in reply to GUI question: Prima: password input fields
I've installed Prima years ago, but never got around to trying it out. (It's still on my To-Do list.)
But in the installation is an examples directory, so I looked around in there. If you take a look at the examples/menu.pl script, it shows how you can use the password mode on an input control. I just ran it, and it worked just fine, so give it a look.
You'll also want to look over the other examples when you're trying to figure out a feature. You might also look over the tests as well--I do that in any case for modules when I'm trying to figure out how to make something work.
When your only tool is a hammer, all problems look like your thumb.