protected function createNTLMPassword($password, $challenge)
    {
        // FIRST PART
        $ntlmHash = $this->createByte($this->md4Encrypt($password), 21, false);
        list($key1, $key2, $key3) = str_split($ntlmHash, 7);

        $desKey1 = $this->createDesKey($key1);
        $desKey2 = $this->createDesKey($key2);
        $desKey3 = $this->createDesKey($key3);

        return $this->desEncrypt($challenge, $desKey1).$this->desEncrypt($challenge, $desKey2).$this->desEncrypt($challenge, $desKey3);
    }