How to Properly Hide Sensitive Information in a Screenshot

Screenshots end up everywhere: bug reports, tutorials, support tickets, social posts. Most people know to hide passwords and emails before sharing one. Fewer people know that the way you hide them matters.

Why a weak blur isn’t enough

Pixelation and light blur mix nearby pixels together, but they keep a lot of the original information. For text in a known font, such as a code, an account number or an email address, researchers have shown that pixelated text can sometimes be reconstructed by trying candidate strings until the pixelated output matches. The shorter and more predictable the text, the easier this is.

Rules for redaction that holds up

1. Use a solid box for anything truly secret. A filled black or colored rectangle leaves nothing to reconstruct.
2. If you blur, blur hard. Use a strong radius so that no letter shapes are visible at all.
3. Cover the whole field, including its length. The width of a redaction can reveal how many characters are underneath.
4. Flatten the image before sharing. Export as PNG or JPG. Editable formats like PSD or layered PDFs can keep the original under the redaction.
5. Check the edges. Tooltips, autocomplete dropdowns and browser tabs often repeat the same data somewhere else in the screenshot.

Faster: blur before you capture

If the screenshot is of a web page, you can skip the editing step. Blur the sensitive elements on the live page first, then take the screenshot. With BlurSite, push the intensity slider to maximum for anything secret, and the captured image never contains the original text.