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

Colm MacCárthaigh <colm@allcosts.net> Thu, 04 May 2017 01:39 UTC

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From: Colm MacCárthaigh <colm@allcosts.net>
Date: Wed, 03 May 2017 18:39:13 -0700
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Subject: Re: [TLS] Security review of TLS1.3 0-RTT
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On Wed, May 3, 2017 at 6:19 PM, Viktor Dukhovni <ietf-dane@dukhovni.org>
wrote:

> One obvious use case for 0-RTT is DNS queries.  The query protocol is
> idempotent, and latency matters.  So for DNS over TLS, 0-RTT would be
> a good fit.   TLS session caches are not attractive on the DNS server
> given the enormous query volumes, but STEKs would be a good fit.
>

As it happens, DNS queries are not idempotent.  Queries have side-effects,
for example Bind9 will rotate an RRset by one increment on each query.
Many providers charge by the DNS query. Many providers throttle DNS queries
(and TLS is intended as a mechanism to help prevent the ordinary spoof
ability of DNS queries).


-- 
Colm

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