#!perl -w
use strict;
#use Digest::CRC qw(crc16);
use Digest::MD5 qw(md5);

sub digest {
    return unpack("v", md5(pack("v", shift)));
}
#  example calculating and using rainbow tables

# http://www.ethicalhacker.net/content/view/94/24/
# http://www.antsight.com/zsl/rainbowcrack/

my %x;
my $c=0;
for (my $i=0 ; $i<65536 ; $i++) {
    next if exists $x{$i};
    my $j= $i;
    printf("-----%04x\n", $i);
    while (!exists $x{$j}) {
        $x{$j}{chain}= $c;
        my $n= digest($j);
        $x{$j}{next}= $n;
        $j= $n;
        printf("%04x\n", $j);
    }
    $c++;
}
printf("c=%d\n", $c);

# generate table with:
#
# endhash -> starthash   such that  crypt ... crypt(starthash ) = endhash
sub genrainbow {
    my ($c, $chainlen)= @_;

    
}