Configuré un servidor local usando XAMPP. Tengo dos scripts PHP, un remitente y un receptor. Estoy intentando enviar un archivo XML del remitente al receptor mediante HTTP a través de SSL (HTTPS).

Creé un certificado autofirmado, configuré XAMPP y estoy usando este código en mi remitente:

<?php
  /*
   * XML Sender/Client.
   */
  // Get our XML. You can declare it here or even load a file.


  $xml = file_get_contents("data.xml");

  // We send XML via CURL using POST with a http header of text/xml.
  $ch = curl_init();

  //curl_setopt($ch, CURLOPT_SSLVERSION,3);

  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
  curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);

  curl_setopt($ch, CURLOPT_CAINFO,  getcwd().'ipm.crt');
  curl_setopt($ch, CURLOPT_SSLCERT, getcwd().'ipm.pem');

  curl_setopt($ch, CURLOPT_SSLCERTPASSWD,'pass');

  //i use this line only for debugging through fiddler. Must delete after done with debugging.
  curl_setopt($ch, CURLOPT_PROXY, '127.0.0.1:8888');

  // set URL and other appropriate options
  curl_setopt($ch, CURLOPT_URL, "https://ipv4.fiddler/iPM/receiver.php");
  curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: text/xml'));
  curl_setopt($ch, CURLOPT_HEADER, 0);
  curl_setopt($ch, CURLOPT_POST, 1);
  curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0);
  curl_setopt($ch, CURLOPT_REFERER, 'https://ipv4.fiddler/iPM/receiver.php');
  curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
  $ch_result = curl_exec($ch);
  echo "Result = ".$ch_result;

  echo 'Curl error: ' . curl_error($ch);

  curl_close($ch);
  // Print CURL result.
?>

Sin embargo siempre me sale este error:Curl error: unable to use client certificate (no key found or wrong pass phrase?)

¿Qué puedo hacer mal? La frase de paso ES la palabrapass .

Creé mi .crt haciendo:

openssl req -config openssl.cnf -new -out ipm.csr -keyout ipm.pem

openssl rsa -in ipm.pem -out ipm.key

openssl x509 -in ipm.csr -out ipm.crt -req -signkey ipm.key -days 365

No quiero poner elSSL_VERIFYPEER ySSL_VERIFYHOST a falso