Just for fun, I wrote this script to parse /usr/dict/words looking for long words without repeating letters. Here's the code:

#!/usr/bin/perl -w
use strict;

my @words = ();
my $max_len = 0;
my $delta = 2; # Number of letters less than maximum which is acceptab
+le

while (<>) {
    # Check for words which are too short
    my $cur_len = length;
    next if $cur_len + $delta < $max_len;

    # Check for words with repeating letters
    next if /(.).*\1/;

    # Store value in list, possibly destroying old values
    if ($cur_len > $max_len) {
        $max_len = $cur_len; 
        @words = ($_);
    } else {
        push @words, $_;
    }
}

print @words;
[download]

And if you're curious, here's the output:

ambidextrously
bankruptcies
bluestocking
configurable
considerably
consumptively
copyrightable
customizable
exclusionary
flowcharting
incomputable
productively
questionably
recognizably
unpredictably
unprofitable
upholstering
[download]

A thirteen letter word might work better because you wouldn't have to pad the cypher.

-Ted