In recent years, the use of optical information storage discs, more colloquially known as "compact discs", "CD-ROMs", "CDs" or "DVDs" has increased in popularity across various industries. Music and computer software are regularly distributed on compact discs. Feature-length films are also beginning to be distributed on compact discs.
One of the major issues facing the music, software, and movie industries as distribution of such products on compact discs becomes more popular is the prevalence of unauthorized copying, or "pirating", of original compact discs. Compact disc pirating around the world cuts sharply into sales and royalties to music, software, and movie developers and manufacturers. As duplicating equipment has become cheaper and more accessible, compact disc pirating has increased dramatically. Therefore, it is desirable to employ a method to discourage or eliminate compact disc pirating.
In the field of computer software, some have attempted to curb compact disc pirating by incorporating unique machine-readable serial numbers on each compact disc manufactured. A human-readable version of the same serial number is distributed in the software packaging, such as in the user-manual. When the user installs the software on a computer, the installation algorithm asks the user to input the serial number. The installation algorithm then compares the user-input serial number to the machine-readable serial number on the compact disc. If they match, the user is permitted to continue installation of the software. If they do not match, an error message is displayed, and the installation algorithm stops. This method is intended to curb compact disc pirating by requiring the user to have a piece of information (the serial number) that is not an integral part of the compact disc itself. Those wishing to pirate compact discs employing this method can easily get around this method by distributing the human-readable serial number along with the pirated compact discs. Furthermore, this method of curbing pirating is not suitable for music or movie compact discs.