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    It's easier than ever to de-censor videos

    (www.jeffgeerling.com)
    382 points DamonHD | 15 comments | 15 Apr 25 17:12 UTC | HN request time: 2.396s | source | bottom
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    AdmiralAsshat ◴[15 Apr 25 19:33 UTC] No.43697419[source]▶
    My Windows-98 approved method for redacting a screenshot:

    1) Open screenshot in MS-Paint (can you even install MS-Paint anymore? Or is it Paint3D now?)

    2) Select Color 1: Black

    3) Select Color 2: Black

    4) Use rectangular selection tool to select piece of text I want to censor.

    5) Click the DEL key. The rectangle should now be solid black.

    6) Save the screenshot.

    As far as I know, AI hasn't figured out a way to de-censor solid black yet.

    replies(18): >>43697459 #>>43697468 #>>43697505 #>>43697519 #>>43697570 #>>43697579 #>>43697609 #>>43697637 #>>43697671 #>>43697672 #>>43697686 #>>43697695 #>>43697917 #>>43697983 #>>43698183 #>>43698548 #>>43699015 #>>43702531 #
    1. its-summertime ◴[15 Apr 25 19:45 UTC] No.43697519[source]▶
    There was a programming competition, can't remember which, similar to IOCCC but more about problematic software? where the redaction was reversible despite being pure black, due to the format chosen allowing for left over information in the image (vastly reduced quality but it was enough to allow text to be recovered!) [edit: see replies!]

    There was also the Android (and iOS?) truncation issue where parts of the original image were preserved if the edited image took up less space. [edit: also see replies!]

    Knowing some formats have such flaws (and I'm too lazy to learn which), I think the best option I think is to replace step 6 with "screenshot the redacted image", so in effect its a completely new image based on what the redacted image looks like, not on any potential intricacies of the format et al.

    replies(9): >>43697673 #>>43697743 #>>43697816 #>>43697821 #>>43697825 #>>43698509 #>>43698669 #>>43698736 #>>43699375 #
    2. evertedsphere ◴[15 Apr 25 20:01 UTC] No.43697673[source]▶
    https://www.underhanded-c.org/_page_id_17.html
    3. ZeWaka ◴[15 Apr 25 20:06 UTC] No.43697743[source]▶
    There's tricks like this with embedded thumbnails.
    4. fanf2 ◴[15 Apr 25 20:12 UTC] No.43697816[source]▶
    You are thinking of John Meacham’s winning entry in the 2008 underhanded C contest https://www.underhanded-c.org/_page_id_17.html
    replies(1): >>43698598 #
    5. qwertox ◴[15 Apr 25 20:12 UTC] No.43697821[source]▶
    Maybe you're referring to "aCropalypse". Also there was an issue once where sections with overpainted solid black color still retained the information in the alpha channel.

    https://www.wired.com/story/acropalyse-google-markup-windows...

    https://www.lifewire.com/acropalypse-vulnerability-shows-why...

    replies(1): >>43698225 #
    6. googlryas ◴[15 Apr 25 20:12 UTC] No.43697825[source]▶
    The underhanded C contest: https://www.underhanded-c.org/
    replies(1): >>43699067 #
    7. Modified3019 ◴[15 Apr 25 20:51 UTC] No.43698225[source]▶
    I also recall at one point some image file format that ended up leaking sensitive info, because it had a embedded preview or compressed image, and the editing program failed to regenerate the preview after a censor attempt.

    Was a loooong time ago, so I don’t remember the details.

    replies(1): >>43698326 #
    8. fullstop ◴[15 Apr 25 21:01 UTC] No.43698326{3}[source]▶
    AT&T leaked information, as did the US Attorney's Office, when they released PDFs with redacted information. To redact, they changed the background of the text to match the color of the text. You could still copy and paste the text block to reveal the original contents.

    https://www.cnet.com/tech/tech-industry/at-38t-leaks-sensiti...

    9. ◴[15 Apr 25 21:18 UTC] No.43698509[source]▶
    10. turnsout ◴[15 Apr 25 21:27 UTC] No.43698598[source]▶
    Wow, it took me a minute to figure out how his entry works. You really could read that code and assume it was correct. The resulting image is perfectly redacted visually, and the missing data is not appended or hidden elsewhere in the file. You would only discover it by inspecting the PPM image in a text editor. Very sneaky!
    11. youainti ◴[15 Apr 25 21:33 UTC] No.43698669[source]▶
    I would guess that would be due to compression algorithms.
    12. rkagerer ◴[15 Apr 25 21:41 UTC] No.43698736[source]▶
    Step 5.5) Take a new screenshot of the image.
    replies(1): >>43699382 #
    13. teddyh ◴[15 Apr 25 22:12 UTC] No.43699067[source]▶
    Too bad that they only show the winners up to 2015. All the later ones are on github.com, but are harder to find.
    14. Calwestjobs ◴[15 Apr 25 22:51 UTC] No.43699375[source]▶
    what about intentional adding data into image?

    screenshot - im not convinced apple does not use invisible watermark to add info into image data. but for fact every photo you take with iphone, contains invisible watermark with your "phone serial number". to remove such watermarks, facebook is converting every picture you post for last 10 years... just weird extra con to using modern technology.

    try to copy banknote on your printer, it will not print anything, just says error. + every page of text printed contains barely visible yellow marks containing again serial number of printer.

    ....

    15. Calwestjobs ◴[15 Apr 25 22:53 UTC] No.43699382[source]▶
    step 5.5.5 - tell chatgpt what is on image to regenerate it for you XD