Re: [Ntp] The NTP WG has placed draft-schiff-ntp-chronos in state "Call For Adoption By WG Issued"

Hal Murray <> Tue, 10 September 2019 10:10 UTC

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From: Hal Murray <>
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Date: Tue, 10 Sep 2019 03:10:17 -0700
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Subject: Re: [Ntp] The NTP WG has placed draft-schiff-ntp-chronos in state "Call For Adoption By WG Issued"
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X-List-Received-Date: Tue, 10 Sep 2019 10:10:25 -0000 said:
> *Threat model: *Chronos considers a powerful form of man-in-the-middle (MitM)
> Byzantine attacker, capable of determining precisely the values of the time
> samples gathered by the Chronos client from a subset of the NTP servers in
> its server pool (up to one-third of the pool). 

I consider that "up to one-third" to be a serious problem.  It doesn't cover 
the case where the bad guy has taken over your ISP (or is your ISP) and thus 
controls all the traffic to the servers you try to use.  I think that's going 
to be a common case.

[Disclaimer: I work on NTS so I'm probably biased.]

Why should we work on this rather than getting NTS deployed?

There is an additional complication.  You are inventing a new method of 
processing the data from packets that get past your filters.

These are my opinions.  I hate spam.