Re: [saag] [tsvwg] Comments on draft-ietf-tsvwg-transport-encrypt-08.txt

Eric Rescorla <ekr@rtfm.com> Tue, 12 November 2019 15:55 UTC

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References: <67CE4313-A4C2-4CC7-972E-CB465D47B7FE@ericsson.com> <998B7C3E-54D8-40AC-BF91-901390CF70C5@strayalpha.com> <CAPDSy+5rvaXgEGZ7_V4pRdmBss7Hf1XmaGbiXGZceQu9hjjRTQ@mail.gmail.com> <1573035094775.62307@cs.auckland.ac.nz> <87d3bcef-42e4-1535-db1f-06a8408d38d5@cs.tcd.ie> <1573109463764.56084@cs.auckland.ac.nz>
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From: Eric Rescorla <ekr@rtfm.com>
Date: Tue, 12 Nov 2019 07:54:58 -0800
Message-ID: <CABcZeBMLc0CEhaCOfT=3DE5yq4TaSPh6h+hnJwxYLL93e-FYGw@mail.gmail.com>
To: Peter Gutmann <pgut001@cs.auckland.ac.nz>
Cc: Stephen Farrell <stephen.farrell@cs.tcd.ie>, David Schinazi <dschinazi.ietf@gmail.com>, Joe Touch <touch@strayalpha.com>, "gorry@erg.abdn.ac.uk" <gorry@erg.abdn.ac.uk>, Mirja Kuehlewind <mirja.kuehlewind=40ericsson.com@dmarc.ietf.org>, tsvwg IETF list <tsvwg@ietf.org>, "saag@ietf.org" <saag@ietf.org>
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Subject: Re: [saag] [tsvwg] Comments on draft-ietf-tsvwg-transport-encrypt-08.txt
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On Wed, Nov 6, 2019 at 10:51 PM Peter Gutmann <pgut001@cs.auckland.ac.nz>;
wrote:

> .  So on the one hand we've got real-world experience with two protocols
> that do header encryption/protection which has yielded endless problems
> (IPsec) and security vulns (SSH), and on the other hand we've got what
> seems
> to be a faith-based belief in something that numerous academic papers have
> shown doesn't provide the service it claims to.
>

On the other hand, we also have WebRTC which tunnels SCTP over DTLS (thus
encrypting the SCTP headers) and that seems to work out fine.

As far as "the services it claims to", the primary argument for encrypting
headers in QUIC (and the handshake metadata in TLS 1.3) is to prevent
middleboxes interfering with protocol evolution. We certainly have evidence
of a number of cass where that has happened, though I don't think we yet
have strong evidence that encrypting more of the metadata prevents this
from happening because we mostly just started doing so. OTOH, I'm not aware
of any academic papers showing the contrary.

-Ekr