Re: [Ntp] Follow-up to yesterday's mic comment about PTP security

Watson Ladd <watsonbladd@gmail.com> Wed, 24 July 2019 16:11 UTC

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From: Watson Ladd <watsonbladd@gmail.com>
Date: Wed, 24 Jul 2019 09:10:55 -0700
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To: Daniel Franke <dfoxfranke@gmail.com>
Cc: NTP WG <ntp@ietf.org>
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Subject: Re: [Ntp] Follow-up to yesterday's mic comment about PTP security
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On Tue, Jul 23, 2019, 9:20 AM Daniel Franke <dfoxfranke@gmail.com>; wrote:

> My comments yesterday about PTP security shifted context a few times
> so it may have been hard to follow what I was claiming. My assertions
> were:
>
> 1. If you need 50ms precision, pick some good public NTP servers and use
> NTS.
>
> 2. If you need 100µs precision, colocate a time source in the same
> datacenter as the client systems. Use NTP and NTS; you don't need PTP
> for this.
>
> 3. If you need 1µs precision, use PTP and physically secure the link
> between the time source and the clients so that cryptographic
> authentication is unnecessary.
>
> 4. If you need 1µs precision over an adversarial network, good luck!
> This is simply not achievable and no amount of cryptographic pixie
> dust is ever going to save you.
>

Even if I use the wireless cards PLL, and align times with symbol
boundaries? That's probably beyond scope but NASA does it.


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