Re: [rtcweb] Mandating encryption of RTP header extensions for MID and RID SDES items

"Cullen Jennings (fluffy)" <fluffy@cisco.com> Thu, 13 October 2016 18:12 UTC

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From: "Cullen Jennings (fluffy)" <fluffy@cisco.com>
To: Magnus Westerlund <magnus.westerlund@ericsson.com>
Thread-Topic: [rtcweb] Mandating encryption of RTP header extensions for MID and RID SDES items
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Date: Thu, 13 Oct 2016 18:12:28 +0000
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Cc: RTCWeb IETF <rtcweb@ietf.org>
Subject: Re: [rtcweb] Mandating encryption of RTP header extensions for MID and RID SDES items
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I think this is huge complexity that is not currently supported and not needed. How about we generate the RID such that the RID for the n'th m line is n. Or generate it as a random number. Do you see any problem with this?

I think this removes all the fingerprinting issues. I'm fine with advice that say how to generate the RID in a way that is privacy sensitive but I'm not a fan of making RID require support for RTP header encryption. 



> On Oct 6, 2016, at 7:55 AM, Magnus Westerlund <magnus.westerlund@ericsson.com> wrote:
> 
> WG,
> 
> After discussion in AVTEXT and MMUSIC regarding the inclusion of MID and RID as SDES items that this do exposes labels that previously only have existed in the signalling plane in the media plane. And especially in the RTP header extensions, where even if the media payload is encrypted the header extension is not encrypted.
> 
> The risk with this is primarily a privacy and fingerprinting risk. And the proposed mitgation is encryption of the RTP header extensions in both the bundle and avtext-rid documents.
> 
> This leads to the conclusion that for RTCWeb, we must consider to act on these recommendations and decide on which implementation and usage requirement the protection of these field should have.
> 
> My proposal is that implementation and use of RFC6904 encryption of the RTP header extensions are REQUIRED. For RTCP it is actually unclear if there is mandatory to use encrypted SRTCP. I think it should be required and that can be clarified in Section 5.5 of draft-ietf-rtcweb-security-arch.
> 
> 
> Opinions?
> 
> 
> Cheers
> 
> Magnus Westerlund
> 
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