GUIDE · ISSUE 02

A friend forwards a photo of a flat for rent. A client sends a picture of the damage. A stranger posts an image that seems too good to be real. The question is always the same: where did this come from, and has it been changed?

A photo can answer part of that question about itself. This guide explains which parts, how much each is worth, and how to check without uploading the picture anywhere.

1. Camera facts, written when the photo was taken

Most cameras and phones write facts into the file as they save it: the camera or phone model, the date and time on its clock, the exposure, sometimes the location. These facts are commonly called EXIF data.

They are useful and they are weak. Useful, because a photo that says it came from a particular phone on a particular afternoon gives you somewhere to start. Weak, because these facts are the file's own word. Free tools can edit every one of them, and the camera's clock was only ever as right as whoever set it. Most messaging and social apps also remove much of this data, often including the location, when you share a picture, which is why a forwarded photo usually says very little.

2. Content Credentials: signed, when they are there

Content Credentials are a newer, open standard (known as C2PA) for attaching a signed history to a picture: which device or app made it, and what was done to it afterwards. Because the record is signed, an edit made after signing shows up when you check it.

A growing number of cameras, phones and editing apps can add them, and some add them when an image was made or changed with generative tools. But most photos in circulation today carry none, and a missing credential says nothing against a photo: it is simply absent, the way most letters arrive without a notary's stamp.

When credentials are present, they can tell you a great deal. When they show the picture was changed after it was signed, that is worth knowing too.

3. Time stamps and proofs: when it existed

Neither camera facts nor credentials can show, on their own, when a file existed in a way a doubter has to accept. That needs a fingerprint of the file witnessed by someone else: a time stamp from a time stamp authority, an entry in a public ledger such as Bitcoin, or a Rashnova proof. If a photo, or a proof that travels with it, carries one of these, you can know the latest date it existed, exactly as it is.

Most forwarded photos carry none, and that is the most common honest answer to when did this exist?: nothing proves it.

What none of this can tell you

• +Whether what the photo shows is true. A real camera can photograph a staged scene.
• +Who took it, unless the photo carries signed credentials that say so.
• +Whether a picture was made by a person or a machine, unless its credentials say so. No honest tool can promise to tell you that from the pixels alone.

Be careful with any tool that promises to tell real from fake with confidence. The honest answer is often this file does not say, and a good tool says exactly that.

How Rashnova Origin reads a photo

Origin is part of Rashnova, free for Windows. Drop in a photo or any other file, and it reads everything the file says about itself: camera facts, Content Credentials, time stamps, Bitcoin time stamps and Rashnova proofs. Then it answers three questions in plain words: where it came from, whether it changed, and when it existed.

It reads the file on your computer. Nothing is uploaded. Where something cannot be relied on, a date that is only the file's own word, a credential that does not check, a picture changed after it was signed, Origin says so, plainly.

And for your own photos, the ones you may one day need to stand behind, Origin offers to prove them from today with Rashnova Proof.