PHP cURL returns FALSE on HTTPS

I’m trying to make a bot for: https://coinroll.it/api

From the site:
The Coinroll API is a stateless interface which works over HTTPS. Requests are made using POST variables (application/x-www-form-urlencoded) while responses are encoded in JSON (application/json). A HTTPS connection is required for accessing the API.

I have the following code:

$ch = curl_init();
$data = array('user' => 'xxx', 'password' => 'yyy');
curl_setopt($ch, CURLOPT_URL, 'https://coinroll.it');
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded'));   
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
$result = curl_exec($ch);
echo $result;

When I run this code, it returns a blank page, what am I doing wrong?

EDIT
I don’t actually need to use cURl, if there is a better solution, please tell me.

Answer

You can prevent cURL from trying to verify the SSL certificate by using CURLOPT_VERIFYPEER.

Also set the action in the URL:

$ch = curl_init();
$data = array('user' => 'xxx', 'password' => 'yyy');
curl_setopt($ch, CURLOPT_URL, 'https://coinroll.it/getbalance');
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true); 
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$result = curl_exec($ch);
echo $result;