I have a site written in mostly php and html. I also have a sql database of personal information like names and addresses. I would like my users to be able to log in to my website with a login I can email or snail mail to them, and view and edit their information on my database. Users can currently enter information online I and store it in my database but they can't view or edit stored information.

I can add the code to do this, but when I give users the ability to view information I suddenly have a lot more security concerns. Is there an open source package to deal with allowing users to do something like this? Or is there an established convention for this?

I know this is a pretty basic question, and there might be some good literature about it that I have yet to find, so if someone can just point me in the direction of some of that information, or better yet give me firsthand some information about this that would be great.