DeCSS is a piece of free software that provides decryption of DVD video.  This is an essential piece of software for users of Linux and other free software operating systems to watch DVDs.  In the United States, the Digital Millenium Copyright Act (DMCA) has been used against this software and thus unfairly monopolise DVD reading software and limit competition, and new laws may be coming into effect in Australia soon which will import this law into our country.