Level 14

The following function defines the login process

function pwCheck($guid,$password)
{
	if(!$guid || !$password) return false;
    $users = implode(file('/data/login_info.json'));
	$json = json_decode($users,true);

	foreach($json['result'] as $data)
		if($data['guid']==$guid && $data['password'] == $password && $data['account_status']=='active')
			return true;
	return false;
}

GUID

Password