running voice data/encryption on compal?

Fabio Pietrosanti (naif) lists at infosecurity.ch
Sat Jan 15 20:56:48 UTC 2011


On 14/01/11 23.57, Steve Markgraf wrote:
> One commit says more than thousand words:
>
> http://bb.osmocom.org/trac/changeset/999254a3a6641ea112b48c1eca65599fb9989185/src
>
>
> Sylvain also has a uncommitted code that allows to fill the uplink TCH
> data, and Andreas has code for connecting this to the LCR.
Woah!

I should probably get a couple of phones to play!

It would be interesting to try to get each audio samples incoming and
outgoing and XOR it, to see if other party receive it "as-is", that
would means that no-transcoding happened.

Maybe there are an area of conditions where transcoding doesn't happen,
like within the same operator or within national gsm operators
interconnections.

If that could be confirmed, it would be possible to have a low latency
full-duplex communication data path at 13.3kbit/s (GSM codec) or
12.2kbit (GSM EFR/AMR codec) to be managed such like a serial connection.

On top of a protocol alike HDLC could provide a serial connection over a
GSM voice raw transport

Someone willing to make a try?

-naif




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