Here's a great gift idea just in time for the holidays: Make your friends and relatives their very own copy-protected CDs using the same industrial-grade passive protection technology built into XCP and Macrovision discs.
Passive protection exploits subtle differences between the way computers read CDs and the way ordinary CD players do. By changing the layout of data on the CD, it's sometimes possible to confuse computers without affecting ordinary players — or so the theory goes. In practice, the distinction between computers and CD players is less precise. Older generations of CD copy protection, which relied entirely on passive protection, proved easy to copy in some computers and impossible to play on some CD players. For these reasons, copy protection vendors now use active protection — special software designed to block copying.
Discs with XCP or Macrovision protection employ active protection in conjunction with a milder form of passive protection. You can create your own CD with exactly the same passive protection by following a straightforward five-step procedure. I'll describe the procedure here, and then explain why it works.
What you'll need:
- A computer running a recent version of Windows (instructions are Windows-specific; perhaps someone will write instructions for MacOS or Linux)
- Nero, a popular CD burning application
- CloneCD, an advanced disc duplication utility
- Two blank recordable CDs
Step 1: Burn a regular audio CD
Start Nero Burning ROM and create a new Audio CD project. [View] Add the audio tracks that you want to include on your copy-protected disc. [View] When you're ready to record, click the Burn button on the toolbar. In the Burn tab, make sure "Finalize disc" is unchecked. [View] Insert a blank CD and click Burn. Be careful not to infringe any copyrights! For loads of great music that you can copy legally, visitCreative Commons.
Step 2: Add a data session to the CD
Start another Nero compilation, this time selecting the "CD-ROM ISO" project type. In the Multisession tab, make sure "Start Multisession disc" is selected; and in the ISO tab, make sure Data Mode is set to "Mode 2 / XA". [View] Add any files that you want to be accessible when the CD is used in a computer. You might include "bonus" content, such as album art and lyrics. [View] For a more professional effect, consider adding the installer for your favorite spyware application and creating anAutorun.inf file so it starts automatically. When you're finished, click the Burn toolbar button. Insert the audio CD you created in Step 1, and click Burn. [View] Nero should warn you that the disc you've inserted is not empty; click Yes to add your data files as a second session. [View]
At this point, you've created a CD that contains both audio tracks and data files. The data files you put on the CD should be visible in Windows Explorer (in My Computer, right click the CD icon and click Open) and the audio tracks should be rippable with your favorite audio player. To add passive copy protection, you'll need to modify the layout of the data on the disc so that the audio tracks are more difficult to access.
Step 3: Rip the CD as a CloneCD image file
Make sure the CD you just created is still in the drive and start CloneCD. Click the "Read to Image File" button. Select your drive and click Next. Choose "Multimedia Audio CD" and click Next. [View] Select an easy to find location for the image file and click OK to begin ripping.
Step 4: Modify the image file to add passive protection
The CloneCD image you created in step 3 actually consists of three files with names ending in .CCD, .IMG, and .SUB. The .CCD file describes the layout of the tracks and sessions on the CD. You'll edit this file to add the passive protection.
Start Windows Notepad and open the .CCD file. Modifying the file by hand would be tedious, so I've created an online application to help. Copy the entire contents of the file to the clipboard and paste it into this form, then click Upload. Copy the output from the web page and paste it back into Notepad, replacing the original file contents. [View] Save the file and exit Notepad.
Step 5: Burn the modified image to create a copy-protected CD
Insert a blank CD and start CloneCD again. Click the "Write From Image File" button. Select the image file you modified in step 4 and click next. Select your CD recorder and click Next. Select "Multimedia Audio CD" and click OK to begin burning. [View]
That's it! You've created your very own copy-protected CD.
Now it's time to test your disc. If everything worked, the files from the data session will be visible from My Computer, but the audio tracks will not appear in Windows Media Player, iTunes, and most other mainstream music players. The CD should play correctly in standalone CD players.
How it works. To see how this form of passive protection works, you can examine the layout of the CD you created. Start Nero and select Disc Info from the Recorder menu. You should see something like this:
(The exact number of tracks you see will depend on how many songs you included.)
Notice that the tracks are grouped into two sessions — essentially two independent CDs burned onto the same disc. Unprotected CDs that combine audio and data files contain audio tracks in the first session and a single data track in the second. The only difference in the passive protected CD you just created is that the second session contains two tracks instead of one.
You added the extra track (shown in yellow) when you edited the disc image in step 4. This simple change makes the audio tracks invisible to most music player applications. It's not clear why this works, but the most likely explanation is that the behavior is a quirk in the way the Windows CD audio driver handles discs with multiple sessions.
For an added layer of protection, the extraneous track you added to the disc is only 31 frames long. (A frame is 1/75 of a second.) The CD standard requires that tracks be at least 150 frames long. This non-compliant track length will cause errors if you attempt to duplicate the disc with many CD drives and copying applications.
Caveat emptor. Yes, your copy-protected CD is "industrial strength" — XCP and Macrovision employ exactly the same passive protection — but even the pros have their limitations. There are many well-known method for defeating this kind of passive protection, such as:
- Enhanced software – Advanced CD ripping programs avoid the Windows CD audio driver altogether and communicate directly with the CD drive. Thus, programs such as EAC are able to rip the tracks without any difficulty. – Better CD copying applications, including Nero, support a recording mode called Disc-at-Once/96; this lets them create an exact duplicate of the protected disc even though the last track has an illegal length.
- Other operating systems – The discs can be ripped with standard software on Macs and on Linux systems. These platforms don't suffer from the limitation that causes ripping problems on Windows.
- Magic markers – The famous magic marker trick involves carefully drawing around the outer edge of the CD. This blocks out the second session, allowing the disc to be ripped and copied just like an unprotected CD.
And of course, at any time Microsoft could fix the Windows quirk that is the basis for this technique, rendering it completely ineffective.
Despite these limitations, who wouldn't enjoy finding a homemade copy-protected CD in their stocking? They're a great way to spread holiday cheer while preventing anyone else from spreading it further.
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