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Re: [Ntp] Antw: [EXT] Re: Post NTS, Is shared key authentication interesting?

"Salz, Rich" <rsalz@akamai.com> Wed, 27 May 2020 13:41 UTC

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From: "Salz, Rich" <rsalz@akamai.com>
To: Harlan Stenn <stenn@nwtime.org>, "ntp@ietf.org" <ntp@ietf.org>
Thread-Topic: [Ntp] Antw: [EXT] Re: Post NTS, Is shared key authentication interesting?
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Date: Wed, 27 May 2020 13:41:46 +0000
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References: <68248D4C020000916A6A8CFC@gwsmtp.uni-regensburg.de> <54A83DA70200003B43047E14@gwsmtp.uni-regensburg.de> <5ECE33E0020000A10003934B@gwsmtp.uni-regensburg.de> <20200527095536.GR2915@roeckx.be> <FAE302D1-126A-4393-9208-8EC1D9F6A7BD@akamai.com> <3c0b465c-69d7-2802-7963-a26d48e9931e@nwtime.org>
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Subject: Re: [Ntp] Antw: [EXT] Re: Post NTS, Is shared key authentication interesting?
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    > This is known as an oracle, and from this kind of thing, it is possible to do pretty fine-grain timings and figure out keys.  This is often surprising to folks, but look up "Lucky Thirteen" as an example. 

>    So where is this attacker?

On the network.  Anywhere on the Internet.

Maybe for this case it doesn't matter (I am not convinced), but it is worth reinforcing as a design principle.

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