[Asterisk-video] Secure video with srtp

[Jeffrey C. Ollie]

On Thu, 2006-06-08 at 10:02 +0200, Christian Krützfeldt wrote:
> > -----Original Message-----
> > From: asterisk-video-bounces at lists.digium.com 
> > [mailto:asterisk-video-bounces at lists.digium.com] On Behalf Of 
> > Olle E Johansson
> > Subject: [Asterisk-video] Secure video with srtp
> > 
> > We have a patch for srtp in the bug tracker. This patch 
> > assumes that both streams, audio and video, share the same 
> > encryption properties. Is that always the case? Can we have 
> > secure audio and unsecure video? Different encryption algorithms?
> > Do they always use the same key?
> > 
> > Anyone that has looked into this?
> > 
> > /Olle
> 
> I checked RFC 3711, the interesting part is probably 3.2.3.
> 
> [...]
>
> I'm not 100% sure, but I think it allows different RTP sessions (e.g. audio and video) to share a key, but they don't have to.
> 
> Would different encryption algorithms for audio and video bring any benefits?
> Can we still consider it a secure call if only one is encrypted?

The only scenario that I can think of that leaving the video unencrypted
would be if Asterisk was running on a platform that didn't have very
much CPU power (like a wireless router running OpenWRT) and couldn't
keep up with the flow.

I would think that we would want to be prepared for different encryption
parameters for different streams.

Jeff