[asterisk-security] ZRTP support in Asterisk

[Alejandro Cabrera Obed]

Dear all, I have the following SIP scenario in my company:

SIP server: Asterisk 1.4.13 with Zaptel 1.4.5.1, without any patch
Windows XP SIP clients: SJPhone 1.65.377a (last version) with Zfone
(last version 10-june-2008)
Debian Etch SIP clients: Twinkle 0.9-6 with libzrtpcpp-0.9-2 (stable
packages)

We can encrypt Twinkle-to-Twinkle voip calls, because we can see the SAS
string and after that we can accept it and encrypt.

But we can't encrypt Windows-to-Twinkle or viceversa voip calls, the
ZRTP support doesn't work.

I heart there is a ZRTP patch for Asterisk, so I have this question:

Is it necessary to apply any ZRTP patch to the Asterisk tarball ???
Because I could encrypt Twinkle-to-Twinkle calls with ZRTP, so I'm not
sure what to do.

Please tell me your experience with Asterisk and ZRTP.

Special thanks,

Alejandro