WWW class with authentication

I don't known whether www class has some authentication method, if somebody will be able to help...

I known that wwwform class exist and its authentication, but I need www class because it has the advantage of its class function LoadFromCacheOrDownload() to use the temporary memory (cache). Equally if wwwform class has some method to use the temporary memory, it will be used for me. I'm sorry for my english Thank you.