How to hide sensitive information in a screenshot (the safe way)

A blurred card number looks safe. It often is not. Here is how to hide information in a screenshot or photo so it is actually gone.

Updated October 9, 2026 · 4 min read

Before sharing a screenshot of a bank transfer, an order or a conversation, most people cover the sensitive parts. The method chosen matters much more than it seems: some ways of hiding information only look effective, and the data can be recovered by anyone who knows how.

Why pixelating and blurring text is not safe

Pixelation replaces each block of pixels with its average color. That destroys detail, but not entirely: the average still depends on the letters underneath. Tools such as Depix (2020) and Unredacter (2022) showed that pixelated text can be reconstructed. They generate candidate texts in the same font and size, pixelate each candidate the same way, and keep the one whose result matches. The surrounding, uncensored text even reveals the font to use.

Blur works the same way in principle. It mixes neighbouring pixels, and with known fonts and a limited set of characters — digits in a card number, for instance — the original can often be guessed. The fewer possible characters, the easier it is.

What does work: a solid box

A fully opaque rectangle replaces the pixels with a single color. There is nothing left underneath to analyse. For anything that must stay secret — document numbers, card numbers, account details, license plates, addresses, codes — use a solid box, and make it a little larger than the text so the length of the hidden value is not obvious.

Blur and pixelation still have a place: faces in the background of a photo, a screen behind someone, or anything where you want to reduce detail rather than make it unrecoverable.

The mistakes that leak data anyway

Covering in an editor that keeps layers. If the box is a separate layer or annotation, whoever receives the file may be able to remove it. Export a flat image.
Cropping that does not really crop. In 2023 a flaw nicknamed “aCropalypse” showed that screenshots cropped with Google Pixel’s editor and the Windows Snipping Tool could retain the cut-out parts inside the file. Both were fixed, but the lesson stands: re-export the image rather than trusting an in-place edit.
Forgetting other copies of the same data — the same number in a notification banner, a browser tab title, or a reflection.
Hiding the value but not the context. The last four digits plus the bank name plus the date can be enough to identify a transaction.

The data you cannot see: metadata

Photos taken with a phone carry EXIF metadata: camera model, date and time, and often the exact GPS coordinates where the photo was taken. A picture of something for sale can reveal your home address. Re-exporting an image through a canvas-based editor writes only the pixels and drops this metadata; many messaging apps also strip it, but not all, and not when sending a photo “as a file”.

PDFs need special care

Drawing a black rectangle over text in a PDF usually hides nothing. The text is still there underneath, and can be selected, copied or extracted. Real PDF redaction deletes the text itself. If you are not sure your tool does that, convert the pages to images, cover the information on the images, and build a new PDF from them.

A safe routine

Take the screenshot or photo.
Cover every sensitive value with a solid box, slightly larger than the text.
Use blur only for faces and background detail.
Export a new image — this also removes location metadata.
Open the exported file and check it at full size before sending.

Cover sensitive data in an image

Try it now

Frequently asked questions

Is blurring a face enough to protect someone’s identity?

For casual sharing, a strong blur on a face in the background is usually enough. For anyone at real risk, cover the face with a solid box and check that clothing, tattoos or surroundings do not identify them anyway.

Do messaging apps remove location data from photos?

Many strip metadata from photos sent normally, but behaviour varies, and photos sent as documents or files usually keep it. Removing metadata yourself before sending is the safe default.

What color should the redaction box be?

Any fully opaque color works. Black or a neutral grey makes it obvious that something was removed, which is usually what you want.

Can I redact a PDF by converting it to images?

Yes. Convert the pages to images, cover the information with solid boxes, and turn the images back into a PDF. The text in the result can no longer be selected, which is exactly the point.