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> nothing does better than a simple black box

You still need to be aware of the context that you're censoring in. Just adding black boxes over text in a PDF will hide the text on the screen, but might still allow the text to be extracted from the file.

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Indeed. And famously, using black boxes as a background on individual words in a non-monospaced font is also susceptible to a dictionary attack on an image of the widths of the black boxes.

And even taking sharpie and drawing a black box doesn't mean the words can be seen at a certain angle or by removing the sharpie ink but not the printed ink.

Really, if you need to censor something create a duplicate without the originals. Preferably literally without the originals as the size of the black box is also an information leak.

No need for the monospaced requirement - it would reduce the search space, but it's solvable even before this reduction.

The additional leakage provided by non-monospace is rather large. With monospace all you know is the character count.

Curious anyone know if the specific censoring tool in the MacOS viewer has this problem? I had assumed not because they warn you when using the draw shapes tool that text below it can be recovered later and they don't warn you about that when using the censoring tool.

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