gistfile1.txt

this works :

$ curl -k --cert mag.pem:abcd https://something

php code does not work :

<?php
$url = "https://something";

// Create a stream
$opts = array(
  
	'ssl' => array(
	'local_cert' => 'mag.pem' ,
     	'passphrase' => 'abcd' ,
  	) ,
);

$context = stream_context_create($opts);
$content = file_get_contents( $url , false, $context);
echo $content;

it says :
HTTP Error 403.7 - Forbidden: SSL client certificate is required.<br>Internet Information Services (IIS)