How to play encrypted video file using WindowsMediaPlayer?

Question

I encrypt my .mp4 into a custom format (.opu). Now I should decrypt my file and save them into temp folder at the start of my application. and play them using WindowsMediaPlayer control in C#. So I have the risk of stealing my files from temp folder. What is the best way to prevent stealing my files? How to play encrypted video file using WindowsMediaPlayer?

Answer 1

The best way would be to perform the decrypt to a stream in memory and play the video from there. That way there is never an on-disk file to steal.

Answer 2

There is a way using virtualization, i.e. hooks. The idea is to hook functions like ReadFile to provide decrypted data, SetFilePointer to maintain current pointer within a "file" etc. You can view one of the examples at http://www.boxedapp.com/encrypted_video_streaming.html