a pluggable file - based drm api layer for applications and engines . the invention defines a pluggable file - based drm api layer such that mobile operators can choose to use any file - based drm engine in their final product . an fdrm engine can be content agnostic . in accordance with the invention , an application can become drm aware by calling the novel file - based drm apis . any fdrm engine can be plugged into the novel api layer such that applications can use the protected content . the api layer of the subject invention can be designed such that applications that are drm aware by using the file - based drm api layer can be drm engine agnostic .