Encrypted calls - Cryptophone.de protocol

[Thomas Gstädtner]

schmitz_dirk at email.de schrieb:
> Hello Sören,
>
> I hope this email will be delivered to you and also the community?!
> I only follow the mailinlists, but it's the first time to ask and send a email.
> Sorry if I made a technical mistake.
> So, my question is: What do you mean with "I'm (will be)
> using HCD (GSM data connections) to deliver encrypted voice data."
> Do you mean GPRS, so i need a data plan? Sorry for this maybe simple or stupid question.
>
> Many Thanks in advance!
>
> best regards
>
> Dirk
>
>
> -----Ursprüngliche Nachricht-----
> Von: "sh"<soeren at heisrath.org>
> Gesendet: 23.08.08 00:36:31
> An: Mikko Rauhala<mjrauhal at cc.helsinki.fi>
> CC: devel at lists.openmoko.org
> Betreff: Re: Encrypted calls - Cryptophone.de protocol
>
> 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
>
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>
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>    
No, he's talking about "HCD" (I think he means HSCSD), means the 
connection is circuit switched, not packet switched as GPRS is.
So no, this has nothing to do with a common data plan.

But well, HSCSD is not that much supported (and doesnt guarantee the 
high bitrate - only 1 timeslot is guaranteed I think, not the 8 you 
could get max.) , but I think CSD could be enough.