HidePass от Ross Hill

HidePass is a security extension which hides the asterisks normally shown when entering a password, so that the length of one's password cannot be determined. An attacker knowing the length of one's password greatly decreases the number of guesses the attacker has to do in order to crack your password. Hiding the length of your password prevents this. This is especially helpful for those who need to enter their passwords while their screen is on projector.