title_body: Create a DRM Compatible reader?
upvoted_answer: Amazon and Apple have their own DRM schemes and you won't be able to create an ereader that opens books from their stores. But most others use Adobe DRM, and you can license Adobe's Reader Mobile SDK to do this. ARMSDK is very expensive (when I was involved with a related project many years ago, it was many thousands of dollars a year for a license), and it is difficult to work with.
  
  You may find these links helpful:
  
  
  An overview of related tech on the Bluefire blog
  A decent sales page for ARMSDK