2. Create a folder "Global Hotkey" and copy contents of downloaded DMG to that.
3. In a terminal do:
cd "/Applications/Global Hotkey"
ln -s /System/Library/Frameworks/ScreenSaver.framework/Versions/A/Resources/ScreenSaverEngine.app "command f10"
4. Make sure Screensaver is set to prompt for password (you may need to relog for this to take effect)
5. Preferences -> Accounts ->
6. Launch the app as well