protected function _base32Encode($secret, $padding = true)
    {
        if (empty($secret)) return '';

        $base32chars = $this->_getBase32LookupTable();

        $secret = str_split($secret);
        $binaryString = "";
        for ($i = 0; $i < count($secret); $i++) {
            $binaryString .= str_pad(base_convert(ord($secret[$i]), 10, 2), 8, '0', STR_PAD_LEFT);
        }
        $fiveBitBinaryArray = str_split($binaryString, 5);
        $base32 = "";
        $i = 0;
        while ($i < count($fiveBitBinaryArray)) {
            $base32 .= $base32chars[base_convert(str_pad($fiveBitBinaryArray[$i], 5, '0'), 2, 10)];
            $i++;
        }
        if ($padding && ($x = strlen($binaryString) % 40) != 0) {
            if ($x == 8) $base32 .= str_repeat($base32chars[32], 6);
            elseif ($x == 16) $base32 .= str_repeat($base32chars[32], 4);
            elseif ($x == 24) $base32 .= str_repeat($base32chars[32], 3);
            elseif ($x == 32) $base32 .= $base32chars[32];
        }
        return $base32;
    }