Android Question Mp3 File encryption

[DaniDPX]

Hello team B4X, I was looking for your kind support on recommending best option to encrypt .mp3 file and decrypt it before playing on a b4a app. I wanted to secure the file and decrypt it quickly as possible before playing it considering users will keep pressing next or prev button.

What I used to fetch the mp3 from http as such...

Dim o As OutputStream
o = File.OpenOutput(File.DirInternal & "/xxxx/", CurrentxxxxxID, False)
File.Copy2(Job.GetInputStream, o)
o.Close

This is how the player I use load the .mp3 file

MediaPlayer1.Load(Dir, Filename)

Thanks!
Daniel G.

 

[Brandsum]

You can use RandomAccessFile for encryption purpose and AudioStreamer for playing decrypted bytes from mp3 file.

Here is the code:

Dim data() As Byte
Dim raf As RandomAccessFile
If Not(File.Exists(File.DirDefaultExternal,"filename")) Then
    raf.Initialize(File.DirDefaultExternal,"filename",False)
    data = Bit.InputStreamToBytes(job.GetInputStream)
    raf.writeEncryptedObject(data,"encryption_key",0)
    raf.Close
Else
    raf.Initialize(File.DirDefaultExternal,"filename",False)
    data = raf.ReadEncryptedObject("encryption_key",0)
    raf.Close
End If

Dim m As AudioStreamer
m.Initialize("mediaPlayer", 44100, False, 16, m.VOLUME_MUSIC)
m.StartPlaying
m.Write(data)

 

[DaniDPX]

Thanks @Brandsum, I've followed your code snippet and made sample project. I attached it here for you to check for error I encounter. Will this code be efficient to decrypt ~ 10mb file quickly?

Sub Process_Globals

End Sub

Sub Globals
    Dim data() As Byte
    Dim raf As RandomAccessFile
    Private Label1 As Label
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Home")   
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub dd_Progress(Progress As Long, Total As Long)
    Try
'        ProgressBar1.Progress = Progress / Total * 100
        Label1.Text = NumberFormat(Progress / 1048576, 1, 2) & "MB / " & NumberFormat(Total / 1048576, 1, 2) & "MB"
        Log(Label1.Text)
    Catch
'        Log(LastException)
    End Try
End Sub

Sub dd_Complete(Job As HttpJob)
    If Not(File.Exists(File.DirDefaultExternal,"filename")) Then
'        File.WriteString(File.DirDefaultExternal,"filename","")
'        File.clo
    Log ("encrypting downloaded song")
        raf.Initialize(File.DirDefaultExternal,"filename",False)
        data = Bit.InputStreamToBytes(Job.GetInputStream)
        raf.writeEncryptedObject(data,"encryption_key",0)
        raf.Close
    End If
   
    Log("Job completed: " & Job.Success)
    Job.Release
End Sub

Sub Download_Click
    Dim dd As DownloadData
    dd.url = "http://www.hochmuth.com/mp3/Vivaldi_Sonata_eminor_.mp3"
    dd.EventName = "dd"
    dd.Target = Me
    CallSubDelayed2(DownloadService, "StartDownload", dd)
End Sub

Sub Play_Click
    If File.Exists(File.DirDefaultExternal,"filename") Then
        Log ("De-crypting downloaded song")
       
        raf.Initialize(File.DirDefaultExternal,"filename",False)
        data = raf.ReadEncryptedObject("encryption_key",0)
        raf.Close
       
        Dim m As AudioStreamer
        m.Initialize("mediaPlayer", 44100, False, 16, m.VOLUME_MUSIC)
        m.StartPlaying
        m.Write(data)
    End If
End Sub

 

[DonManfred]

Will this code be efficient to decrypt ~ 10mb file quickly?

You need to test it. Measure it then you´ll know. ;-)

 

[DaniDPX]

You need to test it. Measure it then you´ll know. ;-)

Hey @DonManfred, I've tested it before I share it here I'm looking here for any advice that can speed it up.

 

[DonManfred]

I've tested it before I share it here

Why are you asking if the speed is good when you already know it isn´t?

 

[DaniDPX]

Why are you asking if the speed is good when you already know it isn´t?

I thought you guys are better than my test report here and am kindly asking for someone helping to optimize it @DonManfred.

 

[DonManfred]

Yes, it is ok for sure. BUT you really should give us all available infos! In this case you should have noted THAT you did tried it and it is too slow.
It is an important info which you should provide when asking for help.

 

[DaniDPX]

Yes, it is ok for sure. BUT you really should give us all available infos! In this case you should have noted THAT you did tried it and it is too slow.
It is an important info which you should provide when asking for help.

Understood @DonManfred

 

[Brandsum]

I attached it here for you to check for error I encounter.

Post the error log or give detailed info about the error.