Signal launches privacy defence against Microsoft’s recall with screenshot shield

Signal has introduced a new security feature called Screen Security to its desktop application on Windows. This prevents Microsoft Recall from taking screenshots of private conversations in the chat app.

Microsoft Recall is a controversial feature that was introduced in 2024. The tool takes snapshots or screenshots every few seconds that are analyzed by artificial intelligence (AI).

Based on the results, the AI ​​can make personalized recommendations. For example, it can help you find specific documents and other information whenever you need them. The goal is to act as a sort of photographic memory for everything a user does on their computer.

Recall has been available to Copilot+ users running Windows 11 outside the EU since May last year.

Recall was highly criticized for its privacy invasion. “It’s an act of self-harm at Microsoft in the name of AI, and by proxy real customer harm,” security expert Kevin Beaumont wrote in a blog post about Microsoft’s new tool.

Recall was subsequently postponed and adjusted several times - for example, by making it opt-in. The Redmond-based tech company is planning to roll out its tool to Europe later this year, but nobody knows when that will happen.

Signal isn’t too thrilled about this, but is prepared for whenever it’s available in the EU.

“Although Microsoft made several adjustments over the past twelve months in response to critical feedback, the revamped version of Recall still places any content that’s displayed within privacy-preserving apps like Signal at risk.

“As a result, we are enabling an extra layer of protection by default on Windows 11 in order to help maintain the security of Signal Desktop on that platform even though it introduces some usability trade-offs. Microsoft has simply given us no other option,” Signal writes in a blog post.

To make sure that the privacy of Signal users isn’t in danger, developers have introduced a new security feature called Screen Security. This feature, which is enabled by default, ensures that nothing happens when someone tries to make a screenshot of a conversation when using the Signal desktop app.

The correct Digital Rights Management (DRM) flag on the Signal application ensures content won’t appear in Recall or any other screenshot application.

“Apps like Signal have essentially no control over what content Recall is able to capture, and implementing ‘DRM’ that works for you (not against you) is the best choice that we had. It’s like a scene in a movie where the villain has switched sides, and you can’t screenshot this one by default either,” Signal says.

There are a few downsides, however. For starters, Screen Security only works locally. When you’re having a conversation with someone who doesn’t have Screen Security enabled or uses a screen reader on a different operating system, keeping ‘Screen Security’ enabled on your side won’t prevent them from taking screenshots or adversely affect any accessibility software they may be using.

Secondly, Screen Security may cause problems for accessibility software such as screen readers and magnification tools for people with visual impairments. Therefore, Signal has made it possible to disable the feature in the settings menu. When Screen Security is deactivated, Signal displays a warning to indicate that Microsoft Recall can now take screenshots of the program.