I'm not clear on why you would do this. Once the "bad guy" figures out what you've done:

open(DICT,"/usr/dict/words");
while(<DICT>) {
     chomp;
     my $guess=crypt($_,$_);
     # insert some LWP code here to attack
     # the web page
     if ($it_worked) {
         print "$user: crypted password is $guess\n";
     }
}

close DICT;
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On the other hand, if you randomize the salt, the loop above becomes an inner loop. Then the "bad guy" has to add an outer loop that runs up to 64*64 times.