DeCSS
- What is and history of DeCSS.
DeCSS is a computer program capable of decrypting content
on a DVD video disc encrypted using the Content
Scrambling System (CSS).
Origins and history
DeCSS was devised by persons unknown and released anonymously
on the Internet mailing list LiViD in October 1999. Allegedly,
one of the authors was Norwegian teenager Jon Johansen,
whose home was raided in 2000 by Norwegian police. He was
put on trial in a Norwegian court and faced a possible
jail sentence of two years and large fines, but was acquitted
of all charges in early 2003. However, on March 5, 2003,
a Norwegian appeals court ruled that Johansen would have
to be retried on charges that he violated Norwegian Criminal
Code section 145 (the hacker law). The court said that
arguments filed by the prosecutor and additional evidence
merited another trial. On December 22, 2003, the appeals
court agreed with the acquittal, and on January 5, 2004
Norway's Økokrim decided not to pursue the case
further.
The program was first released on October 6, 1999 when Johansen
posted an announcement of DeCSS 1.1b on the livid-dev mailing
list. Initially, the source code was not available, but it
was leaked before the end of the month. The first release
of DeCSS was preceded by a few weeks by a program called
DoD DVD Speed Ripper from a group called Drink or Die, which
didn't include source code and which apparently did not work
with all DVDs. Drink or Die reportedly disassembled the object
code of the Xing DVD player to obtain a player key. The group
that wrote DeCSS, including Johansen, came to call themselves
Masters of Reverse Engineering and may have obtained information
from Drink or Die.
The CSS decryption source code used in DeCSS was mailed
to Derek Fawcus before DeCSS was released. When the DeCSS
source code was leaked, Fawcus noticed that DeCSS included
his css-auth code in violation of the GNU GPL. When Johansen
was made aware of this, he contacted Fawcus to solve the
issue and was granted a license to use the code in DeCSS
under non-GPL terms.
Johansen was involved in a flamewar with another member
on livid-dev over the GPL violation issue. Johansen was a
FreeBSD supporter and criticized Linux. The main point of
the dispute was that Johansen claimed that he had been granted
a non-GPL license by Fawcus for the css-auth code, while
the other party claimed that he was lying. The flamewar ended
when Fawcus confirmed Johansen's side of the story.
At the end of 2000, a document written by an anonymous author
surfaced on the Internet [1] (http://www.chscene.ch/ccc/decss/decsstruth.txt).
It accuses Johansen of being a liar, slandering Linux and
violating the GPL. The accuracy of the document is in dispute:
Johansen's lawyer was a public defender paid by the Norwegian
state and Matthew Pavlovich, LiViD project leader, testified
in MPAA v. 2600 that UDF under Linux was an issue [2] (http://www.eff.org/IP/Video/MPAA_DVD_cases/20000721_ny_trial_transcript.html).
On January 23, 2004, the DVD CCA dropped the case against
Jon Johansen. [3] (http://www.eff.org/IP/Video/DVDCCA_case/20040122_eff_pr.php)
Technology and derived works
The release of the DeCSS source code was the first time the
algorithm of CSS was available for public scrutiny, and it
was soon found to be susceptible to a brute force attack
quite different from DeCSS. The encryption is only 40 bit,
and does not use all keys; a high-end home computer running
optimized code is able to brute-force it in 24 hours quite
easily.
DeCSS was used as a guide by programmers around the world
to create hundreds of equivalent programs, some merely to
demonstrate the trivial ease with which the system could
be bypassed, and others to implement an open source DVD player
(the licensing restrictions on CSS makes it impossible to
create an open source implementation through official channels).
Since no commercial DVD drivers have been made available
for some open source operating systems, users of those operating
systems require an open source implementation in order to
play legally purchased DVDs on legally purchased hardware
and software. However, once the unencrypted source video
is available in digital form, it can be copied without degradation;
thus it is also possible to use DeCSS as part of a scheme
to copy DVD videos to another medium with no loss of quality,
a facility that may encourage mass copyright infringement.
Critics point out that commercial-scale pirating of CSS encrypted
DVDs was widespread in east Asia and elsewhere, and that
this was done without use of DeCSS by individuals or by any
similar techniques, since it is believed that these discs
were simply bit-for-bit copies of the original DVD, with
no need for any decryption of the CSS-encrypted content.
Note that this type of piracy is not possible using standard
recordable DVD blanks, since the section of the DVD that
contains the CSS keys is unwritable.
Legal response
In protest against legislation that prohibits publication
of DeCSS code in countries that implement the WIPO Copyright
Treaty (such as the United States' Digital Millennium Copyright
Act), some have devised clever ways of distributing descriptions
of the DeCSS algorithm, such as through steganography, through
various Internet protocols, as a series of haiku poems, and
even as a so-called illegal prime number. However, due to
the length and number of tables in the CSS algorithm, it
has not been distributed by some of the more "inventive" methods
used to distribute the RSA algorithm during the days of ITAR — it
is not suitable for tattoos, email sigs, etc.
As of 2005, DeCSS (and several copycat programs which have
not been specifically brought to court) can be readily obtained
over the Internet. Some Linux distributions are able to install
a DVD player incorporating a CSS implementation with a single
command.
The first legal threats against sites hosting DeCSS, and
the beginning of the DeCSS mirroring campaign, began in about
early November 1999 (Universal v. Reimerdes). As a response
to these threats a program also called DeCSS but with an
unrelated function was developed [4] (http://www.pigdog.org/decss/).
This program can be used for stripping Cascading Style Sheets
tags from an HTML page. In one case, a school removed a student's
webpage that included a copy of this program, mistaking it
for the original DeCSS program, and received a great deal
of negative media attention.
Source: http://en.wikipedia.org/
