I'm using Fluxbox as my window manager, and whenever I want to lock my session, I use xlock while I'm away. However, it seems easy enough for a potentially malicious user to simply switch to the TTY that's running my Fluxbox session and use something like ctrl-c to kill it, gaining access to my logon through the TTY.
I've been looking for a solution to the issue, and it seems that the best I've come up with is to use vlock with the -n flag. (This switches from X to a new terminal, then locks all terminals.) This seems like an ideal solution when I want no one accessing my computer, but what if I want it to be accessible to other users while restricting them from my own login?

Hi...

From your description, it seems that you run Fluxbox directly from "startx" command. And of course if anyone could get into the console session that runs startx, Ctrl-C could kill it.

I see 2 solutions here:
1. Use graphical login manager such as xdm, gdm or Slim, so that Fluxbox is invoked outside tty/console session.

2. Before running "startx", first run "screen". Password this screen session so no one but you could re-attach to this session. The invoke "startx". Once fluxbox has been running, simply go back to screen session and detach. And then log out.

Hope it helps...