I've been playing a bit with Lighttpd and PHP to serve up some local files with MobileSafari, and it's great stuff, but as a total newbie to this, I have some questions.

I'm wondering about security & power usage.

Security: Anybody on my network can log right into the directory, which is handy on occasions, but clearly poses a security risk. How do I add authentication? There's nothing terribly interesting there, I'm just using it to host some web apps locally and serve up some PDFs for now, but it would be nice to secure it.

Power: Has anybody looked to see what kind of extra battery drain the server causes? Is it significant or negligible?

Thanks to anyone who can shed some light on this for me!