Re: [rtcweb] security-arch: RTP and RTCP Key Management (mux and non-mux)

Bernard Aboba <bernard.aboba@gmail.com> Tue, 22 July 2014 17:18 UTC

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From: Bernard Aboba <bernard.aboba@gmail.com>
Date: Tue, 22 Jul 2014 13:18:35 -0400
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To: Martin Thomson <martin.thomson@gmail.com>
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Subject: Re: [rtcweb] security-arch: RTP and RTCP Key Management (mux and non-mux)
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Martin said:

"Yeah, keying multiple SRTP sessions from a single DTLS session could
(would) lead to key reuse if the different sessions use the same SSRC
values.  That's why 5764 says what it says."

[BA] Yes - but the question was about deriving SRTCP and SRTP keys from a
single DTLS session when RTP and RTCP are not multiplexed.   That wouldn't
result in key reuse.


On Tue, Jul 22, 2014 at 11:59 AM, Martin Thomson <martin.thomson@gmail.com>
wrote:

> On 21 July 2014 20:33, Bernard Aboba <bernard.aboba@gmail.com> wrote:
> > [BA] My question is whether WebRTC permits DTLS-SRTP sessions to share a
> > single DTLS session or not.
>
> Yeah, keying multiple SRTP sessions from a single DTLS session could
> (would) lead to key reuse if the different sessions use the same SSRC
> values.  That's why 5764 says what it says.
>
> Writing this down makes sense, though we need only lean on what 5764 says.
>