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Hi,
I am working on an application (WinForms) where a user wants to prevent the form to be shared using any of the application like (Skype, GoToMeeting, Lync etc), plus it should also prevent the screen to be recorded.
I have managed to work on KeyBoard hooks, where I am blocking keys like PrintScreen and Function keys. Please suggest any mechanism to achive the avove functionality.
I have gone through Google, but not able to find any thing. (I need functionality like Digify).
Thanks
Anjani
I had a very brief read about Digify, and they way they do it is to have the file only openable by the Digify client app.
I assume they have there own file format of some sort, so a file is imported into the digify format and encrypted (i am guessing a bit here as i have not used the product) and then the Client app stops print screens e.t.c.
It also uses watermarking, to guard against someone just using there camera and pointing it at the screen.
This sounds like quite a big project, i hope they are paying you enough !!!
I am trying to do the same, the WinForms application that will open some documents lying on the central server. The user will be given access to them and then same will be available for him to open. It can be any document (doc, pdf, image etc.). The app will have its own viewer for opening the documents. Watermarking is all done. Need to prevent recording and share functionality.
I don't think you can.
What you can do is prevent a form from loading or unload a form when you detect some specific application are running or started.
There's not going to be a clean solution. Screen recording isn't an OS feature, so there aren't convenient APIs to let you know when it's happening or control it. There also aren't any standards, so there isn't some third-party library you can connect with to opt out of screen sharing.
So there's only bad solutions that don't work reliably and/or are easy to defeat.
You could keep a list of known screen recording software and refuse to show data if any of those processes are running: that won't protect from screenshots, file renames, or that there's hundreds of programs you'd have to know about and more being made often.
You could consider displaying the data in a way such that it's illegible without a special physical filter installed on the monitor. This won't protect you from users with cameras, and some form of image processing might be able to defeat it anyway.
I know people who work in secure facilities and their documents are protected by layers of software, hardware, and physical measures. They are not allowed to bring phones or other electronic devices into the office. Their documents are in systems with clear audit trails, so it's always clear who accessed what data. Some machines with exceptionally sensitive data reside on machines with no internet connection in locked, windowless rooms that require the presence of lawyers and security personnel for entry.
Data still leaks after all those precautions, so it's not an easy game to play.
I read that Windows can prohibit window capturing from Vista onwards. You apparently do it by calling the SetWindowDisplayAffinity function. It depends on the DWM (Desktop Window Manager) service running, which it always is in Win8/10. In Vista/Win7 you have to check that the DWM is running with DwmIsCompositionEnabled before showing your data.
BB