On 3/4/09 9:31 AM, Dirk Meyer wrote: > Eric Rescorla wrote: >> I must have lost the thread of what you're trying to accomplish here >> somewhere. >> The basic idea behind DTLS-SRTP (and connected identity) is that you trust >> the signalling channel (SIP or the XMPP channel you're using to set up the >> direct connection) to accurately convey the end-party's certificate >> fingerprints so they can be conveyed. There's no real intention to >> verify them independently of that because the niotion is that they are >> verified by RFC 4474 signatures from the proxy responsible for the >> relevant section of namespace.
Naturally we could define such a mechanism for XMPP, especially given the increasingly wide deployment of server certificates on the network. > If you trust your XMPP server and only want to secure the audio stream > against people along the way, it is fine. The e2e streams idea depends > on not trusting the server. The idea was to combine this: how to set up > a secure RTP stream if you do not trust the server? I think it would be helpful to be clear about what kinds of streams we're talking about. By "e2e stream" we mean an end-to-end XML stream (i.e., encryption of the XMPP signalling channel). When you talk about an RTP stream, that is a media session that goes outside the XMPP channel. >> we were trying to achieve because we figured that wasn't the common case. >> So, I'm not sure you need any external validation, especially if you use >> key continuity in the future. > > At least for e2e streams I need something. For secure audio streams I > may not. One idea to make audio streams secure is to start an e2e stream > (secure) and negotiate a rtp stream over that connection. In that case > you can trust the signaling stream. Right. So in that case, you would first set up an end-to-end XML stream (via draft-meyer-xmpp-e2e-encryption) to establish a secure end-to-end XMPP signalling channel. Then once you have that established, you can use the secured XMPP channel to exchange the signalling messages needed to set up an RTP session (or any other kind of session). Peter -- Peter Saint-Andre https://stpeter.im/
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