#!/usr/bin/perl -w
push(@c,int(rand(5)))for(1..3);
sub ed{
    ($o,$d,$e) = @_;
    for(0..length($o)-1){
        $k = $c[$_ % @c];
        $e .= chr(ord(substr($o, $_, 1)) + ($d?$k:-$k));
    }
    return $e;
}

my $message = "Hello, how are you?";
my $encoded = ed($message, 1);
my $decoded = ed($encoded, 0);

print "$message\n";
print "$encoded\n";
print "$decoded\n";