Create a web-based mobile app for Android.

I want to build a web and App just like the learning App, 'Visual Physics', which can be searched in Play Store. My desired App will be varied a little in design.
      I want my Video/Audio/Image file to be opened (only in that App) by its built-in player or viewer.

To Prepare a unique algorithm to Encrypt Video/Audio/Image file so that it cannot be opened in any video/audio editing software.
        And I would like to provide my users the function to create pdf file(question).
      *** The point is to prevent copying and sharing my data.*

**
      # One device = one account
          (not allow device change)
      # the files downloaded by one               
          user must not be valid to other                 
          users, if those files are shared.
          (i.E, each device/account can       
            open or play self-downloaded     
            files.)
      # App ativation or validity must   
          expired by time.
      # And I want to get the source code of this project.
        If anybody can do this, he/she can let me know with reasonable price quote.