If you add the web configuration file to SecretFiles folder, then unauthenticated users are blocked from accessing pages in the folder.
When Forms authentication is enabled, unauthenticated users are automatically redirected to the Login page.
The configuration file denies access to anonymous users.
The ? symbol represents anonymous (unauthenticated) users.
? Represents unauthenticated users.
* Represents all users (unauthenticated or authenticated).
File: SecretFiles\Web.Config