Re: [dispatch] Updated PERC Charter proposal

[Göran Eriksson AP <[e-mail]>]

Hi,

I have some minor comments concerning the meaning of ³SIP² and ³WebRTC²
endpoints.

Sorry for the late response and for top-posting but it became a bit messy
to add inline:

1. The link to 
https://datatracker.ietf.org/doc/draft-ietf-rtcweb-overview/ did not work?
2. The text uses ³SIP² and ³WebRTC² to describe the different kind of
end-points that are in scope.
   W3C WebRTC WG recognises the fact that the WebRTC end points can be
browser end points 
   (browser + web (client portion of) web app) or native WebRTC (or rather
rtcweb) clients and both are in scope for the W3C WG.
   The browser endpoint trust model is different from that of native
clients and it is also evolving.
   I think that clarity in how different endpoints trust model and
security framework look like and different is beneficial for several of
the deliverables, notably 2,3 and 5.

3. The charter says it will ³notify² W3C WebRTC about this activity; what
do the WG expect to get back and why not Œcoordinate¹? And are there other
W3C WG¹s that are relevant?


Again, sorry for not being able to give this feedback previously. If all
of the above is clear to anyone except me, then I do apologise for having
missed that. 
In any case, I personally see these comments as minor and about
clarifications, neither which should prevent the charter from being
submitted to IESG.

Best Regards
Göran

-----Original Message-----
From: Mary Barnes <[e-mail]>
Date: Friday 22 May 2015 17:52
To: Dispatch <[e-mail]>
Cc: Barry Leiba <[e-mail]>, Ben Campbell <[e-mail]>
Subject: [dispatch] Updated PERC Charter proposal

>Hi all,
>
>
>Below, please find an updated charter for PERC.  Magnus has updated the
>charter to incorporate feedback from the DISPATCH WG mailing list
>discussions and we've made a round of editorial changes.  It should be
>ready for Ben to submit to the IESG for
> consideration as a new WG.  So, please review and provide any final
>comments no later than 18:00 GMT on Monday, May 25th (and yeah, I know
>it's a US holiday but folks in the US have the rest of today to review
>and there really should be no surprises;)
>
>
>Regards,
>Mary
>DISPATCH WG co-chair
>
>
>
>
>=========================================================================
>
>
>
>
>
>Name: Privacy Enhanced RTP Conferencing (PERC)
>Area: ART
>Chairs: TBD
>Mailing List: <using
>[e-mail]
> for now> 
>
>Motivation for new WG
>
>RTP-based real-time multi-party interactive media
> conferencing is in widespread use today. Many of the deployments use one
>or more centrally located media distribution devices that perform
>selective forwarding of mixed-media streams received from the
>participating endpoints. The media transport protocol commonly
> used is RTP (RFC3550). There are various signaling systems used to
>establish these multi-party conferences.
>
>
>These
> conferences require security to ensure that the RTP media and related
>metadata of the conference is kept private and only available to the set
>of invited participants and other devices trusted by those participants
>with their media.  At the same time, multi-party
> media conferences need source authentication and integrity checks to
>protect against modifications, insertions, and replay attacks.  Media
>distribution devices supporting these conferences may also perform RTP
>header changes, and they often consume and create
> RTCP messages for efficient media handling.
>
>
>To date, deployment models for these multi-party
> media distribution devices do not enable the devices to perform their
>functions without having keys to decrypt the participants¹ media,
>primarily using Secure RTP (RFC3711) to provide session security.
>
>
>This trust model has limitations and prevents or
> hampers deployment of secure RTP conferencing in a multitude of cases,
>including outsourcing, legal requirements on confidentiality, and
>utilization of virtualized servers. Thus, a new architectural model and
>related specifications are needed, with a focused
> effort from the RTP and Security communities.
>
>WG Objectives
>
>This WG will work on a solution that enables centralized
> SRTP-based conferencing, where the central device distributing the media
>is not required to be trusted with the keys to decrypt the participants¹
>media. The media must be kept confidential and authenticated between an
>originating endpoint and the explicitly
> allowed receiving endpoints or other devices.  Further, it is desired
>that a solution still provides replay protection, so that the media
>distribution devices can¹t replay previous parts of the media.
>
>The solution must also provide security for each
> hop between endpoints and multi-party media distribution devices and
>between multi-party media distribution devices. The RTCP messages and RTP
>header extensions required for the media distribution device to perform
>the selective media forwarding may require
> both source authentication and integrity as well as confidentiality. The
>solution may also consider providing end-to-end security for a subset of
>the RTCP messages or RTP header extensions.
>
>The solution should be implementable by both SIP
> (RFC3261) and WebRTC (draft-ietf-rtcweb-overview
><https://datatracker.ietf.org/doc/draft-ietf-rtcweb-overview/>)
> endpoints. How telepresence endpoints using the protocols defined in the
>CLUE working group could utilize the defined security solution needs to
>be considered. However, it is acknowledged that limitations may exist,
>resulting in restricted functionality or
> need for additional adaptations of the CLUE protocols.
>
>This working group will perform the following work:
>
>1.
>    Define a general architecture and RTP topology(s) that enables
>end-to-end media security for multi-party RTP
> conferencing.
>2.
>    Define the trust model and describe the resulting security properties.
>3.  Document models considered for integrating the solution with WebRTC,
>SIP and CLUE establishment of conferencing sessions.
>4.
>    Specify any necessary extensions to SRTP.
>5.
>   Define needed Key Management Functions that distribute the keys. The
>system needs to be able to bind the media
> to the sender of the media¹s identity and/or the identity of the
>conference. 
>
>Collaboration
>
>If there is identification of missing protocols
> or functionalities, such work can be requested to be done in another
>working group with a suitable charter or by requests for chartering it in
>this WG or another WG. Potential items that might require work in other
>WGs are DTLS extensions (TLS WG) and RTP
> header extensions (AVTEXT WG). This work requires strong collaboration
>with the security area. We will notify AVTCore, CLUE, MMUSIC, RTCWEB,
>SIPREC, W3C WebRTC, and other related groups about this work.
>
>
>Non-Goals
>
>The PERC working group is not chartered to extend
> any signaling system used to establish the RTP-based conferences. It
>will, however, need to consider in its architecture how the solution may
>integrate with these systems, and document such consideration for WebRTC,
>SIP, and CLUE. The specification of how
> a particular system integrates the security solution will happen outside
>of this working group, in suitable venues.
>
>
>The WG will not consider non-real-time usage, multicast-based
> media distribution, or Security descriptions-based keying (RFC4568).
>
>Goals and Milestones
> 
>TBD  Submit architecture or framework specification
> to IESG (Standards Track)
>
>TBD Submit documentation of how to integrate solution
> in SIP, WebRTC and CLUE to IESG (Informational)
>
>TBD  Submit SRTP protocol extension specification
> to IESG (Standards Track)
>
>TBD  Submit Key-management protocol specification
> to IESG (Standards Track)
>
>
>Input to the WG
>
>Proposals already existing relating to this charter
> proposal:
>
>https://datatracker.ietf.org/doc/draft-jones-avtcore-private-media-reqts/
> 
><https://datatracker.ietf.org/doc/draft-jones-avtcore-private-media-reqts/
>>https://datatracker.ietf.org/doc/draft-jones-avtcore-private-media-framew
>>ork/
> 
><https://datatracker.ietf.org/doc/draft-jones-avtcore-private-media-framew
>ork/>https://datatracker.ietf.org/doc/draft-cheng-avtcore-srtp-cloud/
>
> <https://datatracker.ietf.org/doc/draft-cheng-avtcore-srtp-cloud/>
>
>
>