Encrypt Your Mobile VoIP Calls

Whisper Systems, announced the availability of it public beta Mobile Security Suite, with two applications for Encrypting SMS and VoIP calls on Android devices.

The VoIP application uses a new method of establishing a call using SMS as a signaling protocol instead of the initial SIP signaling, to overcome the SIP constant connection requirements.

The encryption is done using the well-known ZRTP protocol to setup SRTP stream between the 2 devices.

Here is how it works:

• The caller uses the RedPhone software normally to call any RedPhone number, the software will contact the RedPhone infrastructure, which will send an encrypted SMS to the destination RedPhone device.
• The received SMS will activate the RedPhone VoIP client on the destination, and the call will then start the normal sequence.

The 2nd application is TextSecure, which uses OTR encryption protocol with ECC.

Pretty neat idea, but it is only available in US for now, and only on Android devices.