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

Tom Herbert <tom@herbertland.com> Tue, 12 November 2019 16:19 UTC

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From: Tom Herbert <tom@herbertland.com>
Date: Tue, 12 Nov 2019 08:18:44 -0800
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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 Mon, Nov 11, 2019 at 11:07 PM Peter Gutmann
<pgut001@cs.auckland.ac.nz>; wrote:
>
> Tom Herbert <tom@herbertland.com>; writes:
>
> >The problems of protocol ossification and middleboxes meddling in E2E
> >protocols has been discussed at length in IETF in various contexts.
>
> I'm aware of RFC 3234, which was written seventeen years ago and focuses on
> middleboxes messing with application-layer data, as well as farcical stuff
> like RFC 3424, of the same vintage, but it's mostly complaining rather than
> actual rigorous analysis, and often seems to be based on opposition to
> middleboxes as an article of faith, notoriously manifested in IPsec's "NAT is
> bad, therefore we will make sure IPsec breaks NAT, because NAT is bad", which
> has caused endless headaches for pretty much anyone who's ever had to work
> with IPsec ever since.
>
> In particular for this case, since the discussion is about header encryption
> and not middleboxes in general, I'm not aware of any rigorous analysis of its
> purported benefits, or even a clear statement of its purported benefits,
> something like "here is a definition of the service that header encryption
> provides, here is a real-world study showing that it provides this and
> demonstrating that it can't be readily defeated".  Contrast this with the two
> dozen plus studies that look at the analysis of encrypted traffic despite the
> encryption, an example being (just one picked at random) "Identifying HTTPS-
> Protected Netflix Videos in Real-Time", Andrew Reed and Michael Kranch,
> Proceedings of the 7th Conference on Data and Application Security and Privacy
> (CODASPY'17), March 2017, p.361.

Peter,

https://www.iab.org/wp-content/IAB-uploads/2014/12/semi2015_huitema.pdf
describes with some detail how encryption of the transport layer is
beneficial to resolve the tussel that results in protocol
ossification.

>From that document: "We know that embedding encryption and
authentication inside the transport protocol provides a powerful API
to applications, and also enables sophisticated handling of path
redundancy and mobility... We know all that because we have tried it
before.", also "The effect of middle-boxes on transport protocols is
obvious."

Tom

>
> So when people complain that the draft doesn't say enough about all the Good
> Things header encryption provides, I would respond that it does, it's cited
> all of the available literature on the benefits of header encryption, and all
> of the studies showing that it's effective, in Appendix B.
>
> The draft is actually quite restrained in this regard, as I mentioned in my
> previous message the two notable examples of header encryption/protection
> deployed at scale into the real world, IPsec and SSH, have both been a
> disaster (for functionality, IPsec, and security, SSH), but it very politely
> omits mention of this.
>
> Peter.