CI 2.0 Singlelogin + Newspost

[eluser]Zimooon[/eluser]
Hey guys im using CI now for some days and want to do a hidden Login(only i know the link) with 1 user and 1 password(maybe with change option) and after login the possibilty to add Newspost to my page.
How would you do this? i found some auth stuff but all oldversioned and with register etc which i don't need. Would be nice if you give me a short introduction or stuff.

best regards