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

[Magnus Westerlund <[e-mail]>]

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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