Encrypted calls - Cryptophone.de protocol

[sh]

Hi Mikko!

I'm currently creating the application you've described. I'm (will be)
using HCD (GSM data connections) to deliver encrypted voice data.

I've tried using pulseaudio on the Neo 1973 (haven't got a freerunner)
It turns out it is way too slow. At the moment, I'm using portaudio
because that one is way better documented than alsa (at least for the
full-duplex part).

At the current stage, I can compress the audio data coming from the
microphone with speex, decompress it and the play it back to the
speakers/headphone.

In the weeks to come I'll add AES for encryption and see how to pipe
that data stream through the modem. When it is at the stage where I can
create a stable connection with pre-shared keys, I'll release the first
version to the public.

It will be licensed under the GPL, but at the moment I really need
to make it stable, optimize it and run a few tests before I'll release
it ;-)

Future plans include compatibility with the cryptophone protocol and the
option to use a PKI for session key exchange.

Sincerely
- Soeren