Encrypt large files on flutter and access them only through in-app - android

I am developing a digital media app using Google's flutter framework which contains songs, movies and etc. The main focus is, these media content should be accessible only through the app and not by outside methods (eg: media players, file browsers).
Eg: A music file which was downloaded through the app should only be played within the app and not by any media player. In that case, there should be an encryption method which should be used to lock these files from outside world.
In this case, bigger files such as Movies should also be taken into consideration. The size of a file can be anywhere between few kbs to 2-3 GBs.
What should be the better approach when solving this problem?
Is it to
Store everything in a database after encrypting the bytes?
Encrypt the entire file and still keep them in the form of "file"?
The downloaded data should also be able to be consumed quickly once the user requested for it. And once the consume is done, the file should be locked again from the rest of the world.
I am not sure if this topic is too broad but somehow I would appreciate it if anyone could provide me with something to start off.
Thank you.

Related

iOS & Android: Is it possible to save videos directly to the app's bundle?

My understanding is that some assets within apps (like the the splash screen) can be shown right from the start / when the user opens the app for the first time because they are bundled together with the app build. Is that also the case with videos? We need some videos within the onboarding tour to be available right away, also when in offline mode.
The simple answer is yes, you can store videos this way. You put your video in a folder named 'raw' user the resources folder.
See here for some examples: Where to put the Video file in android Project
However, video are very large so you may exceed you target app size.
You also will have to update your app if you want to update the video.
Streaming the video would avoid these issues, but you do have to have connectivity.
One compromised might be to have a small simple looked video for quick start up an offline, and switch to a streamed video as soon as it is available after startup.

Can MIT App Inventor receive image?

I am still new to cloud and mit app inventor.But I would to ask some question regarding cloud and mit app inventor.
But firsty i would like to explain how project should work.
My project is about home security system. When a press button is pressed, it will capture the image of visitor and the home owner will receive picture of the visitor on android app. The android should be able to receive picture and unlock door by pressing button unlock. The camera used is VC0706 Camera connected to Arduino Mega.
My question is that can mit app inventor receive picture from cloud since all of the picture taken will be stored in cloud.
Accessing images and sounds in App Inventor 2
Applications built with App Inventor can access sound, image, and video sources from three different kinds of locations:
Application assets
The sources labeled Media shown in the designer — part of the application's assets — are packaged with the application. Anyone who installs your application will have them, as part of the application. You also specify them in the designer, which is convenient. You can also specify these in programs by their file name: just use the file name without any special prefix. For example, if you have an image asset named kitty.png, you can use it as an image: just set the Picture property of an image component to the text kitty.png. You can similarly use files names for sound (Sound or Player) or video (VideoPlayer).
Assets are the most convenient to use, but the space for them is limited to a few megabytes, because they must be packaged with the application. They are good for small images and short audio selections. Bit you would probably not use them for complete songs or videos.
The phone SD card
You can access files on your phone's SD (secure digital) card using file names that begin with /sdcard . You could play a song on your SDCard by setting the source of a Player component to
/sdcard/Music/Blondie/The Best of Blondie/Heart of Glass.mp3
and starting the Player (assuming of course, that the song file is on the SDCard). Make sure to specify the complete file name, including the "mp3".
The Android system also includes an alternative way to designe SDCard files as URLs. Here you prefix the file name with file:///sdcard and use "URL encoding" for special characters. For example, a space is "%20". So you could designate the same file by setting the player source to
file:///sdcard/Music/Blondie/The%20Best%20of%20Blondie/Heart%20of%20Glass.mp3
Note that you'll want to use a Player component for this, not Sound. A complete song like this is too large for Sound to handle.
Images and videos can be designated similarly.
App Inventor doesn't (yet) include any way to store files on the SD card. It also doesn't (yet) include a way to list the files on the SDCard. You'll have to use other applications or the Android phone file manager for that.
Using the SD Card provides a lot more space for media than trying to package things as assets. The drawback is that users won't automatically get them by installing your application.
URLs and the Web
You can access files on Web using URLs, starting with http:// , for example, setting the picture property of an image to
http://www.google.com/images/srpr/nav_logo14.png
and similarly for music and videos. Make sure you use the link that points to the actual file, not to players for the files, which is much more common on the Web, especially for music and videos.
Other content URLs
The Android system also uses URLs to access various places that media is stored on the phone. For example, the images in the photo gallery can be accessed with file names beginning content://media/external/images/media , as you can see by using the ImagePicker and examining the resulting image path.
App inventor 2 has built-in web storage TinywebDB which stores text strings only.
In your scenario, post the images to somewhere on the web, and then store the image URIs in TinyWebDB insdie App inventor.
Yes, using MIT App Inventor you can send and receive the picture not directly but indirectly. First, you have to convert that image to imagebase64 it means in text formate then decode this text to get the original image. It means you can store any images in clouddb or firebase. Here is the video about that
https://youtu.be/ySruxnxeJgM

How to play an encrypted video file in Android

I searched through a lot of questions on SO but I can't find the answer, that's why I ask the following question:
An Android app should be able to play an encrypted video file (stored on the SD card and retrieved from a webserver).
The file has to be stored on the SD card so that the app can play the video file without having an active internet connection.
Because the video files may not be copied, the plan is to encrypt them server side when uploading the files to a webserver.
What is the best option?
1) I have seen suggestions for running a local webserver which decrypts the file (and how to do this?)
2) or should we decrypt the file, save it as a temporary file and set this temporary file as the source for the videoplayer?
3) something completely different?
You are trying to implement a DRM scheme, and a naive one at that. Look into DRM schemes and report back if you cannot implement the impossible. All you can hope for is obfuscation, and there are plenty of ways of doing that (none of them are secure of course).
What you need is DRM. Digital Rights Management (DRM) controls the access to your digital content such as video. Firstly, you need to encrypt the video with an encryption video like AES-128. Then with the use of DRM play in exoplayer. Exoplayer has DRM support. you can check here. https://exoplayer.dev/drm.html
You will expose the user to a waiting time if you choose to decrypt a entire big video beforehand. As of the security, you can guess it's a poor idea to have the contents in clear in a file, even temporary. The local webserver is a better choice because it's a streaming method, so without file storage. There is no class for an http server in the SDK, you have to implement your own one, otherwise look for an existing library similar to LocalSingleHttpServer.

Phonegap Android App - Display Store MP3 Media

I've been following this blog to help me make a simple music player function with an Android app (http://simonmacdonald.blogspot.com/2011/05/using-media-class-in-phonegap.html).
All works well - but I would like some way to extract a list of all music media stored on the phone so the user can click a file and play it. Does anyone know if this is possible via phone gap? I'd need to access track name/artist etc and a link to the track.
Cheers
Paul
Prognosis is not good.... PhoneGap does not have an API for accessing the media library. So, you would have to fall back to the File API to locate music files, and then... you would have to read the binary data in the actual files to extract out the track/artist metadata. Ouch. Seems pretty impractical.
[EDIT]
By the way, PhoneGap is not the only game in town. Appcelerator seems to solve the same problem, and apparently has a richer API, which includes
access to media metadata

android secure data storage

i am developing one android application. it download videos from server and store it in mobile.
i want to store those video in secure manner.(deny the user from copying. or deny them from viewing the video directly from sdcard)
i found two ways to solve the problem.
1)Store the video's inside the application.
2)Encrypt the entire video
but facing some problem in implementing solution
i)first solution found suitable. but i am fearing that. if we store too much video inside the application .it would become bulkier.and fore the user to uninstall.
ii)but in second solution. i did not find any correct way to do so.
so please help me to solve the problem.
This is kind of suggestion :
To store the videos you must have created some folder on SDCARD, so you can hide the folder by putting the "." in front of the name while creating it. on top of this you can encrypt the video file using AES algorithm so it can not be viewed, if copied outside the android it will not be view able. but from your application you can decry-pt the file and view it.
Definitively, you must encrypt the media and that's quite simple. What is more difficult is to play the media, because MediaPlayer only accepts clear contents. A basic way would be to convert an encrypted file to a decrypted one, just for the time of the playing session. A better approach is to build a stream from the file, decrypt that stream and feed it to the player. The hard point is to have a local http server to serve the stream.

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