Use clientside ssl certificate with curl and php

Clientside certificates are often used in soap webservices. For example the wsdl file link might require a clientside certificate. The server throws an error like this :

Curl Command

To use clientside certificate with curl , test the following command

The above command should fetch the protected page which required the clientside certificate.

Php Code

Once the above command works, the equivalent code in php would be :

<?php

$url = "https://www.example.com/some_protected_page";
$cert_file = 'certificate_file.pem';
$cert_password = 'password';

$ch = curl_init();

$options = array( 
	CURLOPT_RETURNTRANSFER => true,
	//CURLOPT_HEADER         => true,
	CURLOPT_FOLLOWLOCATION => true,
	CURLOPT_SSL_VERIFYHOST => false,
	CURLOPT_SSL_VERIFYPEER => false,
	
	CURLOPT_USERAGENT => 'Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)',
	//CURLOPT_VERBOSE        => true,
	CURLOPT_URL => $url ,
	CURLOPT_SSLCERT => $cert_file ,
	CURLOPT_SSLCERTPASSWD => $cert_password ,
);

curl_setopt_array($ch , $options);

$output = curl_exec($ch);

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

The above code would use the certificate file and the password to fetch the url.

Certificate Formats

SSL certificates come in a variety of formats like cer , pfx , pem etc. When using curl its a good idea to convert pfx certificate files to pem format.

The openssl command can be used to do this.