We just released a technical howto on how to build up Secured mobile to landline VoIP infrastructure with:
- Asterisk 1.8 (just released, support SIP/TLS + SDES key exchange for SRTP)
- PrivateGSM Enterprise (Nokia / iPhone / Blackberry)
- SNOM 300 Desktop phone
In next weeks others howto like this one will come out by using other server platforms such as FreeSWITCH, all in the spirit of transparency and leverage of opensource security technologies.