#!/usr/bin/perl
# xor3.pl - Don Yang (uguu.org)
#
# Test XOR encode with repeative 3 character pattern.
#
# 12/23/07

use strict;

my $code = q{

$l = 23 - 2 * ($a = sin(($n = (time() % 100) / 50) * atan2(0, -1)));
$p = 10.5 + $a;
$q = 6.5 - $a;

if( $n < 1 )
{
   $s = 56 - 33 * $n;
   $x = 2 * $n - 1;
   $t = 11 + $x * $x * 7;
}
else
{
   $s = 23 + 33 * ($n - 1);
   $t = 18;
}

for($y = 0; $y < 24; $y++)
{
   $v = ($y - $t) / ($y < $t ? $p : $q);
   for($x = 0; $x < 79; $x++)
   {
      $u = ($x - $s) / $l;

      $n = $x - int($s);
      $z .=
         chr
         (
            $y == int($t + $q) && abs($x - $s) < 10
            ?  33
            :  (
                  $u * $u + $v * $v > 1 ||
                  ($y > $t - 5 - 2 * $a && $y <= $t - 2 - 2 * $a &&
                   !($n + 6 && $n && $n + 5 && $n - 1))
                  ? 32 : 33
               )
         );
   }
   $z .= "\n";
}

$n = ($z =~ y/!/x/);
$c = '$c=q{' . $c . '#'x($n - length($c) - 26) . '};$c=~s/\s//g;eval$c;';
$y = 0;
foreach $x ($z =~ /./gs)
{
   print 'x' eq $x ? substr($c, $y++, 1) : $x;
}

};

$code =~ s/\s//g;
($code eq lc($code)) or die;
my $size = length($code);
print "code =\n$code\nsize = $size\n";
($size % 3) == 0 or die;

for(my $i = 1; $i < 256; $i++)
{
   for(my $j = 1; $j < 256; $j++)
   {
      for(my $k = 1; $k < 256; $k++)
      {
         my $x = $code ^ ((chr($i) . chr($j) . chr($k)) x ($size / 3));
         my $c = 0;
         for(; $c < $size; $c++)
         {
            my $a = ord(substr($x, $c, 1));
            if( $a <= 32 || $a >= 127 )
            {
               last;
            }
         }
         if( $c == $size )
         {
            printf '0x%02x 0x%02x 0x%02x', $i, $j, $k;
            print "\n$x\n";
         }
      }
   }
}