In my organisation, I use Portable Keyboard Layout (PKL) extensively. Since it's portable software, you don't need admin privileges to run it. I put it in a directory on my computer (or in my network home area) and then I link to it in the Startup folder so it's automatically run for my user only. Works like a charm (unless your IT department are really nasty...).

Personally, I think it's safe but that depends on how strict your company policy is. You could compile it yourself from the available source code, but you'd have to trust the compiler (AutoHotkey) at least - unless you compile that too! (I think you could get the source code for AHK as well?). At any rate, I haven't had any kind of trouble with it and I've used it for years now.

In the pkl.ini file you can set hotkeys for stopping the program, suspending it and hiding/showing the layout screen. There's also an icon at the lower right (system tray) you can use. To start it... well, you double-click it or do what I said above?