Author (of the article, not the demo) here. I still remember debugging this thing in Turbo Debugger in DosBox and the CDQ instruction was causing trouble because Turbo Debugger could not recognise it.
I know there are companies embed digital fingerprints in all assets on their intranet. Basically the web server serves files with different fingerprints for each employee. These fingerprints can survive even resizing/processing/re-encoding. Company then will be able to track down the person who leaked it by simply looking at the leaked file.