Signal Introduces Screen Security Feature in Windows 11 Desktop App to Protect User Privacy

Signal has released an updated desktop application for Windows 11 that includes a feature called Screen Security to prevent Microsoft's Recall from capturing screenshots of secure chats. Enabled by default, this new version utilizes Digital Rights Management (DRM) to block screenshot attempts, addressing privacy concerns related to Recall's continuous screen capture functionality. The move highlights a growing tension between application developers and operating system vendors regarding access to sensitive user data.

The new version of Signal for Windows 11 incorporates Screen Security, preventing the Recall feature in Copilot+ PCs from capturing screenshots of Signal chats. Joshua Lund, a developer at Signal, explained in a blog post on May 21 that this setting is automatically enabled.

“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,” Lund said.
Lund further stated that this additional layer of protection was implemented to maintain the security of Signal Desktop on Windows 11, despite potential usability trade-offs. He added that Microsoft provided no alternative.

Microsoft’s Recall feature, which was launched last month after two delays, functions as an AI-driven tool that takes screenshots of the computer screen every few seconds. These screenshots are then stored in a searchable database. Recall is designed to serve as a "photographic memory," allowing users to revisit content viewed on their screen, such as emails or websites, based on descriptions or conversation topics.

Following its initial announcement in May of the previous year, Microsoft faced significant backlash over privacy and security concerns, leading to a rollback of the feature. The updated version of Recall is now an opt-in setting that includes an encrypted database and a sensitive data filter.

However, these changes have not alleviated Signal's concerns. The messaging platform's action underscores a widening gap between developers and operating system vendors like Microsoft concerning OS-level AI systems accessing sensitive information within applications.

Screen Security in Signal for Windows 11 employs Digital Rights Management (DRM), a technology also used to prevent screenshots of content on platforms like Netflix.

Signal acknowledges that its method of blocking Recall snapshots may not violate any rules. The platform refers to Microsoft’s official developer documentation, which states that using DRM on an app window will prevent content from appearing in Recall or other screenshot applications.

Signal recognizes that there are legitimate reasons for taking screenshots.
“For example, some accessibility software (such as screen readers or magnification tools for people who are visually impaired) may not function correctly otherwise,” it said.
Users can disable the Screen Security feature by navigating to Signal Settings > Privacy > Screen Security. Disabling Screen Security in Signal Desktop on Windows 11 will trigger a warning and require confirmation.
Signal clarified that Screen Security on a user's local computer will not prevent other users in the chat from taking screenshots of the messages.

“If you are communicating with someone who uses a screen reader on macOS or Linux, for example, keeping screen security enabled on your side won’t prevent them from taking screenshots or adversely affect any accessibility software they may be using,” Signal said.

Earlier in the year, Signal was involved in a controversy when a journalist from The Atlantic gained access to classified US government missile strike plans after being inadvertently added to a Signal group chat.