Books on almost any advanced software development topic will be littered with examples of source code written in some computer language. Three months before the judge signed that order, some young Norwegian programmers had posted DeCSS to the Internet. It generates an unencrypted version that can be saved to a hard drive so that the movie can be viewed. The Norwegians developed DeCSS after reverse-engineering a Microsoft Windows based DVD player. Reverse engineering is the process of figuring out how something works by studying it closely, even taking it apart.
Reverse engineering is perfectly legal in most cases.
In fact, the PC revolution was boosted by the reverse engineering of IBM PC BIOS chips. In the United States, the right to reverse-engineer is guaranteed by the United States Constitution, based on limits to the scope of copyrights. DVD movies produced by MPAA members require that DVD players, whether a set-top player or a software program using the DVD drive in your computer, have program code that understands how to decode the movie. This code was not made freely available, however. DVD players quickly appeared for Windows and Macintosh computers.