How can I create a window which is fully apparent to the user but is not visible in screenshots. I know that this is possible since Neo SafeKeys (an onscreen keyboard to defeat keyloggers) does not appear in the screenshots taken by keylogging software I installed.
To give you an idea, the window is fully visible to the user, however when a screenshot is taken, the Neo SafeKeys window does not appear at all (as if it does not even exist).
Neo SafeKeys states that it uses an invisible protection layer above the window to protect against screenshots. I have searched all over the internet to see how can I reproduce this, to no avail. Does anybody know how this can be performed (windows which is visible to user but invisible in screenshots)?
What you can do is you can prevent the PrtScn key from doing anything when pressed. Take a look at this article while shows you how to do this.
What this article is doing is clearing out the clipboard. What you can do instead is capture the screen image and digitally remove your application, then put the revised image on the clipboard, thus giving the "Effect" of making your window transparent.
Also, you might want to look at this SO question which gives an alternative way to make your window just appear "blue", though its not easy to do.