Re: Secure voice software issues

[Derek Atkins <warlord@MIT.EDU>]

> Am I wrong, or is Diffie-Helman only useful when you *don't* have
> a way of verifying who each other are?

No, DH is useful whenever you want to generate a session key between
two entities, and its even more useful because it doesn't require any
prior knowledge.  This means that you don't *need* to verify the
identity of the other person.  

However, without some way of verifying the key of the other party,
there is no easy way to detect a monkey-in-the-middle attack.  As was
put forward, a combination of DH to key exchange and RSA to detect
monkey-in-the-middle will protect you, but you lose your anonymity at
that point.

So, to return to your question, DH is useful even when you have a
method of verification.  So the answer to your question is yes, you
are wrong.

-derek