asterisk users - Mar 2007 - SRTP vs ZRTP in Asterisk

Hi All,

I've been reading about Phil Zimmermann's ZRTP encryption scheme for
SIP clients. This seems attactive but I don't use soft phones. I'm
guessing that we'd need ZRTP support in Asterisk in 
order to use it to secure calls from hard phones. 

There seem to be issues with SRTP key exhange between various devices.
So much so that the IETF is working on a standardization project. ZRTP,
which is one of the proposals before the 
IETF,  overcomes this. Since Zimmermann has open sourced the protocol I
would hope that it could be implemented in Asterisk without too much
trouble. 

Does the current work on SRTP extend into ZRTP? 

Michael

My understanding based on the notes from the IETF meeting last week is that
the SRTP Key Exchange group met and is considering two options.  They are
exploring DTLS and ZRTP.  (There was a third option on the table which they
are no longer exploring)  The biggest issue with ZRTP seems to be non-technical
(ie Intellectual Property).

  Shlomo

--- Asterisk Users Mailing List
- Non-Commercial Discussion <asterisk-users@lists.digium.com wrote:
Hi All,
> 
> I've been reading about Phil Zimmermann's ZRTP encryption scheme
for
> SIP clients. This seems attactive but I don't use soft phones. I'm
> guessing
that we'd need ZRTP support in Asterisk in 
> order to use it to secure calls
from hard phones. 
> 
> There seem to be issues with SRTP key exhange between
various devices.
> So much so that the IETF is working on a standardization
project. ZRTP,
> which is one of the proposals before the 
> IETF,  overcomes
this. Since Zimmermann has open sourced the protocol I
> would hope that
it could be implemented in Asterisk without too much
> trouble. 
> 
> Does
the current work on SRTP extend into ZRTP? 
> 
> Michael
> 
> 
> 
>
> 
> 
> 
> 
> 
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On 26 Mar 2007, at 22:32, Michael Graves wrote:
> Hi All,
>
> I've been reading about Phil Zimmermann's ZRTP encryption scheme
for
> SIP clients. This seems attactive but I don't use soft phones. I'm
> guessing that we'd need ZRTP support in Asterisk in
> order to use it to secure calls from hard phones.
>
> There seem to be issues with SRTP key exhange between various devices.
> So much so that the IETF is working on a standardization project.  
> ZRTP,
> which is one of the proposals before the
> IETF,  overcomes this. Since Zimmermann has open sourced the  
> protocol I
> would hope that it could be implemented in Asterisk without too much
> trouble.
>
> Does the current work on SRTP extend into ZRTP?
At Etel I heard Phil Zimmermann say that he had a working implementation
of ZRTP for asterisk in the lab.

What was less clear was how/when this might be released.

Tim Panton

www.mexuar.net
www.westhawk.co.uk/