Hidden PDFs. Or so it seems!

Let’s say you have a PDF file with sensitive information (personal data, for GDPR, should generally be kept private).

I saw from time to time this solution – adding a square/rectangle with a black (or any other color) element, so that the information is to be kept private.

The problem is that there’s an easy workaround – you can simply select a text, and you can see what is hidden behind the rectangle.

Even if in PDFs you can’t see what’s behind a rectangle, you can still select it and get the data.

Quite an issue.