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

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!!
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

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

If you save the following file

// 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:

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:

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.

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.

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

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

using Chilkat;

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

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).

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?

[limeister]

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.

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.