In the system metrics that you can retrieve with GetSystemMetrics, one of the available options is SM_SECURE.
The only explanation provided is “Nonzero if security is present; otherwise, 0.” What does that mean? On my computer, the value is 0. There are a few different ways security can be “present” in my mind–what specifically are they talking about here?
Google, MSN, MSDN yield no useful information.