[VOIPSEC] mikey for group calls

[Torsten]

Hey,

i have a question on secure group calls using MIKEY. It is written in
the RFC, that it is not possible to use Diffie Hellman for group calls,
only public-key encryption and pre-shared keys. In section 8.2 of the
RFC, you can see a figure showing a small-size interactive group; I
think this is the best way to establish a 3-way conference. Each client
sets up the security for its outgoing streams. Why it is not possible to
use DH in this scenario?
Are there other solutions for setting up a secure 3-way conference using
MIKEY?


Torsten