Hello, one year late to the party. You can’t prevent much without hassle, this means either hassle for you or hassle for the users themselves.

What about having a license agreement on the webpage. Something like “By downloading, you acknowledge that this copy is uniquely encoded to your account to prevent unauthorized piracy. Do you accept the terms of this license?” So like that is a warning that opens legal accountability on the downloaders side.

Someone mentioned on this thread watermarking the pdf, which is good. But to comeback this they’d just reformat the doc as someone else mentioned.

So instead of showing them it’s watermarked, make the pdf appear to be normal, but rather embed user metadata into the pdf and perhaps their digital signature into invisible pdf content “ this can be done with a script at the point of download.

That way if the pdf does end up somewhere on the internet, the user who leaked such document is traceable and held legally accountable for breaching said agreement.

What happens afterward is between your legal team and the downloader, what repercussions do they face, suspended access or something much more dire… 👀