Hey there! Here's a Digital Witness that has been shared with you:

Digital Witness

Issued to: WitnusApp user

In witness of the fact that data with the following digital fingerprint existed at the point in time below

Digital Data Fingerprint (Content ID)

fb01 8ec2 4fc5 b2b9 6bed ae7a 8a06 9103 d34a 7f58 c8f8 34b3 6837 10d4 999b 1d22 c142 1a41 bb17 5e09 703f 3261 6dca fbba f5f7 fe3a feee f765 296d c970 3aa3 7852

Witness Fingerprint (Witness Id)

8ebe f8e8 76f8 6541 10aa 5b0c a209 4c0d fe08 f699 3c50 b7b2 eaf2 4fb9 a2ee 81cf 355e ceae 1103 d3be 1a10 1274 f49e deab 2983 19ee 142c f3e0 e029 6582 5fe9 213a



A Digital Witness proves that something existed at a particular point in time. "Something" can be anything digital, in this case it's this photo taken by a user of the Witnus mobile app:
Evidence image
Here's a short description of the witness, from the person who shared it:
Ägarbeslut om återinvesteringar 2020 daterat 2020-01-01
This photo was taken on 8/24/2020 10:03:01 AM (Coordinated Universal Time, UTC)
It was taken here:
If you want to convince yourself that the Digital Witness is legitimate you can validate it yourself, using tools that are freely available on the Internet. Do you want to view the instructions on how to do that?
The app calculates a "fingerprint" of the photo file, and locks this fingerprint in a secure blockchain database to make sure it can't be manipulated. We call this fingerprint the Content Id, because it identifies the content.
A fingerprint is really a very large number, often presented as a long string of letters and numbers. In this case, that string looks like this:
That's pretty unreadable, so we've created an image matrix that represents that string in the form of an image instead. To compare two images, all you need to do is to drag one of them on top of the other. If they are identical, they will match up perfectly. If not, you'll notice because it looks like they are not properly aligned. Give it a try, just push one towards the other!
If the registered fingerprint matches the calculated, as it does here, it means that the content of the photo has not been modified since the time and date the photo was registered. Now let's validate that timestamp!
To do that, we again calculate a fingerprint. This time the fingerprint is based on a string that combines the first fingerprint, a signature that tells us who registered it, and the date and time this happened. Also, at the end of the string we tag on the Id of the user who created it, and the latitude and longitude where the witness was created. The combined string looks like this:
fb018ec24fc5b2b96bedae7a8a069103d34a7f58c8f834b3683710d4999b1d22c1421a41bb175e09703f32616dcafbbaf5f7fe3afeeef765296dc9703aa37852#2020-08-24T10:03:03.3665294ZWitnusApp userUserId9ccdfb85-52ee-4215-9105-b898eb197883Latitude57.7385887Longitude11.9530924
We call the calculated fingerprint of this string the Witness Id, becuase it identifies the Digital Witness. For this particular witness, the Witness Id looks like this:
Again, comparing images is easier (and more fun) than comparing strings of letters, so here you go:
If you want to validate the fingerprints yourself, you can do so by using any service that calculates SHA512 hashes. That's the technical name for the fingerprints, and if you just search for "sha512 online" on the Internet you'll find a number of such tools that are free to use.
To calculate the Content Id fingerprint, you download the media above and upload it to the hashing service and let it do its thing. The result you're looking for is matching fingerprints, that's what tells you that the media file is exactly the one that was registered.
Validating the Witness Id is even easier, you just copy the combined witness string (the one that contains the Content Id, the Signature and the Timestamp, among other things) and paste it into your SHA512 calculator service. It should then print a string that is identical to the Witness Id above. If it does, you know that the timestamp in the witness is identical to the one you just copied and pasted.
The final step is to validate that the Witness Id also has been inserted into a blockchain database, so that you can validate the timestamp of the blockchain transaction. That process is described for this particular Digital Witness on the following page (fair warning, there's quite a bit of math on the page):