I need an Android video-player app that stays completely offline yet guarantees my training clips remain locked to one authorised SD card. Core workflow • On first launch, the app asks for my defined username + password. Once they match, it treats the inserted SD card as the only trusted storage and will refuse to run if any other card is present. • Every MP4 file on that card is already AES-encrypted; during playback the app silently decrypts the stream in memory and feeds it straight to the player (ExoPlayer or a comparable native component). No temporary files, no export, no screen-record-friendly cache. • Copy, share or move operations from inside or outside the app must be blocked; at most the user can pick a title and watch it. Long-press, share sheet, USB MTP access—everything should return an error or an empty file. • Wi-Fi, mobile data, Bluetooth and any cloud handshake are never used. The app must install, authenticate, and play without ever asking for a connection. Deliverables 1. Signed APK plus full Android Studio source. 2. Small desktop or command-line tool (Java/Kotlin/Python is fine) to batch-encrypt my MP4s with the same AES key the app expects. 3. Brief README covering build steps, how to change the credentials/key and how to push new encrypted videos to the authorised card. Acceptance • App refuses to open when the wrong SD card is inserted or after three bad credential attempts. • Playback starts within two seconds on a mid-range device, with zero decrypted artefacts left on storage after exit. • Installation, login, and playback demonstrated with all radios disabled. If you have done similar DRM-style media projects or have deep ExoPlayer/AES experience, this should be a quick, focused build.