code: protected static function getCURLCerts() {
          $url = 'https://curl.haxx.se/ca/cacert.pem';
          $certs = @file_get_contents($url);
          if (!$certs) {
              $ch = curl_init();
              curl_setopt($ch, CURLOPT_URL, $url);
              curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
              curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, TRUE); // for security this should always be set to true.
              curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);    // for security this should always be set to 2.
              $response = curl_exec($ch);
              $info = curl_getinfo($ch);
              curl_close($ch);
              if ($info['http_code'] == 200) {
                  $certs = $response;
              }
          }
          return $certs;
      }
docs: Get latest CA certs from curl.haxx.se
  
  @return string