【PHP】微信开放平台---消息加解密-php7.1 使用openssl代替Mcrypt

/**
     * 对密文进行解密
     * @param string $encrypted 需要解密的密文
     * @return string 解密得到的明文
     */
    public function decrypt($encrypted, $appid)
    {

        try {
            //使用BASE64对需要解密的字符串进行解码
            $ciphertext_dec = base64_decode($encrypted);
            $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, ‘‘, MCRYPT_MODE_CBC, ‘‘);
            $iv = substr($this->key, 0, 16);
            mcrypt_generic_init($module, $this->key, $iv);

            //解密
            $decrypted = mdecrypt_generic($module, $ciphertext_dec);
            mcrypt_generic_deinit($module);
            mcrypt_module_close($module);
        } catch (Exception $e) {
            return array(ErrorCode::$DecryptAESError, null);
        }


        try {
            //去除补位字符
            $pkc_encoder = new PKCS7Encoder;
            $result = $pkc_encoder->decode($decrypted);
            //去除16位随机字符串,网络字节序和AppId
            if (strlen($result) < 16)
                return "";
            $content = substr($result, 16, strlen($result));
            $len_list = unpack("N", substr($content, 0, 4));
            $xml_len = $len_list[1];
            $xml_content = substr($content, 4, $xml_len);
            $from_appid = substr($content, $xml_len + 4);
        } catch (Exception $e) {
            //print $e;
            return array(ErrorCode::$IllegalBuffer, null);
        }
        if ($from_appid != $appid)
            return array(ErrorCode::$ValidateAppidError, null);
        return array(0, $xml_content);

    }

/**
     * 对密文进行解密
     * @param string $encrypted 需要解密的密文
     * @return string 解密得到的明文
     */
    public function decrypt($encrypted, $appid)
    {

        try {
            $iv = substr($this->key, 0, 16);
            $decrypted = openssl_decrypt(base64_decode($encrypted),‘AES-256-CBC‘,$this->key,OPENSSL_RAW_DATA,$iv);
           
        } catch (Exception $e) {
            return array(ErrorCode::$DecryptAESError, null);
        }
        try {
            //去除补位字符
            $pkc_encoder = new PKCS7Encoder;
            $result = $pkc_encoder->decode($decrypted);
            //去除16位随机字符串,网络字节序和AppId
            if (strlen($result) < 16)
                return "";
            $content = substr($result, 16, strlen($result));
            $len_list = unpack("N", substr($content, 0, 4));
            $xml_len = $len_list[1];
            $xml_content = substr($content, 4, $xml_len);
            $from_appid = substr($content, $xml_len + 4);
         
        } catch (Exception $e) {
            //print $e;
            return array(ErrorCode::$IllegalBuffer, null);
        }
        if ($from_appid != $appid)
            return array(ErrorCode::$ValidateAppidError, null);
        return array(0, $xml_content);

    }