Re: [Atlas] Status Update

Hi Mirja,

You are correct that this work does not require a lot of standardization. I actually consider this a feature rather than a bug since after all the idea of this exercise is re-use. The alternative is to essentially re-design the DTLS/TLS protocol, which is being proposed by others.

Thanks for the pointer to your document. I haven't seen it before. Let me read through it and provide you feedback.

Ciao
Hannes

-----Original Message-----
From: Atlas [mailto:atlas-bounces@ietf.org] On Behalf Of Mirja Kühlewind
Sent: 19 June 2018 18:53
To: atlas@ietf.org; Tommy Pauly; Chris Wood
Subject: Re: [Atlas] Status Update

Hi all,

writing as an individual contributor, not an IESG member.

I just briefly looked at draft-friel-tls-atls-00 and when I saw Figure 6, I have to say that I do wonder a bit what additional standardization is needed here. The new parts are the key export and the App Data Crypto box. However, the key export is mainly an interface question and to my understanding there are by now already libraries that provide the needed interface for quic. And the actual app data crypto should be rather straight forward and probably does not need that much standardization...?

In the context of taps, however, we've been thinking about how to even more generalize this approach (in figure 6). The two points I think could be generalized here even more are

1) The TLS handshake should be completely separated from the crypto and could be run directly by the TLS stack without "tunneling" it through the application. Effectively, in theory the handshake would not even need to use the same transport connection or transport protocol than the application (also it probably could).

This also something we discuss/propose in this draft as input for taps:
https://tools.ietf.org/html/draft-kuehlewind-taps-crypto-sep-02

2) The TLS handshake could negotiate within one handhshake multiple key shares that can be used on different layers for different protocols and algorithms. I guess that is more a question/request for the TLS working group but goes into the same direction of separating handshake/control and the actual crypto more.

Mirja

On 19.06.2018 15:23, Abhijan Bhattacharyya wrote:
> Hello Hannes,
> Thanks for the update. The revise charter looks good. So what can we
> expect in Montral? Do we expect another attempt towards a BoF?
> I have a view against the particular observation of low activities in
> the mailing list. I think what ATLAS is trying to do is to collect and
> coordinate between different relevant stray proposals (which may have
> already been worked out) under a single consolidated standardization
> effort. So, the activities are waiting at a threshold of a coordinated
> future progress. But, more activities in this list is definitely a
> proposition to establish the point of interest for the IETF community.
>
> With Best Regards
> Abhijan Bhattacharyya
> Associate Consultant
> Scientist, TCS Research
> Tata Consultancy Services
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> -----"Atlas" <atlas-bounces@ietf.org <mailto:atlas-bounces@ietf.org>>
> wrote: -----
> To: "atlas@ietf..org <mailto:atlas@ietf.org>" <atlas@ietf.org
> <mailto:atlas@ietf.org>>
> From: Hannes Tschofenig
> Sent by: "Atlas"
> Date: 06/08/2018 05:14PM
> Subject: [Atlas] Status Update
>
> Hi all,
>
> Owen and I submitted another BoF proposal to the IESG based on the
> feedback from the last IETF meeting.
>
> Here is the most recent charter text we came up with:
>
> ---
>
> There are multiple scenarios where clients and servers need to
> negotiate shared encryption keys and establish secure, authenticated,
> integrity-protected, end-to-end encrypted sessions at the application
> layer over untrusted transport. There are a proliferation of transport
> protocols and mechanisms in use today across web and IoT use cases
> including, but not limited to, TCP, UDP, IP, Bluetooth and Zigbee.
> Additionally, network topologies often include middleboxes and proxies
> that terminate transport layer connections from clients and
> re-originate new transport layer connections towards the servers. From
> the clients and servers perspective, these transport layer proxy
> functions are untrusted and application data must be protected and
> encrypted, and not exposed to these proxies. There are multiple
> potential mechanisms that could be considered for negotiation of
> encryption keys, and establishment of end-to-end encrypted sessions at
> the application layer between clients and servers, and this working
> group proposes use of existing (D)TLS protocols and stacks.
>
> This working group proposes reuse of (D)TLS at the application layer
> as a simple and straightforward means of achieving the security and
> implementation goals. The primary purpose of the working group is to
> develop specifications defining how (D)TLS can be leveraged at the
> application layer (i.e. Application Layer TLS or ATLS) to establish
> end-to-end encrypted sessions over a multitude of different transports.
>
> Additionally, during development of ATLS specifications, the working
> group will consider and address concerns such as:
>
> o complex, multi-hop and lossy transport topologies
>
> o (D)TLS record fragmentation at the transport layer
>
> o middlebox operators whose goals include interception of application
> layer data
>
> The working group will engage with other relevant working groups
> across the Applications and Real-Time Area (art), Security Area (sec)
> and Transport Area (tsv), and one of the goals of this working group
> is to explicitly identity all related working groups that must be
> consulted during ATLS specifications development.
>
> ---
>
> There do not seem to be minutes available from the IESG/IAB BoF
> discussions and how they reached their conclusions. So, we can only
> report what has been told to us by proxy.
>
> In any case, the IESG rejected the BoF proposal.
>
> The impression from the IESG was that the Bar BOF in London produced
> mixed feelings and that there was no activity on the list afterwards.
>
> Another comment was that the required standardization effort is too
> small to justify the setup of an entire working group.
>
> At first, this sounds a bit negative. On the other hand, we have two
> implementations right now. While they need to be polished I believe
> this is something we could go forward with.
>
> Ciao
> Hannes
>
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