Content only for reg. users – but post title visible for everyone!

Hello,

I’d like to show all post titles on my site (e.g in the sidebar) – but to read the complete post (=content), visitors shall have to login (are forwarded to login form).

Is there a plugin that is able to do that (let the title stay visibile!)? I couldn’t found one.
I don’t need a complex membership plugin with profiles etc. – the standard wp user function is adequate.

Thanks for any help and all the best for the new year!
Stefan