[WEB4LIB] RE: Gray Hats Re: Re: Jack Valenti: Copyright and

[Chris Deweese]

Tony,
I believe you refer to this :)
"DVD descrambler encoded in 'illegal' prime number"
http://www.theregister.co.uk/content/6/17681.html
I wont post the number tho ;) j/j
Good to see there some humor out there about this subject.

Chris D
----- Original Message -----
From: "Tony Barry" <me at Tony-Barry.emu.id.au>
To: <chrisd at lcls.org>
Cc: "Multiple recipients of list" <web4lib at webjunction.org>
Sent: Tuesday, March 20, 2001 20.21
Subject: [WEB4LIB] RE: Gray Hats Re: Re: Jack Valenti: Copyright and


> At 2:53 PM -0800 20/3/01, Chris Deweese wrote:
> >Again we see hacking being classified in a "dark" manner.  As matt
> >said, hacking is about the method and not the context.  Might I
> >suggest this story:
> >Seven-Line Perl code beats DVD Crypto
> >http://www.theregister.co.uk/content/4/17444.html
> >A seven-line program written in perl script beats the MPAA's DVD
> >encryption scheme.  The program was written by a former MIT student
> >and a currnet undergrad.  A pure example of hacking being about the
> >method.
> >These guys didnt write this program to copy dvd's.  They wrote it to
> >prove how weak the system currently used is.  deCSS the original
> >program to decrypt dvds was written by a 15 year old kid.
> >I see no wrong doing in this.  But the MPAA has been in an uproar
> >about it.  Why? Because it shows how little money they really
> >invested in coming up with a copy protection system.  More money is
> >probably invested in child safety caps for medicine.(thats a guess
> >not a fact)
>
> The code is -
>
> #!/usr/bin/perl -w
> # 531-byte qrpff-fast, Keith Winstein and Marc Horowitz
<sipb-iap-dvd at 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;$t^=(72, at z=(64,72,$a^=12*($_%
16
> -2?0:$m&17)),$b^=$_%64?12:0, at z)[$_%8]}(16..271);if((@a=unx"C*",$_)[20]&48)
{$h
>
=5;$_=unxb24,join"", at 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 at a[128..$#a]}print+x"C*", at a}';s/x/pack+/g;eval
>
> It has also been written as an ever shorter c++ program and(using a
> bit of a trick) as a prime number.
>
> Also the web4lib archives may be in breach of the copyright
> legislation for publishing this ;^)
>
> Tony
> --
> phone  +61 2 6241 7659
> mailto:me at Tony-Barry.emu.id.au
> http://purl.oclc.org/NET/Tony.Barry
>