I've found that most of user authentication programs that used in Ubuntu is not gksu, but it's not a problem. The problem is that these programs do not lock the keyboard (while gksu does).
For example, the program
xneur (analog puntoswitcher) can log keystrokes. And when I turn on this option, I found my password used to authenticate applications in this log.
Why is Ubuntu using such an insecure method of authentication? Is there a specific reason why applications don't use
gksu to authenticate? If so, why, if not, shouldn't measures be taken to ensure that applications use
gksu to authenticate?