php - getting https site through curl

I need to get information from https site, it has http authentication, i did some research and i know that i need to use curl so there is my code

$ch = curl_init();
$url = 'https:/....';
$username ='user';
$password ='userspassword';
curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch,CURLOPT_SSLKEYTYPE,"PEM");
curl_setopt($ch, CURLOPT_USERPWD, "$username:$password");
curl_setopt($ch, CURLOPT_BINARYTRANSFER, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_SSLCERT, '/var/www/cert/ows.pem');
curl_setopt($ch, CURLOPT_SSLCERTPASSWD, ' ');
curl_setopt($ch, CURLOPT_SSLKEY, '/var/www/cert/ssl-cert-snakeoil.pem');
curl_setopt($ch, CURLOPT_SSLKEYPASSWD, ' ');

curl_setopt ($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt ($ch, CURLOPT_SSL_VERIFYPEER, 1);
curl_setopt($ch, CURLOPT_SSLVERSION,3)
Copy code

and i get "unable to set private key file: '/var/www/cert/ssl-cert-snakeoil.pem' type PEM58" if i dont use any pem i get empty response from server, if i do i cant load them.. where i can find sslcert and sslkey on my system? and how to format them correcly, becouse if i export them directly from firefox it.