android app

1) app might contain 10 to 15 audio or video files. 2) by default we will provide 2 or 3 files for free download. 3) after purchasing the app user can able to download rest of all files. 4) files downloaded to be in encrypted format and decryption need to be done by our app on real time. 5) by the point no.4 all video and audio files will be played only with our app. 6) when user click on download link we should prompt him to select the video quality. and the same quality video need to be get downloaded using via web service. 7) when end user downloaded the app you need to call our web service and pass on the information of user ID and app he downloaded. 8) when end user purchased the app you need to call our web service and pass on the information of User ID and app he purchased. 9) when ever user clicked on download link you need to call the web service to download the file, by passing the details like (User ID, Video ID) if user purchased the app then we will be sending the video file as response. if he dose not then you will be getting the response as "0" (zero). 10) video ID's will be static and hard coded in the app. Video will be provided by the client.