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From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 18 Feb 2015 09:29:04 +0100
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Subject: Re: [Qemu-devel] [PATCH 0/3] SPICE/VNC: Allow ticketing on the fly
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To: Michal Privoznik <mprivozn@redhat.com>
Cc: qemu-devel@nongnu.org, armbru@redhat.com

On Di, 2015-02-17 at 17:40 +0100, Michal Privoznik wrote:
> Currently, if the ticketing (password) is not set at the command
> line, there's no way how to set it afterwards. Or vice versa -
> disable previously set password. I think it's worth allowing
> users to do that. The use case may be a teacher, who wants to
> share a graphical session with students, but has to set up the
> environment firstly. So he starts with a password, and then
> remove it and let students in.

No.  Changing auth scheme as side effect of setting the password is
not going to happen.  It's calling for trouble security-wise.

If anything, then we might add an explicit set-authscheme, although I
suspect for your use case it would be more useful to somehow enforce
view-only access for the students.

cheers,
  Gerd