Re: [Ntp] An NTPv5 design sketch

[Miroslav Lichvar <[e-mail]>]

On Sun, Apr 12, 2020 at 12:19:22PM -0400, Daniel Franke wrote:
> This is a sketch of a proposed NTPv5 design (by no means a complete
> spec, but hopefully good enough to make the concepts clear). It's a
> fairly ambitious step forward from previous versions, almost but not
> quite a green field design.  I say "almost" because it retains a
> couple limited backward-compatibility constraints:

Thanks for writing it down.

It's a bit too much for me to digest at once. I think I like the
general direction. I particularly like that it allows phase
adjustments to be separated from the base clock. I'm not sure about
TAI and PTP timestamps.

The main issue for me will probably be the dependency on NTS (and
TLS). I don't think that will work for many clients if NTPv5 is
supposed to replace NTPv4.

If I understand it correctly, the main advantage is that it makes
exploiting of follow-up messages more difficult. But it doesn't
prevent amplification attacks completely, right? An attacker who has
even a brief access to the victim's network, could capture a client
request asking for a follow-up message, or generate its own request,
and use this request for an attack until the server rotates the key
out.

-- 
Miroslav Lichvar