Zencoder,

You're absolutely right, particularly in your final comments, about scrutinizing my requirements. The development process I'm using right now however is to find the answer to the question I am having most difficulty with -- how to do the authentication -- and then work backwards from that in a test environment through the things I do know how to do until the entire user-to-LAN system is as secure as I want it.

I really just wanted to filter out long-winded discussions of the encryption problem and focus on the authentication problem.

Your comments are very well-taken, and I certainly appreciate a little preaching. After all, this is part of the spirit of AO, isn't it? Educate the problem-solver as well as the problem . . .

As an aside, part of my reason for exploring this problem on my own time is that I am finding that occasionally users have decided that my little WEP key is too much of a hassle for them to configure on their machines and have therefore taken to yanking cables from innocent desktops and plugging them into their machines anyway. Fortunately, this is a closed location so I know that anyone who does this is legit due to physical limitations, but I would like to take advantage of a little more effort on my part in order to discourage misuse of my LAN on their part.