![]() ![]() (Make the redactions more obvious.) I would not rely on the flood fill alone on the off chance that I accidentally use the wrong tool settings. ![]() Changing the color to black is just for the recipient's benefit. The fool proof method would be to use the rectangle selection box, press delete, and fill (without deselecting) the same space black.įlood filling the space in with black doesn't redact anything more than what the deletion deletion did. I suggest importing the image in GIMP, manipulating it, then export in JPEG or PNG format. However I wouldn't be shocked if the pen tool was semi-transparent in other iOS versions. That article recommends against using the pen tool, even though they say it is opaque, because it's hard to completely write over text with such small lines. If you search "ios markup redaction" you'll probably see PSA: iOS Markup is not designed to be a redaction tool for sensitive information. (Even if you use the opacity slider at its max setting.) It's not safe to use Markup's pencil or marker tools for redaction because they are not opaque. PS - The images above are examples and not the actual thing I sent! It just says "LALALALALA BATMAN!" Using whatever technique you want, is there any way possible way to see what is under the blacked out parts in the screenshot, because that was what I actually then sent to the journalist. So, let's say this was the edited original picture (it's in JPEG format because when I sent it from my iPhone via iCloud mail to my other email address then downloaded it on to my laptop from that other email address, it downloaded in JPEG, but the screenshot downloaded as a PNG): Then, I sent that image from my desktop to the journalist. Then, I took a screenshot, then sent the screenshot from my phone to my email account, then downloaded the image to my laptop. However, one of the images contained my date of birth and other personal information so I blacked it out using markup tools in the Photos app of my iPhone 6 (running iOS 10.3.2). Following trial and error, he found the font was 24px.Ok, so I sent some pictures to a journalist to report something I thought was noteworthy. ![]() He was then able to find the correct font and size of the text, which was made easier due to the file being from MS Notepad - the app uses the default font of Consolas. Petro also had to lighten part of the image to help his tool process it. His tool renders the letters to a headless Chrome window, meaning no colourised artefacts appear. To use it, he had to first convert the image to grayscale, as it appeared to contain some coloured letters. To solve the challenge, Petro enlisted a tool he developed called Unredacter, which takes redacted pixelated text and reverses it back into its original form. This algorithm is also widely standardised, so the same result is created regardless of whether GiMP, Photoshop, or most other tools are used, he added. ![]() However, while some information is lost in the process, it leaks plenty through, warned Petro. For each block, the tool will then set the redacted image's colour equal to the average colour of the original, in an attempt to "smear" the information of the image. A sample of the redacted text issued as part of the challenge (Image credit: Dan Petro)Įxplaining how pixelation usually works, Petro said that tools normally divide an image into a grid of a given block size. ![]()
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