could not load PEM client certificate, OpenSSL
<p>I have four files provided from client side.</p>

<ul>
<li>test.jks </li>
<li>test.pem </li>
<li>key.pub </li>
<li>test.p12 </li>
</ul>

<p>I have to send json array on this url using curl. so i'm confused what is the use of other files ? like .p12 , .jks. what is the key from above files ?
I started with .pem file included using this link  :
<a href="https://stackoverflow.com/questions/33880306/how-to-send-a-curl-request-with-pem-certificate-via-php">How to send a curl request with pem certificate via PHP?</a></p>

<p>So , I got following errors.</p>

<p>Error : </p>

<blockquote>
  <p>Curl Error: could not load PEM client certificate, OpenSSL error
  error:0906D06C:PEM routines:PEM_read_bio:no start line, (no key found,
  wrong pass phrase, or wrong file format?)No HTTP code was returned</p>
</blockquote>

<p>Code : </p>

<pre><code>$url = "https://adfapi.adftest.rightmove.com/v1/property/sendpropertydetails";
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);

$pemFile = tmpfile();
fwrite($pemFile, "test.pem");//the path for the pem file
$tempPemPath = stream_get_meta_data($pemFile);
$tempPemPath = $tempPemPath['uri'];
curl_setopt($ch, CURLOPT_SSLCERT, $tempPemPath); 

//curl_setopt($ch, CURLOPT_SSLCERT, "test.pem" );
curl_setopt($ch,CURLOPT_SSLCERTTYPE,"PEM");

curl_setopt($ch, CURLOPT_RETURNTRANSFER, True);
curl_setopt($ch, CURLOPT_POST, True);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, $json_data);
curl_setopt($ch, CURLOPT_VERBOSE, true);

$result = curl_exec($ch);

if(!$result)
{
    echo "Curl Error: " . curl_error($ch);
}
else
{
    echo "Success: ". $result;
}

  $info = curl_getinfo($ch);

  curl_close($ch); // close cURL handler

  if (empty($info['http_code'])) {
          die("No HTTP code was returned"); 
  } else {
      // load the HTTP codes
      $http_codes = parse_ini_file("path/to/the/ini/file/I/pasted/above");

      // echo results
      echo "The server responded: &lt;br /&gt;";
      echo $info['http_code'] . " " . $http_codes[$info['http_code']];
  }
</code></pre>