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7 line perl script nukes CSS protection.

By Signal 11 in MLP
Fri Mar 09, 2001 at 10:25:20 AM EST
Tags: News (all tags)

Wired is reporting that a 7 line perl script has been created to decrypt CSS-protected DVDs. Anyone wanna take a crack at singing it like someone did with DeCSS?


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7 line perl script nukes CSS protection. | 24 comments (23 topical, 1 editorial, 0 hidden)
Sing it? (3.71 / 7) (#1)
by Seumas on Thu Mar 08, 2001 at 02:31:51 PM EST

Why bother singing it? If a few dozen people use it as a 7-line email tagline (the cause justifies the size), it'll be archived and distributed pretty damn far and wide for eternity.
I just read K5 for the articles.
Because it is entertaining (3.00 / 1) (#7)
by slakhead on Thu Mar 08, 2001 at 04:10:31 PM EST

How do you get any nerdier than singing code though? Well there might be some other ways but I dont care to know about them!

I liked the song though. Definetely worthwhile when bored.

[ Parent ]
Meme propagation (4.00 / 1) (#17)
by fluffy grue on Fri Mar 09, 2001 at 01:42:18 PM EST

Because songs tend to be much easier to remember. I sometimes find myself with descramble.mp3 stuck in my head, with some of the actual "lyrics" going through my head. When the code is presented as catchy song lyrics, it becomes rather difficult to forget them - making everyone who hears it a potential information carrier.

Also, the sung version predates this 7-line tagline by quite a bit.
"Is not a quine" is not a quine.
I have a master's degree in science!

[ Hug Your Trikuare ]
[ Parent ]

Damn. (4.42 / 7) (#2)
by darthaya on Thu Mar 08, 2001 at 02:41:04 PM EST

The signature on k5 is not long enough to contain all the code.

But a comment field is (5.00 / 1) (#13)
by onyxruby on Thu Mar 08, 2001 at 08:29:46 PM EST

#!/usr/bin/perl -w # 531-byte qrpff-fast, Keith Winstein and Marc Horowitz <sipb-iap-dvd@mit.edu> # MPEG 2 PS VOB file on stdin -> descrambled output on stdout # arguments: title key bytes in least to most-significant order $_='while(read+STDIN,$_,2048){$a=29;$b=73;$c=142;$t=255;@t=map{$_%16or$t^=$c^=( $m=(11,10,116,100,11,122,20,100)[$_/16%8])&110;$t^=(72,@z=(64,72,$a^=12*($_%16 -2?0:$m&17)),$b^=$_%64?12:0,@z)[$_%8]}(16..271);if((@a=unx"C*",$_)[20]&48){$h =5;$_=unxb24,join"",@b=map{xB8,unxb8,chr($_^$a[--$h+84])}@ARGV;s/...$/1$&/;$ d=unxV,xb25,$_;$e=256|(ord$b[4])<<9|ord$b[3];$d=$d>>8^($f=$t&($d>>12^$d>>4^ $d^$d/8))<<17,$e=$e>>8^($t&($g=($q=$e>>14&7^$e)^$q*8^$q<<6))<<9,$_=$t[$_]^ (($h>>=8)+=$f+(~$g&$t))for@a[128..$#a]}print+x"C*",@a}';s/x/pack+/g;eval

The moon is covered with the results of astronomical odds.
[ Parent ]

perl eh, you've got to laugh! (2.66 / 3) (#15)
by codemonkey_uk on Fri Mar 09, 2001 at 05:52:23 AM EST

Is it deliberatly obsficated or does Perl always look like that? :)

If I produced code like that at work the other programmers would take me outside and beat me.

And this comming from someone who entered the IOCCC...
"The most savage controversies are those about matters as to which there is no good evidence either way." - Bertrand Russell
[ Parent ]

Not exaclty 7 lines.. (3.00 / 4) (#3)
by argent on Thu Mar 08, 2001 at 02:42:53 PM EST

I saw this yesterday. This truly counts as obsfucated perl. It's 7 lines since the author places several commands on a single line, significantly shortening the physical space it takes up when typed out.
I also saw the code after someone "expanded" it, and applied nesting rules, etc. and it was still dammed impressive.

This beats the hell out of the "lets encrypt mp3 files names with pig latin" bullshit that was getting attention for supposedly beating the RIAA with it's own DMCA rules.

cd /pub more Beer
igP atinL (4.00 / 1) (#18)
by fluffy grue on Fri Mar 09, 2001 at 01:45:35 PM EST

It wasn't even proper pig latin, and it's pretty funny how the people doing it seemed to think that pig latin was "secure" and such. I would have preferred to see something like automatic h4x0r-5p33k conversion; the whole reason that h4x0r-5p33k came around to begin with was to get around content filters on BBS messageboards and chat systems (which, of course, most of the people speaking it have never even heard of).

It's also pretty funny how they thought that their teachers couldn't understand them, and that it was a novel concept. Come on, even when I was an angsty adolescent I didn't think my teachers were that dumb. :P
"Is not a quine" is not a quine.
I have a master's degree in science!

[ Hug Your Trikuare ]
[ Parent ]

Pig Latin (none / 0) (#22)
by PresJPolk on Sat Mar 10, 2001 at 01:19:31 AM EST

The point wasn't that Pig Latin was secure. The point was that according to the DMCA, breaking a content protection scheme is illegal, regardless of whether it's a secure method.

If the law required that things actually had to be secure, the issue would be moot. If DVD decryption were harder, then DeCSS wouldn't exist.

[ Parent ]
OT:Perl (4.00 / 5) (#4)
by ucblockhead on Thu Mar 08, 2001 at 02:50:07 PM EST

Offtopic, but I just thought I'd pass on something amusing I noticed when I saw this yesterday. I ran gzip on it, and it was only able to reduce the size by about 20%! Gotta love Perl...
This is k5. We're all tools - duxup
DCMA (4.00 / 6) (#5)
by Pac on Thu Mar 08, 2001 at 02:53:34 PM EST

Please note that under DCMA it is probably illegal to understand this program. You would be circunventing the protection mechanism... :)

Evolution doesn't take prisoners

DMCA (4.00 / 1) (#12)
by qslack on Thu Mar 08, 2001 at 07:43:13 PM EST

It's DMCA just so you know...not DCMA.

[ Parent ]
"Preview" is my friend (none / 0) (#20)
by Pac on Fri Mar 09, 2001 at 02:21:22 PM EST

And I believe that actually reading the preview before posting is also advised.

I will try to remember...


Evolution doesn't take prisoners

[ Parent ]
Why? (3.50 / 4) (#6)
by Miniluv on Thu Mar 08, 2001 at 03:15:29 PM EST

Why is this so impressive compared to the one line RSA?

"Its like someone opened my mouth and stuck a fistful of herbs in it." - Tamio Kageyama, Iron Chef 'Battle Eggplant'
Interesting... (4.00 / 6) (#8)
by curious on Thu Mar 08, 2001 at 04:25:11 PM EST

But for added article flavour, add this link:
Scholarly Publication, "Gallery of CSS Descramblers"
Includes such gems as people reading and singing the original DeCSS, a very easy to follow explanation of the process written as an epic haiku poem, ASCII art built from the source, images with the source steganographically encoded inside them, and lots of other goodies. My personal favourite is the "Not the DeCSS source." entry.

Enjoy! And remember, if I paid for it, I intend to watch it. On any equipment I can make work. :-P


"Got History?" -- The Prelinger Archive of Ephemeral Movies.

For those of us needing guidance... (4.00 / 1) (#10)
by ignatiusst on Thu Mar 08, 2001 at 04:54:23 PM EST

From Gallery of CSS Descramblers:
The programs take a five-byte title key (see here) on the command line (five decimal numbers, in least to most-significant order) and an MPEG 2 Program Stream VOB file on stdin, and output a decrypted version of the VOB file. For example, to play The Matrix: cat /mnt/dvd/VOB_FILE_NAME | qrpff 153 2 8 105 225 | extract_mpeg2 | mpeg2dec -

When a true genius appears in the world, you may know him by this sign, that the dunces are all in confederacy against him. -- Jonathan Swift
[ Parent ]

Name of the script is qrpff (3.66 / 3) (#11)
by hugorune on Thu Mar 08, 2001 at 05:51:25 PM EST

Try running that through ROT13 encoding and you'll see where this name came from :-)
Phil Harrison
ROT13 (4.00 / 1) (#19)
by DrEvil on Fri Mar 09, 2001 at 01:47:03 PM EST

Does that mean we have to run the script through ROT13 as well?
It might actaully be readable that way.

[ Parent ]
Protected by the DMCA? (4.00 / 2) (#21)
by lovelace on Fri Mar 09, 2001 at 04:35:54 PM EST

Hey, does that mean the MPAA, if they try to claim this a form of DeCSS, can be charged with circumventing the technological measure protecting the name of this script. :-)

[ Parent ]
I was thinking... (2.00 / 1) (#14)
by Zeram on Thu Mar 08, 2001 at 10:07:19 PM EST

More along the lines of having it tattooed on my fingers so I can stick it up the collective asses of the MPAA but most speciffically Jack Valenti.
Like Anime? In the Philly metro area? Welcome to the machine...
Shirt (3.00 / 1) (#16)
by jzuska on Fri Mar 09, 2001 at 12:18:47 PM EST

When is thinkgeek, etc. going to put out a shirt for this?
-- This is not Nam. This is bowling. There are rules. -Walter (The Big Lebowski)
What about the c version? (5.00 / 1) (#23)
by dave114 on Sun Mar 11, 2001 at 01:58:11 AM EST

Thinking that a 472 byte perl implementation was great I jogged down to the Gallery of CSS Descramblers and ran across a copy of what is purported to be the smallest c implementation.

The smallest available C implementation at solely 446 bytes seems more impressive to me. As well it is significantly faster. Why can't people appreciate some of the incomprehensible Greek that can be another language's programs?

No new lines were har^H^H^Hcounted in the creation of this comment

Hmm (none / 0) (#24)
by Elendale on Sun Mar 11, 2001 at 04:50:44 PM EST

How interesting. I think i'm starting to see where "The Man" is coming from on this. It seems like they're arguing that creating a program is no different than writing the floor plans for a building, or drafting the technical documents for a new weapon. More than that, it seems they are saying its expression (as in, deliberately saying something with what you do) that counts as free- not the ability to actually say something. In this way, i could see where they would say source code is not protected by first ammendament rights- but then wouldn't something like defacement of the RIAA's homepage count as expression? After all, flag burning was ruled speech a few years back in Texas. Sounds like the result they weren't looking for :) Of course, i could be wrong. It hurts my head to think like that...


When free speech is outlawed, only criminals will complain.

7 line perl script nukes CSS protection. | 24 comments (23 topical, 1 editorial, 0 hidden)
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