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In short: Signal uses DRM to prevent Windows Recall (spyware) from capturing what's inside the app. It's similar to how Netflix prevents piracy. That's an inte
by yupyupyups 1y ago
In short: Signal uses DRM to prevent Windows Recall (spyware) from capturing what's inside the app. It's similar to how Netflix prevents piracy.
That's an interesting use-case of web DRM.
There are other details in the article, for example about Recall forces users to use biometrics to then permit them to authenticate using a PIN code. That's an interesting observation.
- mmozeiko 1y agoI don't know why Signal calls it "DRM" because the do not use DRM for this. Typically DRM means encryption & keys are involved (which is what Netflix & others are doing with Widevine or PlayReady). All Signal does is just a simple Windows API call to exclude window from screen capture. SetWindowDisplayAffinity function with WDA_EXCLUDEFROMCAPTURE argument: https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowdisplayaffinity https://learn.microsoft.com/en-us/windows/win32/api/winuser/...
- yupyupyups 1y agoThanks for the insight, I thought they took advantage of the whole DRM stack (including HDCP in monitors) to encrypt the UI and let the monitor decrypt it.
- k_roy 1y agoAnd Microsoft, literally call it the DRM flag. DRM doesn't insist on being encrypted. https://learn.microsoft.com/en-us/windows/client-management/manage-recall https://learn.microsoft.com/en-us/windows/client-management/... And that "simple Windows API" call is pretty much absolute, since it's across the stack.