File Checksums
It is vital that the files we share with customers are protected against modifications after upload, during the download process (a “man in the middle” attack), or after downloading.
To help achieve this, we use file checksums.
How do Checksums Work?
A checksum is a short block of text that is generated based on the contents of a particular file.
It is unique: a cryptographic “fingerprint” of a file.
If a file remains the same, any checksums generated for the file will be identical.
However, if a file changes, checksums generated after the change will be clearly different to those before the change.
Generating and comparing checksums is a fast and secure way to ensure that the copy of a file on your computer, which was downloaded from a website, is exactly identical to the original file on the website itself.
How To Generate Checksums
In the Portal
Every file that is added to the Portal has a checksum automatically generated for it on upload.
This applies to Ticket Attachments and any other files uploaded to the Portal.
On your Computer
Check with the organisation responsible for management of your PC if you don’t have an application already installed.
If you are allowed to install software on your PC, then we recommend installing OpenHashtab.
How to Compare Checksums
OpenHashTab Instructions
These instructions assume you have installed OpenHashTab on your computer.
If you are using alternative software, the steps in the latter two stages will differ.
Get the Checksum of the Portal File
Ticket Attachments
- Navigate to the file on he Attachments tab
- Click the “…” button for the file (or right-click on the file’s row)
- In the pop-up menu, select “Details“
- In the details window, click “Copy to Clipboard“
- This has copied the checksum details to your computer’s clipboard
- Open a text editor on your computer (e.g. Notepad)
- Paste the copied checksum + details
- You will see the file name, algorithm used, and the checksum itself.
DataLounge Files
- Navigate to the file in the DataLounge list
- Click the “Checksum” button
- This has copied the checksum details to your computer’s clipboard
- Open a text editor on your computer (e.g. Notepad)
- Paste the copied checksum + details
- You will see the file name, algorithm used, and the checksum itself.
Get the Checksum of the Downloaded File
- Right-click on the file to check
- Select “Hashes” (on Windows 11, you may need to select “More Options…” first)
- OpenHashTab will appear, showing checksums for the file based on different cryptographic algorithms.
Compare the Two Checksums
- In your text editor, select all of the checksum you pasted earlier (only select the checksum line, not the file name/algorithm/titles)
- Copy the checksum to your clipboard
- Go back to OpenHashTab and paste the checksum into the “Check against:” text box in OpenHashTab
- If you see “SHA-512 / [Name of file]” then it’s a match! The file downloaded is identical to the one on the Portal
- If you see “No Match” then the file appears to be different to the version on the Portal!
- NOTE: Make sure you check that the entire string was copied correctly, and that there are no spaces before or after it.
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