Hacker News Reader

I 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/...

View on HN

And Microsoft, literally call it the DRM flag. DRM doesn't insist on being encrypted.

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.

Thanks 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.

Reply on news.ycombinator.com