my $new_c;
        if ($c =~ /[a-z]/i) {
            $new_c =  $abc[($abc{lc($c)} + $key[$i]) % 26];
            $new_c = uc($new_c) if ($c =~ /[A-Z]/);
            $result .= $new_c;
            $i = ($i + 1) % @key;
        } else {
            $result .= $c;
        }