google repatcha返回false，原因是“；无效输入秘密”；

我已经从谷歌安装了最新的repatcha，但它在提交后总是返回false，并且总是返回"无效输入机密"错误，即使从前端视图来看验证总是正确的。这可能是什么原因。顺便说一句，我正在用phalcon框架测试localhost examplep中的所有内容。这是我检查captcha:的部分

protected function validate_data($post, $ip){
    $validation = new Validation();
    $validation->add(
        'user_name',
        new PresenceOf(
            array(
                'message' => 'The Username is required'
            )
        )
    );
    $validation->add(
        'email',
        new PresenceOf(
            array(
                'message' => 'The e-mail is required'
            )
        )
    );
    $validation->add(
        'password',
        new PresenceOf(
            array(
                'message' => 'The Password is required'
            )
        )
    );
    $validation->add(
        'cpassword',
        new PresenceOf(
            array(
                'message' => 'The Confirmation Password is required'
            )
        )
    );
    $validation->add(
        'email',
        new Email(
            array(
                'message' => 'The e-mail is not valid'
            )
        )
    );
    $validation->add('password', 
        new Confirmation(array(
           'message' => 'Password doesn''t match confirmation',
           'with' => 'cpassword'
           )
        )
    );
    $error = $validation->validate($post);
    $errors = array();
    if(count($error)){
        foreach($error as $e){
            $errors[] = $e;
        }
    }
    $data = array(
        'secret' => "my secret key",
        'response' => $post['g-recaptcha-response'],
        'remoteip' => $ip
    );
    $verify = curl_init();
    curl_setopt($verify, CURLOPT_URL, "https://www.google.com/recaptcha/api/siteverify");
    curl_setopt($verify, CURLOPT_POST, true);
    curl_setopt($verify, CURLOPT_POSTFIELDS, http_build_query($data));
    curl_setopt($verify, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($verify, CURLOPT_RETURNTRANSFER, true);
    $res = curl_exec($verify);
    $captcha = json_decode($res);
    if($captcha->success == false){
        $errors[] = "Invalid Captcha, You are a freakin robot!";
    }
    return $errors;
}

这可能是什么原因？这是转储响应时的输出：

object(stdClass)#70 (2) { ["success"]=> bool(false) ["error-codes"]=> array(1) { [0]=> string(20) "invalid-input-secret" } }