<? 			$key='6Leh6QkUAAAAAHqPGyUKuk01jkdyPuKA-xxxxxx';
$secret='6Leh6QkUAAAAANOZTunwxOeXAHbxkMN_xxxxxxxxxxx';
$recaptcha=$_POST['g-recaptcha-response'];
function getCurlData($url)
{
 $curl = curl_init();
 curl_setopt($curl, CURLOPT_URL, $url);
 curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($curl, CURLOPT_TIMEOUT, 10);
 curl_setopt($curl, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.16) Gecko/20110319 Firefox/3.6.16");
 $curlData = curl_exec($curl);
 curl_close($curl);
 return $curlData;
}
$google_url="https://www.google.com/recaptcha/api/siteverify";
$ip=$_SERVER['REMOTE_ADDR'];
$url=$google_url."?secret=".$secret."&response=".$recaptcha."&remoteip=".$ip;
$res=getCurlData($url);
$res= json_decode($res, true);

if ($res['success']) { 
// captcha doğru ise
} else {
echo "captcha hatali";
}
?>