Re:A tool for recovering passwords from pixelized screenshots
by dragonwriter on Sunday December 06, 2020 @08:38PM
(#25328541)
> Second, if you don't use monospace text, the width of the text you are redacting will reveal information about it.
If you do use monospace text, width reveals the exact redacted character count. If you don't use monospace text, it constrains the possible contents in a more complicated way, but it leaks information either way.
Re:A tool for recovering passwords from pixelized screenshots
by spoonjim on Monday December 07, 2020 @03:26AM
(#25330328)
It leaks much less information when monospaced, although that information is easier to retrieve. Anyone can just visually inspect and see exactly how many monospaced characters were removed, but someone with the right tools and skills can narrow down the potential characters quite a bit if it's a short piece of non monospaced text.
Re:A tool for recovering passwords from pixelized screenshots
by davchana on Sunday December 06, 2020 @05:53PM
(#25327443)
Yes, in pdf, add bars, & then print it again as pdf, but as image.
Re:A tool for recovering passwords from pixelized screenshots
by jbverschoor on Sunday December 06, 2020 @06:37PM
(#25327750)
Even black bars all leak the face that there’s something hidden
Re:A tool for recovering passwords from pixelized screenshots
by davchana on Sunday December 06, 2020 @07:21PM
(#25328007)
Do you mean the typeface/font? If it is just a word we are hiding in a sentence/paragraph; it would be like fill in a blank task for reader; much more chance to guess from context. There, the leaking length will not matter.
Re:A tool for recovering passwords from pixelized screenshots
by davchana on Monday December 07, 2020 @12:37AM
(#25329616)
Oh sorry, my bad, you mean fact, not face. Yes, I agree.
Re:A tool for recovering passwords from pixelized screenshots
by jbverschoor on Monday December 07, 2020 @03:36AM
(#25330382)
ah. yeah fact :-)
Re:A tool for recovering passwords from pixelized screenshots
by spoonjim on Monday December 07, 2020 @03:24AM
(#25330312)
This is why the real professionals use the same mechanism they always have: cut the offending text out of the paper with an x-Acto knife and make a photocopy.
Re:A tool for recovering passwords from pixelized screenshots
by Scoundreller on Monday December 07, 2020 @04:11AM
(#25330540)
Also helps prevent any issues related to double sided printing and bleedthrough.
Re:A tool for recovering passwords from pixelized screenshots
by antegamisou on Sunday December 06, 2020 @08:33PM
(#25328515)
> First, if you add black bars on your own and don't use professional redaction features of software, you might miss the OCR text layer of the PDF, or the bar might be added as a separate object entirely which means it can also be removed later on.
Looking at you, Preview on macOS.
First, if you add black bars on your own and don't use professional redaction features of software, you might miss the OCR text layer of the PDF, or the bar might be added as a separate object entirely which means it can also be removed later on.
Second, if you don't use monospace text, the width of the text you are redacting will reveal information about it. That's why monospace fonts are so commonly used in the intelligence community for example.
Third, if you just add a black bar to a screenshot, there might be residual values of the text left in adjacent seemingly white portions of the image, but they might not be entirely white due to compression effects. Better you run it through a filter before publishing.