How to use video checksum to prove evidence authenticity
Roman Gaufman avatar
Written by Roman Gaufman
Updated over a week ago

A checksum is a sequence of numbers and letters used to check data for errors. If you know the checksum of an original file, you can use a checksum utility to confirm your copy is identical.

To produce a checksum, you run a program that puts that file through an algorithm. Typical algorithms used for this include MD5, SHA-1, SHA-256, and SHA-512.

Using the checksum, we can check the validity of the video, find the video on the platform, and confirm other details such as the start and end times of the recording, show who downloaded the video, etc.

1. To get the checksum of the video you want to share, go to the recording page and hover over the question mark.

2. Download the video by clicking on the Download button.

3. Now you can check the integrity of the downloaded file. To do this, you need the built-in Windows command-line utility certUtil or Get-FileHash ( Win10 ). Use:

C:\> certUtil -hashfile <PATH_TO_FILE> SHA1

An example of this particular downloaded video in the first screenshot:

And here you can see identical checksums, which means that the video is valid

Example:

As you can see, this example compares two not identical text files and their checksums are different.

4. If you provide us with this checksum (or even the video file), we can confirm:

  1. That the video has not been tampered with

  2. The start and end time of the recording

  3. Who viewed and downloaded the video

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