asks for more light. Turn a lamp on, face a window, or move the surface into brighter light. Good light matters most at this step. Once the camera is registered, calls are checked in the light the room has, and if that light is affecting the checks, the app tells you during the call.

Enrolment will not complete

Enrolment needs steady light and a still camera. If it keeps refusing, email us with what the app said. A refusal is deliberate: an enrolment that is not good enough would produce checks that fail later for no reason.

What Witness does not claim

Witness proves that frames came from a particular enrolled camera. It does not prove that the person in front of that camera is who they say they are unless they have chosen to link a verified identity, and it cannot tell you what happens to those frames after they leave the verified path. Where we do not know something, the page says so rather than filling the gap. Three things in particular it cannot see: a screen or a mask held in front of a registered camera, a camera physically swapped for another, and a machine whose system protections were switched off. From macOS 27 the page says whether the sender's Mac attested that its protections were on; before that, it cannot tell. If any of our software ever claims more than that, tell us, and treat it as a bug.

Privacy and your data

You can export everything we hold about your account, and delete your account, from your account page. Your camera's measurements stay on your machine: what reaches us is proof, and a small sealed picture of your face that only the person you are calling can open.

See the privacy policy and terms of use.