Re: [dvd-discuss] Comparing DeCSS with legitimate code.

[Jeremy Erwin <jerwin(at)ponymail.com>]

On Thursday, May 23, 2002, at 06:54  PM, Mark Roberts wrote:
>
>
> Since there is NO difference between DeCSS and any code whichj 
> legitimately retrieves information from a DVD player, it cannot be said 
> that DeCSS breaches the DMCA, as it specifically meets the provisions 
> of 1201.(2)(A) and 1201.(2).(B)
>
>
There are three systems at issue here,

DeCSS (and css_cat): system is used to copy plaintext VOBs to disk.
libcss: system is intended to feed into ac3, mpeg2 decoders for 
immediate playback
CSS: the officially licensed spec

Since plaintext transfer of VOBs to hard disk was not envisoned as a 
legitimate operation by the inventors of CSS, DeCSS arguably circumvents.

Assuming that libcss is an clone of officially sanctioned sytems 
(possibly verifiable, as IIRC, CSS's code has been publicly disclosed, 
if only by accident), libcss does not circumvent, assuming that keys 
have been obtained legitimately.

There are two versions of the CSS algorithm. One uses a known key-- the 
other uses a brute force method. The latter version is closest to 
circumvention, as it dispenses  with the toy cryptography-- and uses a 
digital pickgun instead. The former system masquerades as a "authorized" 
player, and uses a legitimate key. Is this circumvention? I really don't 
know.

Jeremy