[prev in list] [next in list] [prev in thread] [next in thread] 

List:       openbsd-misc
Subject:    Re: Passwords
From:       Dave Feustel <dfeustel () mindspring ! com>
Date:       2002-10-23 11:17:08
[Download RAW message or body]

Marcus,

Thanks for the info. I was only interested in using the alt codes in order
to make my passwords harder to crack. If <alt-nnn> doesn't work with 
Xwindows then I won't be using <alt> codes on OpenBSD.
I
Dave Feustel 
(UofM 1968)

On Wednesday 23 October 2002 09:04 am, Marcus Watts wrote:
> dfeustel@mindspring.com writes:
> > IBM PC keyboards can generate all 256 binary codes.
> > Ascii codes are generated directly by pressing the appropriate key.
> > The additional 128 codes can be generated by holding down the <alt>
> > key and then entering a 3-digit decimal number (<alt>-nnn) using the
> > numeric keypad. Windows accepts those <alt> codes for passwords
> > and so does the passwd and login program in OpenBSD. But the Xlock
> > program didn't accept my password containing <alt>-nnn characters.
>
> Actually, IBM PC keyboards don't do that.  They send up/down codes via
> one of several strange serial interfaces.  The smarter ones can run in
> several different modes and generate (at least) AT and XT keycodes.
> USB keyboards are probably even more complicated.  The <Alt>-nnn
> protocol is a function of the host computer keyboard device driver.
> Since the original 8088-based IBM PC bios supported the <Alt> thing to
> send "all 256 ascii codes", most DOS or windows based keyboard software
> since has also done so (how this all maps into function key codes,
> international keyboards, and worse yet, wide characters in
> international character sets which aren't ascii and have many more than
> 256 characters is probably all quite messy, though I've heard stories
> that this is one area where MicroSoft has actually expended some
> effort.)
>
> Unfortunately for you, the X server keyboard interface comes from a
> completely different evolutionary path.  In the X world, keyboards
> don't generate ASCII codes, they generate keyboard up/down codes.
> Software somewhere else manages keyboard state transitions, completely
> independently of any software the host computer might otherwise offer
> when X is not running.  Basically the whole idea of trapping keystate &
> generating binary data is completely alien to X, and X programmers will
> give you strange stares if you insist this is important.  In the world
> of X, it's more important that keys generate the data that's printed on
> the label, and it's acceptable that if you don't have a meta or <esc>
> or X key, you don't get to type meta, <esc> or X.
>
> Actually, though, I can't find any evidence that openbsd is *ever*
> willing to do the ALT-nnn thing.  At least, if I type things into the
> shell, or an xterm, alt-numpad7 and alt-7 both generate stuff right
> away without waiting to see if I type another digit.
>
> 				-Marcus Watts

-- 
Dave Feustel
http://www.mindspring.com/~dfeustel/recentactivities.html

[prev in list] [next in list] [prev in thread] [next in thread]