A mathematician has calculated a prime number of over 1,000 digits
in length that can be used to represent a piece of illegal code
that breaks DVD encryption. Can displaying a number on-line breach
a court order against the original code?
DVDs are protected by CSS (Content Scrambling System) to encrypt
their contents and prevent copying. The CSS code is licensed to
makers of DVD players. Code to decrypt DVDs, called DeCSS, was
written by a Norwegian teenager and posted on-line. The Motion
Picture Association of America took legal action and succeeded in
having the DeCSS code removed from some sites. As a result, it is
now illegal under US law for any site to display the DeCSS code or
to link to it.
Under the terms of the US court’s order, the illegal DeCSS code
was defined by the court as:
"any computer program, file or device that
may be used to decrypt or unscramble the contents of DVDs that are
protected, or otherwise to circumvent the protection afforded, by
CSS and that permits the copying of the contents or any portion
thereof."
On the basis that any software can be represented as a sequence
of binary bits, mathematician Phil Carmody has represented DeCSS as
a prime number. This presents the challenge of whether a number can
constitute a program, file or device.
