#!/usr/bin/env perl 

use strict;
use warnings;
use Data::Dumper;
use List::Util qw( shuffle );

my $str = shift || 'The impatient fox jumped over the lazy camel with hubris.';

my( @codes, %encode );
my @base = ('a' .. 'z', 'A' .. 'Z', 0 .. 9);

for my $i (@base) {
    push @codes, $i;
    for my $j (@base) {
        push @codes, "$i$j";
        for my $k (@base) {
            push @codes, "$i$j$k";
        }
    }
}

@codes = shuffle @codes;

for (split /\s+/, $str) {
    $encode{$_} = shift @codes;
}

$str =~ s/([A-Za-z0-9.]+)/$encode{$1}/eg;
print $str,$/;

my %decodes = reverse %encode;
$str =~ s/(\w+)/$decodes{$1}/eg;
print $str,$/;