RioShot

Redact a Screenshot Safely: Why Blur Is Not Enough

You take a screenshot to show a bug, a result or a settings page, and only after posting it do you notice the email address in the corner. Redacting a screenshot takes a few seconds, but doing it in a way that actually hides the information takes a little care.

The short version

  1. Use a solid block for anything secret: passwords, API keys, account numbers, tokens.
  2. Use blur or pixelate only for things that just need to be out of focus, like faces or background clutter.
  3. Check the edges of the screenshot, not just the middle.
  4. Share an image that was saved fresh by the editor, not the original file.

You can do all four with the Redact a screenshot tool, which starts on the solid style.

Why blur and pixelation are not always safe

Blur and pixelation look convincing, but they do not delete information. They average it. Each blurred or pixelated block still depends on the letters that were underneath it.

For long, unpredictable text that is usually fine. For short text in a known font, it can be a problem. Someone who knows (or guesses) the font and size can render every likely candidate, blur or pixelate it the same way, and compare. Open source tools such as Depix and Unredacter have shown this working on pixelated text.

A solid block has no such weakness. The pixels underneath are replaced with a flat color, so there is nothing left to compare against.

Rule of thumb: if it would hurt to have it guessed, cover it with a solid block.

What people forget to hide

The obvious thing in the middle of the screenshot is rarely the one that leaks. Look at:

  • The address bar. URLs often contain user IDs, order numbers, search terms, or even login tokens.
  • Browser tabs and bookmarks. Tab titles reveal what else you had open.
  • Profile menus and avatars. Your name, email and photo often sit in a corner.
  • Notifications. A message preview can pop up right as you take the screenshot.
  • File paths and terminal prompts. These often include your username and machine name.
  • Timestamps and time zones. Together, these can narrow down where you are.

If a whole region is irrelevant, cropping it out is even better than covering it.

Share a freshly saved image

Two less obvious leaks come from the file itself, not from what you can see.

Hidden data in the original file. Photos and some screenshots carry metadata, such as the device, the time and sometimes the location. An editor that redraws the image from scratch drops all of that.

Leftovers from cropping. In 2023, a bug nicknamed “aCropalypse” showed that some built-in phone and desktop screenshot tools left parts of the original, uncropped image inside the saved file. A cropped or redacted file looked fine but could be partly restored.

RioShot avoids both by drawing a brand new image when you copy or download. Nothing from the original file is carried over except the pixels you see.

Redact a screenshot in three steps

  1. Open the Redact a screenshot tool and drop, paste or choose your image.
  2. Click Hide an area and drag over each private detail. Solid is already selected.
  3. Look over the whole image once more, then copy or download it.

Your image is edited entirely in your browser and is never uploaded, so the screenshot you are trying to protect does not travel anywhere in the process.