How to securely blur text in screenshots

Blur effect and black marker are the most commonly used tools to hide sensitive information in screenshots. Unfortunately it is not a common knowledge, that both of these techniques can be reversed with relatively easy steps. No complicated Artificial Intelligence or expensive software are required. For example, in this article Jim Fisher describes how to recover blurred information with few lines of trivial pseudo code. Similarly, you can find techniques of how to undo “blacked out” text in this stackexchange discussion.

Securely hide information

A more sophisticated method is required to mask sensitive information in screenshots to avoid issues described in the introduction with conventional tools. The secure method has to be destructive and random enough to make information recovery a very hard task. At DataMask, we have been experimenting with different techniques to mask private information in web screenshots. And we have created a new distortion filter which is both destructive and random enough to be significantly better than current gaussian blur based tools. We have named the new feature “Blur+”.

How Blur+ works

The Blur+ filter applies random distortion on a website area and adds blur effect on top for cosmetic reasons. Blur+ works great for visually scrambling text and the end result looks like an alien language. Picture content is also randomly distorted, but usually the overall composition of the image can still be understood by a human and this should be taken into consideration when using Blur+. You can see how Blur+ works in practice in screenshots below.

Blur+ applied on text content

Blur+ applied on image content

Start using Blur+ with DataMask Chrome extension

Install DataMask Chrome extension to securely hide information on websites before taking the screenshot.