When you purchase music from the Apple iTunes Music Store (ITMS), you can only play the songs on computers which you have authorized by logging into the Music Store. Apple allows you to have up to five computers authorized simultaneously. There is also a mechanism for deauthorizing a computer to free up a slot for later use. This is known as
Digital Rights Management, or DTM.
Stories abound from iTunes-users who have unwittingly used up their five allotments then had a computer go dead on them, or sell it before deauthorizing it. You can petition Apple if you've lost the ability to deauthorize a computer you no longer have access to, but I suspect it's not a simple process. Apple has several pages related to iTunes and Computer Authorization on their Web site for the curious out there. Deauthorizing a computer you have access to is a simple process, just look under iTunes Advanced menu.
Apple's DRM system is named
PlayFair. "
PlayFair" was an Open Source project which used source code written by Jon Lech Johansen to remove the FairPlay DRM encryption in AAC MP4 files. The FairPlay name, while a clever dig at Apple's protection scheme, embodies the beliefs held by proponents of fair-use under copyright law.
Apple Computer issued a cease and desist order to Sourceforge to shut down the PlayFair Web site (http://playfair.sourceforge.net). But now "The PlayFair free software project is back online, with both the maintainer of the project and the hosting service willing to face a legal challenge from Apple." It has a new name as well,
Hear
Your
Music A
nywhere -- Hymn. The Hymn homepage offers the following introduction to their project:
Why use Hymn?- To decrypt your iTunes protected AAC files so that they can be played on operating systems for which no official version of iTunes exists, such as Linux.
- To use non-Apple AAC-capable hardware to play your music.
- To eliminate the five computer limit imposed by iTunes.
- To make archival backups of your music.
- As the first step in converting your music from protected AAC to MP3, Ogg, or your other favorite audio file format, for use with your non-iPod portable audio player.
- To demonstrate your belief in the principles of fair-use under copyright law.
I spent a few minutes tonight with the JHymn software and found it very easy to use (at least running on Mac OS X). It's predominantly Java-based but has a bit of everything under the hood (JNI libraries written in C, the LAME MP3 encoder, and AppleScripts for updating your iTunes library after the protected ACC files are converted). I only converted a single song, but it was quick and after importing back into iTunes, it was exactly the same as the purchased copy except for the PlayFair information.
Click for larger imageHymn runs on Mac OS 10.3.3, Gentoo Linux and Windows XP Pro. There's a Cocoa GUI for Mac OS X, and a command line interface for all supported platforms. A derivative project called iOpener runs on Windows. if you have your iPod mounted on the Desktop, Hymn will locate the key it needs to open up the ACC files, otherwise Hymn will ask you to authorize through the itunes Music Store to get this information.
While Apple will continue to try and thwart users' unrestricted access to their purchased music, for now at least, you have an option to play your music where you want.
Links:The Hymn Web Site:
hymn-project.orgJon Lech Johansen (
nanocrew.net) is the person who first reverse-engineered the FairPlay DRM scheme but is more widely known for his work on DeCSS, which was a program that allowed DVDs to be played on unsupported devices and operating systems.
www.asleep.net/blog/Daeken/2004/08/25/316/ offers a description of the FairPlay DRM Scheme (the Hymn documentation also has an interesting description complete with diagrams. :-)