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Re: [TLS] Security review of TLS1.3 0-RTT

Colm MacCárthaigh <colm@allcosts.net> Thu, 04 May 2017 18:32 UTC

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From: Colm MacCárthaigh <colm@allcosts.net>
Date: Thu, 04 May 2017 11:32:48 -0700
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To: Andrei Popov <Andrei.Popov@microsoft.com>
Cc: Ilari Liusvaara <ilariliusvaara@welho.com>, "tls@ietf.org" <tls@ietf.org>
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Subject: Re: [TLS] Security review of TLS1.3 0-RTT
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On Thu, May 4, 2017 at 11:29 AM, Andrei Popov <Andrei.Popov@microsoft.com>
wrote:

>
>    - Providers already work hard to maximize user affinity to a data
>    center for other operational reasons; re-routing is relatively rare and
>    quickly repaired by issuing a new ticket.
>
> Understood, but isn’t an attacker going to be able to re-route at will?
>

Yes, but I don't see the significance.  If the attacker reroutes the user,
or replays a ticket, to a different data center - the ticket won't work,
it'll degrade gracefully to a regular connection.  Of course the attacker
succeeded in slowing the user down, but that's possible anyway.

Maybe you're thinking of a strike register that shares a global namespace?
That would be an implementation error; tickets should be scoped to the
location they are issued from, and checked against its strike register (or
not used at all).

-- 
Colm

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