简易方法 (不安全)
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
安全方法:
用firefox查出网站的CA certificate,下戴, 然后
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_CAINFO, getcwd() . "/CAcerts/BuiltinObjectToken-EquifaxSecureCA.crt");