Encrypting voice comunications..

[Harald Welte]

On Fri, Feb 02, 2007 at 07:13:12PM +0200, Mikko J Rauhala wrote:
> On pe, 2007-02-02 at 09:06 -0800, Tim Newsom wrote:
> > If we have access to the mic and speakers while a call is in process, 
> > and we have the ability to record conversations etc...  Where does the 
> > processor sit in that chain?  Can we consume the voice, encrypt it and 
> > feed an encrypted datastream back out to the gsm module which would 
> > transmit it and another neo1973 user could receive the stream, process 
> > through decryption and play out?
> 
> No. The GSM processor does its own audio de- and encoding, and its
> connection to the audio i/o is analog, as reported by LaF0rge on irc a
> while back (any misunderstanding is probably mine if present, though).
> We can get at the audio via the a/d converters, but not do anything
> really fancy directly.
> 
> Thus, I refer you to my last mail; make a GSM data call (phone-to-phone
> if possible, 

Yes, that's also how commercial products like GSMK's cryptophone work
(http://www.cryptophone.com/)

-- 
- Harald Welte <laforge at openmoko.org>          	        http://openmoko.org/
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