++ Great snippet, I actually have a use for this.
May I suggest inserting the following, just before your 'use Term::ReadKey;' line?

$|=1; #Turn on AutoFlush
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On my system (Sun solaris 9 perl 5.8.0) I was consistently seeing 1 less asterisk until I hit the enter key. This should provide a little less confusion for folks entering passwords and not seeing asterisks echoed immediately.
Thanks.