drm removal from dcf. extension files

(http://stream-recorder.com/forum/showthread.php?t=412)

drm removal from dcf. extension files

In my search for info/help on drm removal i came upon this forum and i hope someone here can answer my questions. I have a Sony Ericsson mobile phone with several drm protected files programmed on it. They have a dcf. extension, which i by now understand to be the drm content format extension. I tried to remove the drm protection with sound taxi 1.0 but that program doesn?t recognize the dcf extension. I have no intention to illegally distribute the files or anything, i just like to save them on my computer for safekeeping. They are not just audiofiles btw, i also have a video and two images. Does anyone know how i can remove the drm protection so i can transport the files to my computer and possibly convert them so i can watch/listen with wmplayer?
Thank you

Re: drm removal from dcf. extension files

Hi,

I am also having a problem with dcf files. I've tried using Tunebite (amongst other DRM removal programs) but, again, the software doesn't recognise the .dcf extension. The video I am trying to decrypt is an mp4.

I've found a sample of some C# code that should the file and enable you to extract the content, but i have no clue about executing C# code!! :confused:
If anyone want's to have a go (please!), here is the C# code: http://www.example-code.com/csharp/oma-drm-read-dcf.asp

Has anyone found a way to decrypt this type of file?!?

Thanks :cool:

Compiling C# application that removes DRM from .dcf files

First of all you need a CSharp compiler (csc).

If you save the following file

Code:

// A Chilkat Crypt unlock code will work here.

Chilkat.OmaDrm omaDrm = new Chilkat.OmaDrm();

omaDrm.UnlockComponent("Anything for 30-day trial");



Chilkat.Crypt2 crypt = new Chilkat.Crypt2();



// Load an OMA DRM file.

omaDrm.LoadDcfFile("orval2.dcf");



string msg = omaDrm.ContentType + "\r\n" + 

    omaDrm.ContentUri + "\r\n" +

    omaDrm.Headers;



MessageBox.Show(msg);



// Get a specific header

MessageBox.Show("Content-Description = " + omaDrm.GetHeaderField("content-description"));



// Get the AES initialization vector

// Display the IV in hex format.

MessageBox.Show("IV: " + crypt.Encode(omaDrm.IV, "hex"));



// Display 1st 20 bytes of encrypted data in hex format

MessageBox.Show("Encrypted Data: " + crypt.Encode(omaDrm.EncryptedData, "hex").Substring(0,20));



// To decrypt, set the Base64 key and decrypt...

omaDrm.Base64Key = "BiVVJOQee6y4PWYL+fbvJA==";



// Display 1st 20 bytes of the decrypted data in hex format

MessageBox.Show("Decrypted Data: " + crypt.Encode(omaDrm.DecryptedData,"hex").Substring(0,20));



// Save the decrypted data to a file.

bool success = omaDrm.SaveDecrypted("out.gif");

if (!success)

    {

    MessageBox.Show(omaDrm.LastErrorText);

    }

as a dcfundrm.cs you may compile it using C# compiler (csc) from a command line:

Code:

csc dcfundrm.cs /r:ChilkatDotNet.dll

But you should place dcfundrm.cs and ChilkatDotNet.dll from http://www.chilkatsoft.com/downloads.asp to the same directory (if I'm not mistaken).

You may also use /out switch to change .exe name:

Code:

csc /out:dcf_undrm.exe dcfundrm.cs /r:ChilkatDotNet.dll

Note that the code provided is just an example. It can open only file with a fixed filename orval2.dcf (you can change it in the code an recompile) and decrypt it to the file with the fixed filename out.gif.

p.s. Haven't done any C# coding for about 2 years. And I have never used command prompt to compile C# applications. So sorry for the possible mistakes.

Can this C# application really remove DRM from .dcf files???

And I'm not sure with what kind of files the given C# code works. It could be EXIF/DCF (Design rule for Camera File system) files used in digital cameras or whatever.

Re: drm removal from dcf. extension files

SR, thanks a lot for the pointers. I managed (after a long struggle) to get to the stage of compiling the code, however I keep getting this error:

Error CS0116: A namespace does not directly contain members such as fields or methods

Any idea what I can do to get past this?

Many thanks :)

Re: drm removal from dcf. extension files

Please try to add the following in the beginning of the code

Code:

using Chilkat;

p.s. Gush, I don't remeber C# at all.

Re: drm removal from dcf. extension files

I cannot compile the code. Any idea what is wrong? I get the same error as the dude above, about the Chilkat part of the code (Error CS0116: A namespace does not directly contain members such as fields or methods).

Re: drm removal from dcf. extension files

And what happen then?

I'm looking for remove this dcf protection because I flashed my cell phone and it erased all my exclusive/branded content, but I made a backup first and now it's useless because I don't know how to activate this files.

I see this topic but it seems nobody continued it.

So, what was the results?

Re: drm removal from dcf. extension files

Is this thread dead now?
I have actually purchased a lot of audio DCF from the MELON website but the thing is I can't upload them onto my iPod.

I would really like to know how this thread turns out. I would love to be able to play my DRM content on my iPod.

I have been searching the web for possible solutions and this C# code seems to be the closest I could find. I don't know anything about programming though.

Has there been any further developments in this thread?

Admin: Due to the great amount of spam posts in the forum all the post are validated. So it take some time for your messages to appear.

Re: drm removal from dcf. extension files

The thread is not dead. However I haven't seen any application that can remove DRM from .dcf files.

The C# code could help to a software developer.

Also I don't really know whether the C# code is useful for OMA DRM version 2 .dcf files or only for the files of the first version.