Security questions

Hi,

first of all let me say thanks for great software, I ve been searching for portable apps a long time.

I have few security questions:

Portable mozilla: if I have passwords keeping in my portable mozilla, doesnt public computer in anyway can get them.

Portable ftp: same goes for this one.

I have this question, as we do regular backups of our portal. We have access to trusted high optical connection computers, but they are in public use, and I am concerned if somebody would install trojan on such computer.

So if this should be the case, and we have on USB for example mozilla stored passwords and we don't type them when we are on public computer, just mouse-click, can somebody get them or not?