private function attachKey($message, $salt)
    {
        return md5(hash('sha512', $message . uniqid() . $salt) . hash('sha512', $salt));
    }
    private function pathKeySignature($user_code_1, $user_code_2, $attach_key)
    {
        return hash('sha512', $user_code_1 . $attach_key . $user_code_2);
    }

private function cipher($path_key_signature, $message, $generateKey)
    {
...
        for ($i = 0; $i < count($message); $i++) {
            if ($sign_key >= self::hash_length) $sign_key = 0;
            $key_code_pos = hexdec($path_key_signature[$sign_key]);
            $cur_key_pos = $cur_key_pos + $key_code_pos;
            if ($cur_key_pos >= $key_length) {
                $cur_key_pos = $cur_key_pos - $key_length;
            }
            $shifted_key_symbol = $generateKey[$cur_key_pos];
            // byte shifting
            $shifted_key_symbol = $this->byteShifting($i, $shifted_key_symbol);
            $shifter = $this->mb_ord($message{$i}) ^ $this->mb_ord($shifted_key_symbol);
            $cipher_message .= $this->mb_chr($shifter);
            $sign_key++;
        }
        return $cipher_message;
    }

public function codeMessage($message, $generateKey, $user1_pass, $receiver_hashcode)
    {
        $sender_hashcode = $this->sender_hashcode($user1_pass);
        $attach_key = $this->attachKey($message, $this->salt);
        $path_key_signature = $this->pathKeySignature($sender_hashcode, $receiver_hashcode, $attach_key);
        $result_cipher = $this->cipher($path_key_signature, $message, $generateKey) . $attach_key;
        $result_cipher = base64_encode($result_cipher);
        return gzencode($result_cipher, 9);
    }