I think that HTTP-Authentication is the way to go. That's how I set up all my sites and it's working really well.

You don't even have to know how the authentication algorithm works, since all you have to do is write a small CGI wrapper around htpasswd so people can add themselves. After successfull authentication you can find the username in the REMOTE_USER environment variable.

But, passwords will be submited unencripted, so if you make something important you might want to use some encrypted, like an SSL server or MD5-Digest authentication.

Doing HTTP authentication in perl isn't hard either: You have to send an header with the status 403 (Unauthorized) which will pop up the username/password dialog on the client side. Then you have to look for the "Http-authentication" (or something like this) header field which contains (BASE64 encoded) "username:password". There you go :)

-octo-