I can see that you are looking for some more information on how strp and zrtp work. I have found quite a bit of information on this topic at the following url:

http://www.google.com/search?q=srtp+zrtp

Mike

On Apr 7, 2010, at 2:00 AM, SERGE TUMBA wrote:

hello Jason,
 
Thank you for your prompt responses and you have been very helpfull. I also tried SRTP on Asterisk and I got virus when downloading libraries ... and I also found ZRTP is better. However, can you be specific about SRTP interoperability with end-points that support it? it looks like this is a benefit of SRTP over ZRTP? While ZRTP is based on SRTP right?
 
Thank you!
 
Serge.
 

> Date: Wed, 7 Apr 2010 15:06:41 +1000
> From: jason@jasonjgw.net
> To: freeswitch-users@lists.freeswitch.org
> Subject: Re: [Freeswitch-users] SRTP on FreeSWITCH
> 
> SERGE TUMBA <serget68@msn.com> wrote:
> > 
> > I know that FreeSWITCH supports ZRTP but I would like to know if someone already tried to deploy SRTP on FreeSWITCH? If so, can I have the HOWTO describing this setup if any have been done?
> 
> I tried it, but it exposed bugs in OpenSSL. Soon thereafter, ZRTP became
> available so I switched to that.
> 
> If you want SRTP, you have to turn on TLS, make sure that both ends are using
> it, and enable SRTP in the SIP profile, if I remember correctly. ZRTP is
> better in my opinion; the only reason why you would want to use SRTP is for
> interoperability with end-points that support it, but not ZRTP - unless you
> have a public-key infrastructure in place that you want to use for some
> reason.
> 
>